KR20240176070A - Polycyclic aromatic compound - Google Patents

Abstract

[Assignment] To provide a novel compound useful as a material for organic EL devices.
[Solution] A polycyclic aromatic compound represented by formula (1) and including partial structures represented by formula (Xa-1) and formula (Xb-1);

X ^a is C or Si etc., X ^b is N-AR5 etc., A to E ring, AR1 to AR5 ring are a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, 1 to 2 of AR1 to AR4 rings are bonded to A to C ring through a single bond or a partial structure of formula (Xb-1), or are bonded to A to C ring or A ring to C ring, or share a ring with D ring, E ring or AR5 ring in formula (Xb-1) that shares a ring, and 1 to 2 selected from the group consisting of D ring, E ring and AR5 ring are bonded to A to C ring through a single bond or a partial structure of formula (Xa-1), or are bonded to A to C ring or A ring to C ring, or share a ring with AR1 to AR4 rings in formula (Xa-1) that share a ring.

Description

Polycyclic aromatic compound {POLYCYCLIC　AROMATIC　COMPOUND}

The present invention relates to polycyclic aromatic compounds, organic devices such as organic electroluminescent elements, organic field effect transistors, and organic thin film solar cells using the same, and display devices and lighting devices.

Conventional display devices using electroluminescent light-emitting elements have been studied in various ways because they can be made thinner and power-saving, and organic electroluminescent elements made of organic materials have been actively examined because they can be made lighter and larger. In particular, the development of organic materials having luminescent properties such as blue and green, which are among the three primary colors of light, and the development of organic materials having charge transport capabilities such as holes and electrons (which have the potential to become semiconductors or superconductors) have been actively studied up to now, regardless of whether they are high-molecular compounds or low-molecular compounds.

An organic EL device has a structure composed of a pair of electrodes consisting of an anode and a cathode, and one or more layers containing an organic compound, which are arranged between the pair of electrodes. The layers containing the organic compound include a light-emitting layer, a charge transport/injection layer that transports or injects charges such as holes and electrons, etc., and various organic materials suitable for these layers are being developed.

Currently, three types of luminescent materials are used for the light-emitting layer: fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. For example, among fluorescent materials, materials that are improved azaborine derivatives have been reported (Patent Documents 1 and 2), among phosphorescent materials, noble metal complexes having polydentate ligands have been developed (Patent Document 3), and among thermally activated delayed fluorescence (TADF) materials, carbazonitrile compounds have been developed (Non-patent Document 1).

In devices using any material, a material having a high lowest excited singlet energy or lowest excited triplet energy is used in the adjacent layer or host of the emitting layer to prevent energy leakage from the emitting layer or surrounding layers, which would lead to a decrease in efficiency.

International Publication No. 2015/102118 International Publication No. 2018/212169 Japanese Patent Publication No. 2014-239225

Nature Vol.492 13 December 2012

As described above, various materials used in organic EL devices are being developed, and in order to expand the range of choices for materials for organic EL devices, development of materials composed of compounds different from conventional ones is desired. In addition, patent documents 1 and 2 report polycyclic aromatic compounds containing boron and organic EL devices using the same, and materials for light-emitting layers and peripheral layers that can improve luminous efficiency and device lifespan in order to further improve device characteristics are desired.

The present inventors have conducted extensive studies to solve the above problems, and have succeeded in producing a novel polycyclic aromatic compound, and have found that this compound is effective as a material having higher singlet energy and triplet energy. In addition, for example, by using this polycyclic aromatic compound as a material for a host material or a layer adjacent to a light-emitting layer, and configuring an organic EL device by disposing a light-emitting layer using a compound having a lower triplet energy as a dopant material between a pair of electrodes, they have found that an excellent organic EL device can be obtained, thereby completing the present invention. That is, the present invention provides the following polycyclic aromatic compound, and further, a material for an organic device including the following polycyclic aromatic compound.

＜1＞ A polycyclic aromatic compound represented by formula (1) and comprising at least one partial structure represented by formula (X-a-1) and at least one partial structure represented by formula (X-b-1);

In equation (1),

Ring A, ring B and ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

Among the formulas (X-a-1),

X ^a is C, Si, Ge or Sn, and the AR1 ring, AR2 ring, AR3 ring and AR4 ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR1 ring, AR2 ring, AR3 ring and AR4 ring may each be connected to any one of the other AR1 ring, AR2 ring, AR3 ring and AR4 ring by a single bond or a connecting group,

One or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring,

Is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the A ring, B ring or C ring through a single bond, or

Is bonded to ring A, ring B or ring C, or is bonded to an aryl ring or heteroaryl ring of ring D, ring E or AR5 in formula (X-b-1) that shares one ring with ring A, ring B or ring C, through a single bond,

Sharing a ring with Ring A, Ring B or Ring C, or

It is bonded to ring A, ring B or ring C, or shares a ring with ring D, ring E or AR5 among formula (X-b-1) which shares a ring with ring A, ring B or ring C,

Among the formulas (X-b-1),

D ring and E ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

X ^b is a divalent group represented by the formula (Xb-R5), >O or >S,

Among the formulas (Xb-R5),

The two #s are the bonding positions with the D ring and the E ring, respectively.

The AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR5 ring may be connected to the D ring and/or the E ring by a single bond or a connecting group.

One or two selected from the group consisting of D ring, E ring and AR5 ring,

Is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the A ring, B ring or C ring through a single bond, or

Is bonded to an aryl ring or heteroaryl ring in the AR1 ring, AR2 ring, AR3 ring or AR4 ring in formula (X-a-1) which is bonded to ring A, ring B or ring C, or shares one ring with ring A, ring B or ring C, or is bonded through a single bond,

Sharing a ring with Ring A, Ring B or Ring C, or

It shares a ring with an AR1 ring, AR2 ring, AR3 ring or AR4 ring among formula (X-a-1) which is bound to ring A, ring B or ring C, or shares a ring with ring A, ring B or ring C,

In formula (1), one or more hydrogens may be replaced with deuterium, one or more nitrogens may be replaced with nitrogen-15 ( ¹⁵ N), one or more sulfurs may be replaced with sulfur-33 ( ³³ S), sulfur-34 ( ³⁴ S), or sulfur-36 ( ³⁶ S), one or more oxygens may be replaced with oxygen-17 ( ¹⁷ O) or oxygen-18 ( ¹⁸ O), one or more carbons may be replaced with carbon-13 ( ¹³ C), and one or more borons may be replaced with boron-11 ( ¹¹ B).

＜2＞ A polycyclic aromatic compound described in ＜1＞, wherein at least one ring selected from the group consisting of an AR1 ring, an AR2 ring, an AR3 ring, and an AR4 ring shares a ring with an A ring, a B ring, or a C ring, or a D ring, an E ring, or an AR5 ring in formula (X-b-1) bonded to an A ring, a B ring, or a C ring.

＜3＞ A polycyclic aromatic compound described in ＜1＞, which is represented by formula (1a), formula (1b), or formula (1c), and includes at least one partial structure represented by formula (X-a-2) and at least one partial structure represented by formula (X-b-2);

Among equations (1a), (1b), (1c), (X-a-2), and (X-b-2),

One or two selected from the group consisting of Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring,

is bonded to Z in the a ring, b ring or c ring through a single bond, or

In a partial structure represented by formula (X-b-2) that is bonded to Z among the a ring, b ring or c ring, it is bonded to the d ring, e ring or AR5 ring, or

Sharing a ring with ring A, ring B or ring C, or

is bonded to ring a, ring b or ring c, or shares a ring with ring d, ring e or AR5 among formula (X-b-2) that shares a ring with ring a, ring b or ring c,

One or two selected from the group consisting of d ring, e ring and AR5 ring,

is bonded to Z in the a ring, b ring or c ring through a single bond, or

In the partial structure represented by formula (Xa-2) which is bonded to Z in the a ring, b ring or c ring, or in the Ar ¹ ring, Ar ² ring, Ar ³ ring or Ar ⁴ ring,

Sharing a ring with ring A, ring B or ring C, or

A ring is shared with Ar ¹ ring, Ar ² ring, Ar 3 ring or Ar ⁴ ring among formula (Xa-2) which is bound to ring a, ring b or ring c, or shares a ring with ring ^a, ring b or ring c,

The Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring may each be connected to any one of the other Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring by a single bond or a connecting group,

Y ¹ and Y ² are each independently >NR ^NY , >C(-R ^CY ) ₂ , >O, >Si(-R ^IY ) ₂ , >S or >Se, and R ^NY , R ^CY and R ^IY are each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, and two R ^CY may be combined with each other to form a ring, and two R ^IY may be combined with each other to form a ring,

Z is a carbon atom having a bond with another ring, or -C(-R ^Z )= or -N=, R ^Z is hydrogen or a substituent, provided that two adjacent Z constituting the e ring in formula (Xb-2) may be carbon atoms each bonded to two * of formula (Xb-2-e), and X ^b in formula (Xb-2-e) is a divalent group represented by formula (Xb-R5), >O, >C(-R ^CX ) ₂ , >Si(-R ^IX ) ₂ , >S or >Se, and R ^CX are each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, and two R ^CX may be bonded to each other to form a ring, and R ^IX are each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted Heteroaryl, substituted or unsubstituted alkyl or substituted or unsubstituted cycloalkyl, and two R ^IX may be combined with each other to form a ring,

When X ^b is a divalent group represented by the formula (XB-R5), the AR5 ring is a six-membered ring.

＜4＞ A polycyclic aromatic compound described in ＜3＞ represented by formula (1b) or formula (1c).

＜5＞ A polycyclic aromatic compound described in ＜3＞, wherein X ^a in formula (Xa-2) is C, Ge or Sn, and no two of the Ar ¹ ring, the Ar ² ring, the Ar ³ ring and the Ar ⁴ ring are connected to each other.

＜6＞ A polycyclic aromatic compound described in ＜3＞, wherein X ^a in formula (Xa-2) is Si and at least one of Z is -N=.

＜7＞ A polycyclic aromatic compound as described in ＜3＞, wherein X ^a is Si in formula (Xa-2), and two or more of the Ar ¹ ring, the Ar ² ring, the Ar ³ ring, and the Ar ⁴ ring are connected to each other.

＜8＞ A polycyclic aromatic compound described in ＜3＞, wherein at least one of Z in formula (X-b-2) is -N=.

＜9＞ A polycyclic aromatic compound described in ＜3＞, represented by any one of the following formulas.

＜10＞ A polycyclic aromatic compound described in ＜3＞, represented by any one of the following formulas.

＜11＞ A polycyclic aromatic compound described in ＜3＞, represented by any one of the following formulas.

＜12＞ An organic electroluminescent device having a pair of electrodes consisting of an anode and a cathode and an organic layer disposed between the pair of electrodes, wherein the organic layer contains a polycyclic aromatic compound as described in any one of ＜1＞ to ＜11＞.

＜13＞ An organic electroluminescent device as described in ＜12＞, wherein the organic layer is a light-emitting layer.

＜14＞ An organic electroluminescent device as described in ＜13＞, wherein the polycyclic aromatic compound is an electron-transporting host material, and the light-emitting layer further includes a hole-transporting host material and a dopant material.

＜15＞ An organic electroluminescent device as described in ＜14＞, wherein the light-emitting layer further comprises at least one selected from the group consisting of a thermally activated delayed fluorescent material and a phosphorescent material.

＜16＞ A display device or lighting device having an organic electroluminescent element described in any one of ＜11＞ to ＜15＞.

According to a preferred embodiment of the present invention, by manufacturing an organic EL device using a novel polycyclic aromatic compound as, for example, a host material in a light-emitting layer, a component of a host material, or a component of a layer adjacent to the light-emitting layer, an organic EL device having excellent quantum efficiency or device lifespan can be provided.

Figure 1 is a schematic cross-sectional view showing an organic EL element according to the present embodiment.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments or specific examples, but the present invention is not limited to these embodiments. In addition, in this specification, a numerical range indicated using “~” means a range that includes the numerical values described before and after “~” as lower limits and upper limits. In addition, in the description of the structural formula in this specification, “hydrogen” means “hydrogen atom (H).” Similarly, in cases where an atom such as a “carbon atom (C)” is indicated, “atom” may be omitted (for example, “carbon”).

In this specification, the term “adjacent groups” refers to two groups each bonded to two adjacent atoms (two atoms directly bonded by a covalent bond) in the structural formula.

In this specification, "Me" represents methyl, "Et" represents ethyl, "nBu" represents n-butyl (normal butyl), "tBu" represents t-butyl (tert-butyl), "iBu" represents isobutyl, "secBu" represents sec-butyl, "nPr" represents n-propyl (normal propyl), "iPr" represents isopropyl, "tAm" represents t-amyl, "2EH" represents 2-ethylhexyl, "tOct" represents t-octyl, "Ph" represents phenyl, "Mes" represents mesityl (2,4,6-trimethylphenyl), "Ad" represents 1-adamantyl, "Tf" represents trifluoromethanesulfonyl, "TMS" represents trimethylsilyl, and "D" represents deuterium.

In this specification, an organic electroluminescent device is sometimes referred to as an organic EL device.

In this specification, there are cases where a chemical structure or a substituent is expressed by carbon number. However, in cases where a substituent is substituted in the chemical structure or where a substituent is additionally substituted, the carbon number refers to the carbon number of each chemical structure or substituent, and does not refer to the total carbon number of the chemical structure and the substituent, or the total carbon number of the substituent and the substituent. For example, “a substituent B having carbon number Y substituted by a substituent A having carbon number X” means that “a substituent A having carbon number X” is substituted for “a substituent B having carbon number Y,” and the carbon number Y is not the total carbon number of substituent A and substituent B. In addition, for example, “a substituent B having carbon number Y substituted by a substituent A” means that “a substituent A (without carbon number limitation)” is substituted for “a substituent B having carbon number Y,” and the carbon number Y is not the total carbon number of substituent A and substituent B.

＜Explanation of rings and substituents＞

First, the rings and substituents used in this specification are described in detail below.

As used herein, the “aryl ring” includes, for example, an aryl ring having 6 to 30 carbon atoms, preferably an aryl ring having 6 to 16 carbon atoms, more preferably an aryl ring having 6 to 12 carbon atoms, and particularly preferably an aryl ring having 6 to 10 carbon atoms.

Specific examples of "aryl rings" include a monocyclic benzene ring, a bicyclic bicyclic bicyclic bicyclic bicyclic naphthalene ring, an indene ring, a tricyclic terphenyl ring (m-terphenyl, o-terphenyl, p-terphenyl), a fused tricyclic acenaphthylene ring, fluorene ring, phenalene ring, phenanthrene ring, anthracene ring, a fused tetracyclic triphenylene ring, pyrene ring, naphthacene ring, chrysene ring, and a fused pentacyclic perylene ring, pentacene ring, etc. In addition, the fluorene ring, benzofluorene ring, and indene ring also include structures in which a fluorene ring, benzofluorene ring, or cyclopentane ring is spiro-bonded, respectively. In addition, the fluorene ring, benzofluorene ring, and indene ring include those in which two of the two hydrogens of methylene in the structure are each replaced with an alkyl such as methyl as a first substituent described later, thereby forming a dimethylfluorene ring, a dimethylbenzofluorene ring, a dimethylindene ring, etc.

As used herein, the “heteroaryl ring” includes, for example, a heteroaryl ring having 2 to 30 carbon atoms, preferably a heteroaryl ring having 2 to 25 carbon atoms, more preferably a heteroaryl ring having 2 to 20 carbon atoms, still more preferably a heteroaryl ring having 2 to 15 carbon atoms, and particularly preferably a heteroaryl ring having 2 to 10 carbon atoms. In addition, the “heteroaryl ring” includes, for example, a heterocycle containing 1 to 5 heteroatoms selected from oxygen, sulfur, nitrogen, boron, selenium, phosphorus, and tellurium as ring constituent atoms in addition to carbon.

Specific "heteroaryl rings" include, for example, a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, an oxadiazole ring (such as a furazan ring), a thiadiazole ring, a triazole ring, a tetrazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, an indole ring, an isoindole ring, a 1H-indazole ring, a benzoimidazole ring, a benzoxazole ring, a benzothiazole ring, a 1H-benzotriazole ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinazoline ring, a quinoxaline ring, a phthalazine ring, a naphthyridine ring, a purine ring, a pteridine ring, a carbazole ring, an acridine ring, a phenoxanthine ring, a phenoxazine ring, a phenothiazine ring, Phenazine ring, phenazacillin ring, indolizine ring, furan ring, benzofuran ring, isobenzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, thianthrene ring, indolocarbazole ring, benzoindolocarbazole ring, dibenzoindolocarbazole ring, naphthobenzofuran ring, dioxin ring, dihydroacridine ring, xanthene ring, thioxanthene ring, dibenzodioxin ring, dioxabora naphthoanthracene ring (5,9-dioxa-13b-bora-13bH-naphtho[3,2,1-de]anthracene ring, etc.), benzoselenophene ring, dibenzoselenophene ring, azacarbazole ring, azadibenzothiophene ring, azadibenzofuran ring, azadibenzoselenophene ring, Examples thereof include an azatriphenylene ring, an imidazoimidazole ring, an indoloindole ring, a benzofurocarbazole ring, a benzothienocarbazole ring, an indenocarbazole ring, a selenophenocarbazole ring, a spiro[fluorene-9,9'-xanthene] ring, a spirobi[silafluorene] ring, and the like. In addition, it is preferable that a dihydroacridine ring, a xanthene ring, and a thioxanthene ring have two of the two hydrogens of the methylene in the structure each replaced by an alkyl such as methyl as a first substituent described later, thereby forming a dimethyldihydroacridine ring, a dimethylxanthene ring, a dimethylthioxanthene ring, and the like. In addition, bipyridine ring, phenylpyridine ring, pyridylphenyl ring, which are two-ring systems, and terpyridyl ring, bispyridylphenyl ring, and pyridylbiphenyl ring, which are three-ring systems, can also be included as "heteroaryl rings". In addition, a pyran ring is also included as "heteroaryl ring".

In this specification, a substituent may be substituted with an additional substituent. For example, a specific substituent may be described as "substituted or unsubstituted." This means that the specific substituent is substituted with one or more additional substituents, or is not substituted. In the same sense, there is also the phrase "may be substituted." In this specification, the specific substituent at this time may be referred to as a "first substituent," and the additional substituent may be referred to as a "second substituent."

In this specification, the substituent group Zα is composed of a substituent of the substituent group Z and a substituent represented by the formula (A30) described below.

In this specification, the substituent group Z is

Aryl, which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen;

Heteroaryl which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen,

Diarylamino which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen (two aryls may be connected to each other through a linking group),

Diheteroarylamino which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen (two heteroaryls may be connected to each other through a linking group),

Arylheteroarylamino which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen (aryl and heteroaryl may be bonded to each other through a linking group),

Diarylboryl which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen (two aryls may be connected through a single bond or a linking group),

Alkyl which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, cycloalkyl, cyano and halogen,

Cycloalkyl which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen,

Alkoxy, which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, cycloalkyl, cyano and halogen,

Aryloxy which may be substituted with one or more groups selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen;

It consists of substituted silyl, cyano and halogen.

In each group of the substituent group Z, the second substituent aryl may be further substituted with aryl, heteroaryl, alkyl, cycloalkyl, cyano or halogen, and similarly, the second substituent heteroaryl may be substituted with aryl, heteroaryl, alkyl, cycloalkyl, cyano or halogen.

In the present specification, when referring to a "substituent", the type of the substituent is not particularly limited, but unless otherwise specifically described, any one group selected from the substituent group Z may be used. For example, when a group that is "substituted or unsubstituted" is substituted, the group may be substituted with one or more groups selected from the substituent group Z.

In the present specification, “aryl” is, for example, aryl having 6 to 30 carbon atoms, preferably aryl having 6 to 20 carbon atoms, aryl having 6 to 16 carbon atoms, aryl having 6 to 12 carbon atoms, or aryl having 6 to 10 carbon atoms.

A specific "aryl" may be a monovalent group having one hydrogen removed from the above-mentioned "aryl ring". For example, monocyclic phenyl, bicyclic biphenylyl (2-biphenylyl, 3-biphenylyl or 4-biphenylyl), fused bicyclic naphthyl (1-naphthyl or 2-naphthyl), tricyclic terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl or p-terphenyl-4-yl), fused tricyclic acenaphthylene-(1-, 3-, 4- or 5-), fluoren-(1-, 2-, 3-, 4- or 9-)yl, phenalen-(1- or 2-)yl, phenanthren-(1-, 2-, 3-, 4- or 9-)yl or anthracen-(1-, 2- or 9-)yl, a tetracyclic quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl or m-quaterphenyl), a fused tetracyclic quaternary ... 5- or 6-) etc. In addition, monovalent groups of spirofluorene can be mentioned.

In addition, aryl as a second substituent also includes a structure in which the aryl is substituted with one or more groups selected from the group consisting of aryl such as phenyl (a specific example is a group described above), alkyl such as methyl (a specific example is a group described below), and cycloalkyl such as cyclohexyl or adamantyl (a specific example is a group described below).

As an example, a group in which the 9th position of fluorenyl as a second substituent is substituted with an aryl group such as phenyl, an alkyl group such as methyl, or a cycloalkyl group such as cyclohexyl or adamantyl may be mentioned.

"Arylene" is, for example, arylene having 6 to 30 carbon atoms, preferably arylene having 6 to 20 carbon atoms, arylene having 6 to 16 carbon atoms, arylene having 6 to 12 carbon atoms, or arylene having 6 to 10 carbon atoms.

A specific "arylene" may include, for example, a divalent group in which one hydrogen is removed from the above-mentioned "aryl" (a monovalent group).

"Heteroaryl" is, for example, a heteroaryl having 2 to 30 carbon atoms, preferably a heteroaryl having 2 to 25 carbon atoms, a heteroaryl having 2 to 20 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, or a heteroaryl having 2 to 10 carbon atoms. "Heteroaryl" contains, as a ring constituent atom, at least one, preferably 1 to 5, heteroatoms selected from oxygen, sulfur, and nitrogen, in addition to carbon.

A specific "heteroaryl" may include a monovalent group in which one hydrogen is removed from the above-described "heteroaryl ring". For example, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, benzoimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiinyl, phenoxadinyl, phenothiazinyl, phenazinyl, phenaxacillinyl, Examples thereof include indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, naphthobenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, naphthobenzothienyl, a monovalent group of a benzophosphol oxide ring, a monovalent group of a dibenzophosphol oxide ring, furazanyl, thianthrenyl, indolocarbazolyl, benzoindolocarbazolyl, dibenzoindolocarbazolyl, imidazolinyl or oxazolinyl. In addition, a monovalent group of spiro[fluorene-9,9'-xanthene], a monovalent group of spirobi[silafluorene], and a monovalent group of benzoselenophene can be mentioned.

In addition, heteroaryl as a second substituent also includes a structure in which the heteroaryl is substituted with one or more groups selected from the group consisting of aryl such as phenyl (a specific example is a group described above), alkyl such as methyl (a specific example is a group described below), and cycloalkyl such as cyclohexyl or adamantyl (a specific example is a group described below).

As an example, a group in which the 9th position of carbazolyl as a second substituent is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl is mentioned. In addition, a group in which a nitrogen-containing heteroaryl such as pyridyl, pyrimidinyl, triazinyl, or carbazolyl is further substituted with phenyl or biphenylyl is also included in the heteroaryl as a second substituent.

"Heteroarylene" is, for example, a heteroarylene having 2 to 30 carbon atoms, and preferably includes a heteroarylene having 2 to 25 carbon atoms, a heteroarylene having 2 to 20 carbon atoms, a heteroarylene having 2 to 15 carbon atoms, or a heteroarylene having 2 to 10 carbon atoms. In addition, "heteroarylene" is, for example, a divalent group such as a heterocycle containing 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen in addition to carbon as ring constituent atoms.

A specific "heteroarylene" may include, for example, a divalent group in which one hydrogen is removed from the above-mentioned "heteroaryl" (a monovalent group).

"Diarylamino" is an amino substituted with two aryls, and for details on this aryl, the description of "aryl" mentioned above can be cited.

“Diheteroarylamino” is an amino group substituted with two heteroaryls, and details of this heteroaryl can be referred to the description of “heteroaryl” mentioned above.

"Arylheteroarylamino" is an amino group substituted with aryl and heteroaryl, and details of the aryl and heteroaryl can be referred to the description of "aryl" and "heteroaryl" mentioned above.

In the diarylamino as the first substituent, two aryls may be bonded to each other via a linking group, in the diheteroarylamino as the first substituent, two heteroaryls may be bonded to each other via a linking group, and the aryl and heteroaryl of the arylheteroarylamino as the first substituent may be bonded to each other via a linking group. Here, "bonding via a linking group" means, as shown below, that two phenyls of diphenylamino form a bond via a linking group. In addition, this description also applies to diheteroarylamino and arylheteroarylamino formed by aryl or heteroaryl.

Specific examples of linking groups include ＞O, ＞NR ^X , ＞C(-R ^X ) ₂ , -C(-R ^X )=C(-R ^X )-, ＞Si(-R ^X ) ₂ , ＞S, ＞CO, ＞CS, ＞SO, ＞SO ₂ , ＞SeO, ＞SeO ₂ , ＞PO, ＞B(-R ^X ) and ＞Se. Each R ^X is independently alkyl, cycloalkyl, aryl or heteroaryl, and these may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. In addition, two R X in each of ＞C(-R ^X ) ₂ , -C(-R ^X )=C(-R ^X )-, ＞Si(-R ^X ) ₂ may be bonded to each other via a single bond or a linking group X ^Y to form a ^ring . X ^Y includes ＞O, ＞NR ^Y , ＞C(-R ^Y ) ₂ , ＞Si(-R ^Y ) ₂ , ＞S, ＞CO, ＞CS, ＞SO, ＞SO ₂ and ＞Se, and R ^Y is each independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. However, when X ^Y is ＞C(-R ^Y ) ₂ and ＞Si(-R ^Y ) ₂ , two R ^Y do not combine to form an additional ring. In addition, as a linking group, alkenylene can also be mentioned. Any hydrogen of the alkenylene may be each independently substituted with R ^2X , and R ^2X is each independently alkyl, cycloalkyl, substituted silyl, aryl and heteroaryl, which may be substituted with alkyl, cycloalkyl, substituted silyl or aryl. -The two R ^X in -C(-R ^X )=C(-R ^X )- may be bonded to each other to form an aryl ring (such as a benzene ring) or a heteroaryl ring together with the C=C to which they are bonded. That is, -C(-R ^X )=C(-R ^X )- may become arylene (such as 1,2-phenylene) or heteroarylene.

In addition, in cases where it is simply described as "diarylamino", "diheteroarylamino" or "arylheteroarylamino" in this specification, unless specifically stated otherwise, it is assumed that the explanations "two aryls of the diarylamino may be bonded to each other via a linking group", "two heteroaryls of the diheteroarylamino may be bonded to each other via a linking group" and "the aryl and heteroaryl of the arylheteroarylamino may be bonded to each other via a linking group" are added, respectively.

"Diarylboryl" is a boryl substituted with two aryls, and the details of this aryl can be cited from the description of the above-mentioned "aryl". In addition, these two aryls may be bonded via a single bond or a linking group (e.g., -CH=CH-, -CR=CR-, -C≡C-, ＞NR, ＞O, ＞S, ＞CO, ＞C=S, ＞S=O, ＞S(=O) ₂ , ＞Se(=O), ＞Se(=O) ₂ , ＞P(=O), ＞B(-R), ＞C(-R) ₂ , ＞Si(-R) ₂ or ＞Se). Here, R of the -CR=CR-, R of ＞NR, R of ＞B(-R), R of ＞C(-R) ₂ and R of ＞Si(-R) are aryl, heteroaryl, diarylamino, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy or aryloxy, and one or more hydrogens in R may be further substituted with aryl, heteroaryl, alkyl, alkenyl, alkynyl or cycloalkyl. In addition, two adjacent R's may be combined to form a ring, forming cycloalkylene, arylene and heteroarylene. Details of the substituents listed herein may be cited from the descriptions of "aryl", "arylene", "heteroaryl", "heteroarylene", and "diarylamino" described above, and the descriptions of "alkyl", "alkenyl", "alkynyl", "cycloalkyl", "cycloalkylene", "alkoxy", and "aryloxy" described below. In addition, when simply described as "diarylboryl" in this specification, unless otherwise specified, it is understood that the description that "two aryls of the diarylboryl may be bonded to each other via a single bond or a linking group" is added.

"Alkyl" may be either straight-chain or branched-chain, for example, straight-chain alkyl having 1 to 24 carbon atoms or branched-chain alkyl having 3 to 24 carbon atoms, and preferably alkyl having 1 to 18 carbon atoms (branched-chain alkyl having 3 to 18 carbon atoms), alkyl having 1 to 12 carbon atoms (branched-chain alkyl having 3 to 12 carbon atoms), alkyl having 1 to 6 carbon atoms (branched-chain alkyl having 3 to 6 carbon atoms), alkyl having 1 to 5 carbon atoms (branched-chain alkyl having 3 to 5 carbon atoms), alkyl having 1 to 4 carbon atoms (branched-chain alkyl having 3 to 4 carbon atoms), etc.

Specific "alkyl"s include, for example, methyl, ethyl, n-propyl, isopropyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1,1,2,2-tetramethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-ethylbutyl, 1,1-dimethylbutyl, 3,3-dimethylbutyl, 1,1-diethylbutyl, 1-ethyl-1-methylbutyl, 1-propyl-1-methylbutyl, 1,1,3-trimethylbutyl, 1-ethyl-1,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, t-pentyl(t-amyl), 1-methylpentyl, 2-propylpentyl, 1,1-dimethylpentyl, 1-Ethyl-1-methylpentyl, 1-propyl-1-methylpentyl, 1-butyl-1-methylpentyl, 1,1,4-trimethylpentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 1,1-dimethylhexyl, 1-ethyl-1-methylhexyl, 1,1,5-trimethylhexyl, 3,5,5-trimethylhexyl, n-heptyl, 1-methylheptyl, 1-hexylheptyl, 1,1-dimethylheptyl, 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, n-octyl, t-octyl (1,1,3,3-tetramethylbutyl), 1,1-dimethyloctyl, n-nonyl, n-decyl, 1-methyldecyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl or n-eicosyl.

"Alkylene" is a divalent group obtained by removing the hydrogen of any one of the "alkyl" groups, examples of which include methylene, ethylene, and propylene.

For "alkenyl", reference can be made to the explanation of "alkyl" mentioned above, and it is a group in which a C-C single bond in the "alkyl" structure is replaced with a C=C double bond, and also includes a group in which not only one but two or more single bonds are replaced with double bonds (also called alkadien-yl or alkatrien-yl).

"Alkenylene" is a divalent group obtained by removing the hydrogen of any one of "alkenyl", and an example is vinylene.

For "alkynyl", reference can be made to the explanation of "alkyl" mentioned above, and it is a group in which a C-C single bond in the "alkyl" structure is replaced with a C≡C triple bond, and also includes a group in which not only one but two or more single bonds are replaced with triple bonds (also called alkadiyn-yl or alkatriyn-yl).

"Cycloalkyl" is, for example, cycloalkyl having 3 to 24 carbon atoms, preferably cycloalkyl having 3 to 20 carbon atoms, cycloalkyl having 3 to 16 carbon atoms, cycloalkyl having 3 to 14 carbon atoms, cycloalkyl having 3 to 12 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, cycloalkyl having 5 to 8 carbon atoms, cycloalkyl having 5 to 6 carbon atoms, or cycloalkyl having 5 carbon atoms.

Specific "cycloalkyl"s are, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl or C1-5 or C1-4 alkyl (especially methyl) substituents thereof, bicyclo[1.1.0]butyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.1]heptyl(norbornyl), bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphthalenyl or decahydroazulenyl.

"Cycloalkylene" is, for example, cycloalkylene having 3 to 24 carbon atoms, preferably cycloalkylene having 3 to 20 carbon atoms, cycloalkylene having 3 to 16 carbon atoms, cycloalkylene having 3 to 14 carbon atoms, cycloalkylene having 3 to 12 carbon atoms, cycloalkylene having 5 to 10 carbon atoms, cycloalkylene having 5 to 8 carbon atoms, cycloalkylene having 5 to 6 carbon atoms, or cycloalkylene having 5 carbon atoms.

A specific "cycloalkylene" may include, for example, a structure in which one hydrogen is removed from the above-mentioned "cycloalkyl" (a monovalent group) to form a divalent group.

"Cycloalkenyl" is a group having a structure in which one or more sets of single bonds between two carbons in the above-mentioned "cycloalkyl" become double bonds (for example, a group in which -CH ₂ -CH ₂ - is replaced with -CH=CH-), and includes groups that do not correspond to aryl. Specific examples include 1-cyclohexenyl and 1-cyclopentenyl.

"Alkoxy" is a group represented by "Alk-O-(Alk is alkyl)", and for details on this alkyl, the description of "alkyl" mentioned above can be cited.

"Aryloxy" is a group represented by "Ar-O-(Ar is aryl)", and for details on this aryl, the description of "aryl" mentioned above can be cited.

“Substituted silyl” is a silyl substituted with one or more of, for example, aryl, alkyl and cycloalkyl, preferably triarylsilyl, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl or alkyldicycloalkylsilyl.

"Triarylsilyl" is a silyl group substituted with three aryls, and the details of this aryl can be referred to the description of "aryl" mentioned above.

Specific "triarylsilyls" include, for example, triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl or trinaphthylsilyl.

"Trialkylsilyl" is a silyl group substituted with three alkyls, and for details on this alkyl, the description of "alkyl" mentioned above can be cited.

Specific "trialkylsilyls" include, for example, trimethylsilyl, triethylsilyl, tri-n-propylsilyl, triisopropylsilyl, tri-n-butylsilyl, triisobutylsilyl, tri-s-butylsilyl, tri-t-butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, s-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, n-propyldiethylsilyl, isopropyldiethylsilyl, n-butyldiethylsilyl, s-butyldiethylsilyl, t-butyldiethylsilyl, methyldi-n-propylsilyl, ethyldi-n-propylsilyl, n-butyldi-n-propylsilyl, s-butyldi-n-propylsilyl, t-butyldi-n-propylsilyl, methyldiisopropylsilyl, Examples include ethyldiisopropylsilyl, n-butyldiisopropylsilyl, s-butyldiisopropylsilyl, and t-butyldiisopropylsilyl.

"Tricycloalkylsilyl" is a silyl group substituted with three cycloalkyls, and for details on this cycloalkyl, the description of "cycloalkyl" mentioned above can be cited.

Specific "tricycloalkylsilyl" includes, for example, tricyclopentylsilyl or tricyclohexylsilyl.

“Dialkylcycloalkylsilyl” is a silyl group substituted with two alkyls and one cycloalkyl, and for details of the alkyls and cycloalkyls, the description of “alkyl” and “cycloalkyl” mentioned above can be cited.

“Alkyldicycloalkylsilyl” is a silyl group substituted with one alkyl and two cycloalkyl, and for details of the alkyl and cycloalkyl, the description of “alkyl” and “cycloalkyl” mentioned above can be cited.

“Halogen” is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, more preferably fluorine or chlorine, and fluorine is even more preferred.

When cyano or halogen is substituted, a form in which all or part of the hydrogen of the aryl ring or heteroaryl ring in the structure is substituted with cyano or halogen is also preferred.

The substituent represented by formula (A30) has the following structure.

Among the foods (A30),

Ak is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkyl or substituted or unsubstituted cycloalkenyl, and one or more -CH ₂ - among the alkyl, cycloalkyl and cycloalkenyl may be substituted with -O- or -S-,

R ^Ak is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl, or a substituted or unsubstituted cycloalkyl, and R ^Ak may be bonded to Ak by a linking group or a single bond, and * represents a bonding position.

In formula (A30), since Ak is the above substituent and does not conjugate with the unshared electron pair on N, the unshared electron pair can be conjugated with the π electron of the bonding site, and a larger wavelength change is possible compared to the case where aryl, etc. is present at the same position. In addition, the same applies to the influence on the multiple resonance effect, and a larger improvement in thermally activated delayed fluorescence (TADF) properties is possible.

R ^Ak is preferably an aryl which may be substituted with alkyl or cycloalkyl, a heteroaryl which may be substituted with alkyl or cycloalkyl, an alkyl or cycloalkyl, more preferably an aryl which may be substituted with alkyl, a heteroaryl which may be substituted with alkyl, an alkyl or cycloalkyl, even more preferably an aryl which may be substituted with alkyl, and particularly preferably phenyl which may be substituted with methyl.

In formula (A30), Ak is preferably an alkyl having 1 to 6 carbon atoms or a cycloalkyl having 3 to 14 carbon atoms, more preferably an alkyl having 1 to 4 carbon atoms or a cycloalkyl having 3 to 8 carbon atoms, still more preferably an alkyl having 1 to 4 carbon atoms, and particularly preferably methyl.

R ^Ak and Ak may be the same or different, and it is preferable that they be different.

R ^Ak may be bonded to Ak by a linking group or a single bond. The linking group at this time can include >O, >S or >Si(-R) ₂ . R of >Si(-R) ₂ is hydrogen, aryl having 6 to 12 carbon atoms, alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 14 carbon atoms. Examples of structures in which R ^Ak is bonded to Ak by a linking group or a single bond include the following.

In each of the above formulas, * indicates a bonding position.

＜When two groups that bind to the same atom bind to each other＞

In the present specification, when two groups bonded to the same atom may be bonded to each other to form a ring, they may be bonded by a single bond or a linking group (these are collectively referred to as a linking group), and the linking group may be -CH ₂ -CH ₂ -, -CHR-CHR-, -CR ₂ -CR ₂ -, -CH=CH-, -CR=CR-, -C≡C-, -N(-R)-, -O-, -S-, -C(-R) ₂ -, -C(=O)-, -C(=S)-, -S(=O)-, -S(=O) ₂ -, -Se(=O)-, -Se(=O) ₂ -, -P(=O)-, -B(-R)-, -Si(-R) ₂ - or -Se-, and examples thereof include the following structures.

In addition, R of the above -CHR-CHR-, R of -CR ₂ -CR ₂ -, R of -CR=CR-, R of -N(-R)-, R of -C(-R) ₂ -, R of -B(-R)- and R of -Si(-R) ₂ - are each independently hydrogen, aryl which may be substituted with alkyl or cycloalkyl, heteroaryl which may be substituted with alkyl or cycloalkyl, alkyl which may be substituted with cycloalkyl, alkenyl which may be substituted with alkyl or cycloalkyl, alkynyl which may be substituted with alkyl or cycloalkyl, or cycloalkyl which may be substituted with alkyl or cycloalkyl. In addition, two adjacent R's may be combined to form a ring, thereby forming cycloalkylene, arylene, or heteroarylene.

As a bonding group, -CR=CR-, -N(-R)-, -O-, -S-, -C(-R) ₂ -, -Si(-R) ₂ - and -Se- are preferable as a single bond or a linking group, -CR=CR-, -N(-R)-, -O-, -S- and -C(-R) ₂ - are more preferable as a single bond or a linking group, -CR=CR-, -N(-R)-, -O- and -S- are even more preferable as a single bond or a linking group, and a single bond is most preferable.

The positions at which two R's are bonded by the bonding group are not particularly limited as long as they are bondable positions, but bonding at the most adjacent positions is preferable, and for example, when the two groups are phenyl, bonding at the ortho (2nd position) positions based on the bonding position of "C" or "Si" in phenyl (1st position) is preferable (see the structural formula above).

＜Stereoisomers, etc.＞

The polycyclic aromatic compound of the present invention may exist as an enantiomer or a diastereomer depending on the type of substituent, etc., and regardless of the described structural formula, all pure forms of any stereoisomer, any mixture of stereoisomers, racemates, etc. are all included within the scope of the present invention.

1. Polycyclic aromatic compound of the present invention

The polycyclic aromatic compound of the present invention is represented by formula (1) and includes at least one partial structure represented by formula (X-a-1) and at least one partial structure represented by formula (X-b-1).

In equation (1),

Ring A, ring B and ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

Among the formulas (X-a-1),

X ^a is C, Si, Ge or Sn, and the AR1 ring, AR2 ring, AR3 ring and AR4 ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and any two selected from the group consisting of the AR1 ring, AR2 ring, AR3 ring and AR4 ring may be connected to each other by a single bond or a linking group,

One or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring are bonded to a ring constituting atom of an aryl ring or heteroaryl ring in ring A, ring B or ring C through a single bond, or

Is bonded to ring A, ring B or ring C, or is bonded to an aryl ring or heteroaryl ring of ring D, ring E or AR5 in formula (X-b-1) that shares one ring with ring A, ring B or ring C, through a single bond,

Sharing a ring with Ring A, Ring B or Ring C, or

It is bonded to ring A, ring B or ring C, or shares a ring with ring D, ring E or AR5 among formula (X-b-1) which shares a ring with ring A, ring B or ring C,

Among the formulas (X-b-1),

D ring and E ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

X ^b is a divalent group having an AR5 ring as described below, >O or >S,

The AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR5 ring may be connected to the D ring and/or the E ring by a single bond or a connecting group.

One or two selected from the group consisting of D ring, E ring and AR5 ring,

Is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the A ring, B ring or C ring through a single bond, or

Is bonded to an aryl ring or heteroaryl ring in the AR1 ring, AR2 ring, AR3 ring or AR4 ring in formula (X-a-1) which is bonded to ring A, ring B or ring C, or shares one ring with ring A, ring B or ring C, or is bonded through a single bond,

Sharing a ring with Ring A, Ring B or Ring C, or

It shares a ring with an AR1 ring, AR2 ring, AR3 ring or AR4 ring among formula (X-a-1) which is bound to ring A, ring B or ring C, or shares a ring with ring A, ring B or ring C,

In the above structure, one or more hydrogen atoms may be replaced with deuterium.

The present inventors have found that the polycyclic aromatic compound of the present invention, in which an aromatic ring is connected by oxygen, has a large HOMO-LUMO gap (band gap Eg in a thin film) and high triplet energy. It is thought that this is because the ring including a heteroatom has low aromaticity, so that the decrease in the HOMO-LUMO gap due to the expansion of the conjugated system is suppressed, and a large HOMO-LUMO gap can be obtained by suppressing the expansion of the conjugated system by utilizing distortion within the molecule.

In addition, the polycyclic aromatic compound containing a heteroatom according to the present invention is a material having high triplet energy, and is useful as a host compound of a phosphorescent organic EL device or an organic EL device using thermally activated delayed fluorescence, an electron-blocking layer (electron-blocking layer) or a hole-blocking layer (hole-blocking layer) adjacent to a light-emitting layer, an electron-transporting layer or a hole-transporting layer. Furthermore, since these polycyclic aromatic compounds can arbitrarily move the energy of HOMO and LUMO by introducing a substituent, it is possible to optimize the ionization potential or electron affinity depending on the surrounding materials.

＜Explanation of ring structure in compounds＞

In formula (1), "A", "B", and "C" in the circle are symbols representing a ring structure represented by the circle, in formula (Xa-1), "AR1", "AR2", "AR3", and "AR4" are symbols representing a ring structure represented by the circle, and in formula (Xb-1), "D" and "E" are symbols representing a ring structure represented by the circle. In addition, "AR5" in X ^b described below is a symbol representing a ring structure represented by the circle.

The A ring, B ring, C ring, D ring, E ring, AR1 ring, AR2 ring, AR3 ring, AR4 ring and AR5 ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring.

The A ring forms a trivalent group having bonds to three consecutive atoms (preferably carbon) on the aryl ring or heteroaryl ring in the structure. The A ring is bonded to two O (oxygen) atoms and B (boron) atoms with these three bonds. When the A ring is bonded to an AR1 ring, an AR2 ring, an AR3 ring, an AR4 ring, an AR5 ring, a D ring or an E ring at another site as described below, or shares an aryl ring or a heteroaryl ring with the AR1 ring, an AR2 ring, an AR3 ring, an AR4 ring, an AR5 ring, a D ring or an E ring, the A ring may be a tetravalent or pentavalent group. The ring having the atom having the above-mentioned bond in the A ring as a ring constituent atom is preferably a 5-membered ring or a 6-membered ring, and is more preferably a 6-membered ring. This ring may be fused with another ring. Examples of six-membered rings include a benzene ring, a pyridine ring, a pyrazine ring, and a pyrimidine ring. Examples of six-membered rings fused with another ring include a naphthalene ring, a quinoline ring, a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring. Examples of five-membered rings include a furan ring, a thiophene ring, a pyrrole ring, and a thiazole ring. Examples of five-membered rings fused with another ring include a benzofuran ring, a benzothiophene ring, and an indole ring. In addition, an indene ring can also be cited as a condensed ring.

Among the aryl ring or heteroaryl ring in the A ring, a benzene ring is preferable.

Both the B ring and the C ring form a divalent group having bonding hands at two adjacent atoms (preferably carbon) on the aryl ring or heteroaryl ring in the structure. The B ring is bonded to O (oxygen) and B (boron) by the two bonding hands, and the C ring is bonded to O (oxygen) and B (boron) by the two bonding hands. The B ring and the C ring are each bonded to an AR1 ring, an AR2 ring, an AR3 ring, an AR4 ring, an AR5 ring, a D ring or an E ring at another site as described below, or when they share an aryl ring or a heteroaryl ring with an AR1 ring, an AR2 ring, an AR3 ring, an AR4 ring, an AR5 ring, a D ring or an E ring, the B ring and the C ring may each be a trivalent or tetravalent group. In each of the B ring and the C ring, the ring having the atoms having the above two bonding hands as ring constituent atoms is preferably a 5-membered ring or a 6-membered ring, and is more preferably a 6-membered ring. This ring may be fused with another ring. Examples of 6-membered rings include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, etc. Examples of a 6-membered ring fused with another ring include a naphthalene ring, a quinoline ring, a benzofuran ring, a benzothiophene ring, an indole ring, a benzoselenophene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a dibenzoselenophene ring, etc. Examples of 5-membered rings include a furan ring, a thiophene ring, a pyrrole ring, a thiazole ring, a selenophene ring, etc. Examples of five-membered rings fused with another ring include the benzofuran ring, benzothiophene ring, indole ring, and benzoselenophene ring. Another example of a fused ring is the indene ring.

Among the aryl ring or heteroaryl ring in the B ring and the C ring, a benzene ring, a benzofuran ring, a benzothiophene ring or a benzoselenophene ring is each independently preferable, and a benzene ring, a benzofuran ring or a benzothiophene ring is more preferable.

Both the D ring and the E ring form a divalent group having bonding hands at two adjacent atoms (preferably carbon) on the aryl ring or heteroaryl ring in their structure. The D ring is bonded to X ^b and the E ring with the two bonding hands, and the E ring is bonded to X ^b and the D ring with the two bonding hands. When the D ring and the E ring are each bonded to the AR5 ring at different sites, the D ring and the E ring may each become a trivalent group. In addition, when the D ring and the E ring are each bonded to an AR1 ring, AR2 ring, AR3 ring, AR4 ring, A ring, B ring or C ring at different sites as described below, or when they share an aryl ring or heteroaryl ring with an AR1 ring, AR2 ring, AR3 ring, AR4 ring, A ring, B ring or C ring, the D ring and the E ring may each become a trivalent or tetravalent group. In each of the D ring and the E ring, the ring having the atoms having the above two bonding hands as ring constituent atoms is preferably a 5-membered ring or a 6-membered ring, and is more preferably a 6-membered ring. This ring may be fused with another ring. Examples of 6-membered rings include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, etc. Examples of a 6-membered ring fused with another ring include a naphthalene ring, a quinoline ring, a benzofuran ring, a benzothiophene ring, an indole ring, a benzoselenophene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a dibenzoselenophene ring, etc. Examples of 5-membered rings include a furan ring, a thiophene ring, a pyrrole ring, a thiazole ring, a selenophene ring, etc. Examples of five-membered rings fused with another ring include the benzofuran ring, benzothiophene ring, indole ring, and benzoselenophene ring.

Among the aryl ring or heteroaryl ring in the D ring and E ring, a benzene ring or a pyridine ring is independently preferred, and a benzene ring is more preferred.

The AR1 ring, AR2 ring, AR3 ring, AR4 ring and AR5 ring all form a monovalent group having a bonding hand to one atom (preferably carbon) on the aryl ring or heteroaryl ring in the structure. The AR1 ring, AR2 ring, AR3 ring and AR4 ring are each bonded to X ^a by one bonding hand. The AR5 ring may be a divalent group when the AR1 ring, AR2 ring, AR3 ring and AR4 ring, each of which is bonded to nitrogen by one bonding hand, is connected to any one of the other AR1 ring, AR2 ring, AR3 ring and AR4 rings by a single bond or a connecting group as described below. In addition, among the AR1 ring, AR2 ring, AR3 ring and AR4 ring, any one of the following (1) or (2) is a divalent, trivalent or tetravalent group as described below.

(1) It is bonded to a ring constituent atom of an aryl ring or heteroaryl ring among the A ring, B ring, C ring, D ring, E ring or AR5 ring through a single bond or linking group;

(2) Sharing a ring with the A ring, B ring, C ring, D ring, E ring or AR5 ring.

When the AR5 ring is bonded to the D ring or the E ring at another site, the AR5 ring may be a divalent or trivalent group. In addition, when the AR5 ring is bonded to the AR1 ring, AR2 ring, AR3 ring, AR4 ring, A ring, B ring or C ring as described below, or shares an aryl ring or heteroaryl ring with the AR1 ring, AR2 ring, AR3 ring, AR4 ring, A ring, B ring or C ring, the AR5 ring may be a divalent, trivalent or tetravalent group.

In each of the AR1 ring, AR2 ring, AR3 ring, AR4 ring, and AR5 ring, the ring having the atom having the above-mentioned bond as a ring constituent atom is preferably a 5-membered ring or a 6-membered ring, and is more preferably a 6-membered ring. This ring may be fused with another ring. Examples of 6-membered rings include a benzene ring, a pyridine ring, a pyrazine ring, and a pyrimidine ring. Examples of a 6-membered ring fused with another ring include a naphthalene ring, a quinoline ring, a benzofuran ring, a benzothiophene ring, an indole ring, a benzoselenophene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, and a dibenzoselenophene ring. Examples of 5-membered rings include a furan ring, a thiophene ring, a pyrrole ring, a thiazole ring, and a selenophene ring. Examples of five-membered rings fused with another ring include the benzofuran ring, benzothiophene ring, indole ring, and benzoselenophene ring.

Among the aryl ring or heteroaryl ring in each of the AR1 ring, AR2 ring, AR3 ring and AR4 ring, a benzene ring, a benzofuran ring, a benzothiophene ring or a benzoselenophene ring is each independently preferable, and a benzene ring is more preferable. Among the aryl ring or heteroaryl ring in the AR5 ring, a benzene ring, a benzofuran ring, a benzothiophene ring or a benzoselenophene ring is each independently preferable, and a benzene ring is more preferable.

＜Description of Partial Structure and Overall Structure＞

At least one partial structure represented by formula (X-a-1) is included in the polycyclic aromatic compound of the present invention, and it is preferable that one is included.

In formula (Xa-1), X ^a is C, Si, Ge or Sn, and X ^a is preferably C or Si, and Si is more preferable.

In formula (Xa-1), the AR1 ring, AR2 ring, AR3 ring and AR4 ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR1 ring, AR2 ring, AR3 ring and AR4 ring may be connected to another AR1 ring, AR2 ring, AR3 ring or AR4 ring by a single bond or a connecting group. Here, when it is said to be connected, it means that there is a connection by an additional single bond or connecting group in addition to the connection via X ^a . In the case where such a connection exists, it is preferable that among the AR1 ring, AR2 ring, AR3 ring or AR4 ring, the AR1 ring and the AR2 ring are connected, or the AR1 ring and the AR2 ring, and the AR3 ring and the AR4 ring are each connected. In this case, it is preferable that they are connected by a single bond, >O or >S, and it is more preferable that they are connected by a single bond.

From the viewpoint of manufacturing higher quantum efficiency and long-life devices, when X ^a is Si, it is more preferable that two or more of the AR1 ring, AR2 ring, AR3 ring, and AR4 ring are connected to each other. In particular, it is preferable that they are connected by a single bond. When X ^a is C, it is more preferable that no two of the AR1 ring, AR2 ring, AR3 ring, and AR4 ring are connected to each other.

At least one partial structure represented by formula (X-b-1) is included in the polycyclic aromatic compound of the present invention, and it is preferable that one is included.

In formula (Xb-1), X ^b is a divalent group represented by formula (Xb-R5), >O or >S.

In the formula (Xb-R5), two #s represent bonding positions with the D ring and the E ring, respectively.

From the viewpoint of high carrier transport and good carrier balance, it is desirable that X ^b be a divalent group represented by the formula (Xb-R5). That is, it is desirable that the formula (Xb-1) is the following formula (Xb-1-R5).

The AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR5 ring may be connected to the D ring and/or the E ring via a single bond or a linking group. Specific examples of the linking group include >O, >NR ^de , >C(-R ^de ) ₂ , >Si(-R ^de ) ₂ , >S, >CO, >CS, >SO, >SO ₂ and >Se. Each R ^de is independently alkyl, cycloalkyl, aryl or heteroaryl, and these may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. In addition, in each of >C(-R ^de ) ₂ and >Si(-R ^de ) _{2 ,} two R ^de may be connected to each other to form a ring. When the AR5 ring is connected to the D ring and/or the E ring by a single bond or a connecting group, it is preferable that it is connected by a single bond, >O, >C(-Me) ₂ , >C(-Ph) ₂ , >S or >Se. Additionally, in >C(-Ph) _{2 ,} two Ph's may be connected to each other by a single bond to form a ring.

The partial structure represented by formula (X-a-1) and the partial structure represented by formula (X-b-1) are each connected by bonding or ring sharing with the A ring, B ring or C ring in formula (1) and the other partial structure, thereby forming the partial structure of the polycyclic aromatic compound represented by formula (1).

Specifically, in formula (X-a-1), one or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring are:

Is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the A ring, B ring or C ring through a single bond;

Or is bonded to an aryl ring or heteroaryl ring of the D ring, E ring or AR5 ring in formula (X-b-1) which is bonded to ring A, ring B or ring C, or shares one ring with ring A, ring B or ring C, through a single bond;

Sharing a ring with Ring A, Ring B or Ring C; or

It shares a ring with the D ring, E ring or AR5 ring among the formulas (X-b-1) which is bound to the A ring, B ring or C ring, or shares a ring with the A ring, B ring or C ring.

In addition, one or two selected from the group consisting of D ring, E ring and AR5 ring in formula (X-b-1) are:

Is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the A ring, B ring or C ring through a single bond;

Or is bonded to an aryl ring or heteroaryl ring among the AR1 ring, AR2 ring, AR3 ring or AR4 ring in formula (X-a-1) which is bonded to ring A, ring B or ring C, or shares one ring with ring A, ring B or ring C, through a single bond;

Sharing a ring with Ring A, Ring B or Ring C; or

It shares a ring with an AR1 ring, an AR2 ring, an AR3 ring or an AR4 ring among formula (X-a-1) which is bound to an A ring, a B ring or a C ring, or shares a ring with an A ring, a B ring or a C ring.

When an AR1 ring, AR2 ring, AR3 ring or AR4 ring is bonded to an aryl ring or heteroaryl ring ring atom in ring A, ring B or ring C through a single bond or a partial structure represented by formula (X-b-1), it is preferable that it is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the ring (AR1 ring, AR2 ring, AR3 ring or AR4 ring).

When the D ring, E ring or AR5 ring is bonded to an aryl ring or heteroaryl ring ring atom in the A ring, B ring or C ring through a single bond or a partial structure represented by the formula (X-a-1), it is preferable that it is bonded to a ring constituent atom of the aryl ring or heteroaryl ring in the ring (D ring, E ring or AR5 ring).

A polycyclic aromatic compound represented by formula (1) which includes one partial structure represented by formula (X-a-1) and one partial structure represented by formula (X-b-1), wherein one of the rings in formula (X-a-1) and one of the rings in formula (X-b-1) are bonded to a ring constituent atom of an aryl ring or heteroaryl ring in another ring via a single bond, the following are examples of structures.

As described above, for example, a structure in which ring B and ring AR1 are bonded by a single bond, and ring C and ring D are bonded by a single bond is represented as B-AR1C-D, and a structure in which ring B and ring D are bonded by a single bond, and ring AR5 and ring AR1 are bonded by a single bond is represented as B-DAR5-AR1.

According to this notation, other examples of structures in which each partial structure is bonded to an aryl ring or heteroaryl ring in a single-bonded A ring, B ring or C ring, or an aryl ring or heteroaryl ring in another partial structure, include the structures below.

A-AR1B-D

A-AR1B-AR5

A-DB-AR1

A-AR5B-AR1

B-AR1C-AR5

A-AR1AR2-D

A-AR1AR3-D

A-AR1AR2-AR5

A-AR1AR3-AR5

A-DE-AR1

A-DAR5-AR1

A-AR5D-AR1

B-AR1AR2-D

B-AR1AR3-D

B-AR1AR2-AR5

B-AR1AR3-AR5

B-DE-AR1

B-AR5D-AR1

When each partial structure represented by formula (X-a-1) and formula (X-b-1) is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in another ring through a single bond, the substitution position at which the conjugated system becomes cross-conjugated is preferable.

In this specification, when it is said that rings A, B, C, AR1, AR2, AR3, AR4, AR5, D, and E are shared, it means that the target rings are unified.

As an example of such a structure, an example of the structure of a polycyclic aromatic compound represented by formula (1) including one partial structure represented by formula (X-a-1) and one partial structure represented by formula (X-b-1) is shown below.

For example, the structure represented by the following formula (AAR5DAR1) is a structure in which the A ring and the AR5 ring share a ring, and the AR1 ring and the D ring share a ring.

Similarly, for example, the structure represented by the following formula (AAR1CAR5) represents a structure in which the A ring and the AR1 ring share a ring, while the AR5 ring and the C ring share a ring.

Similarly, for example, the structure represented by the following formula (AAR1AR3AR5) represents a structure in which the A ring and the AR1 ring share a ring, and the AR5 ring and the AR3 ring share a ring.

As above, for example, a structure represented as (AAR5DAR1) represents a structure in which the A ring and the AR5 ring share a ring, while the D ring and the AR1 ring share a ring.

As examples of structures in which each substructure is joined by sharing a ring according to this notation, in addition to the three examples above, the structures below can be cited.

AAR1BD

AAR1BAR5

ADBAR1

AAR5BAR1

BAR1CD

AAR1AR2D

AAR1AR3D

AAR1AR2AR5

ADEAR1

ADAR5AR1

BAR1AR2D

BAR1AR3D

BAR1AR2AR5

BAR1AR3AR5

BDEAR1

BDAR5AR1

BAR5DAR1

The polycyclic aromatic compound of the present invention may include a partial structure that shares a ring and a partial structure that is bonded through a single bond or the like. As an example of such a structure, an example of the structure of a polycyclic aromatic compound represented by formula (1) that includes one partial structure represented by formula (X-a-1) and one partial structure represented by formula (X-b-1) is shown below.

For example, in the structure represented by the following formula (B-AR1CD), the aryl ring or heteroaryl ring in the D ring in (X-b-1) is bonded to a ring constituent atom of the aryl ring or heteroaryl ring in the C ring through a single bond, and the B ring and the AR1 ring share the ring.

As examples of other structures according to the above notation, the following structures can be cited.

A-AR1BD

A-AR1BAR5

A-DBAR1

A-AR5BAR1

B-AR1CAR5

A-AR1AR2D

A-AR1AR3D

A-AR1AR2AR5

A-AR1AR3AR5

A-DEAR1

A-DAR5AR1

A-AR5DAR1

B-AR1AR2D

B-AR1AR3D

B-AR1AR2AR5

B-AR1AR3AR5

B-DEAR1

B-DAR5AR1

B-AR5DAR1

AAR1B-D

AAR1B-AR5

ADB-AR1

AAR5B-AR1

BAR1C-D

BAR1C-AR5

AAR1AR2-D

AAR1AR3-D

AAR1AR2-AR5

AAR1AR3-AR5

ADE-AR1

ADAR5-AR1

AAR5D-AR1

BAR1AR2-D

BAR1AR3-D

BAR1AR2-AR5

BAR1AR3-AR5

BDE-AR1

BDAR5-AR1

BAR5D-AR1

In terms of high T1 energy, compounds having a structure in which the D ring, E ring or AR5 ring in the (X-b-1) structure is bonded to the A ring, B ring or C ring, or shares one ring with the A ring, B ring or C ring (X-a-1)) or shares one ring are preferred. In addition, compounds in which two sp2 carbon-sp2 carbon bonds connecting aryl or heteroaryl are at the o-position or the m-position have high T1 and are therefore preferred because they have a long life and high efficiency.

In addition, from the viewpoint of high TADF properties and high efficiency, it is preferable that X ^b in (Xb-1) is a divalent group represented by the formula (Xb-R5), in which the AR5 ring shares a ring with the A ring, the B ring or the C ring, and it is more preferable that the AR5 ring shares a ring with the B ring or the C ring.

＜Description of substituents in each ring＞

When the term "substituted or unsubstituted (substituted or unsubstituted)" is used in a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring for the A ring, B ring and C ring, the substituent may include a substituent formed by Formula (X-a-1), Formula (X-b-1) or Formula (X-a-1) and Formula (X-b-1). Other substituents may include one or more substituents selected from the substituent group Zα (excluding the substituents formed by Formula (X-a-1), Formula (X-b-1) or Formula (X-a-1) and Formula (X-b-1)). The other substituents are preferably phenyl, methyl, t-butyl or cyano. From the viewpoint of improving the charge transport function, among the A ring, B ring and C ring, it is preferable that the aryl ring or heteroaryl ring having a substituent formed by formula (X-a-1), formula (X-b-1) or formula (X-a-1) and formula (X-b-1) has one other substituent or is unsubstituted, and is more preferably unsubstituted. From the viewpoint of improving the charge transport function, it is more preferable that the ring having a substituent formed by formula (X-a-1), formula (X-b-1) or formula (X-a-1) and formula (X-b-1) does not have any other substituent.

When the term "substituted or unsubstituted (substituted or unsubstituted)" of a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring for a D ring, an E ring, an AR1 ring, an AR2 ring, an AR3 ring, an AR4 ring and an AR5 ring is used, the substituent may include one or more substituents selected from the substituent group Zα. The substituent is preferably phenyl, methyl, t-butyl or cyano. From the viewpoint of improving the charge transport function, it is preferable that each aromatic ring in the A ring, B ring, C ring, D ring, E ring, AR1 ring, AR2 ring, AR3 ring, AR4 ring or AR5 ring is unsubstituted or has one substituent, and it is more preferable that it is unsubstituted.

＜Desirable Part Structure＞

The polycyclic aromatic compound of the present invention preferably has a carbazole structure from the viewpoints of high carrier transport and good carrier balance, and a compound having a carbazole structure can be preferably used as a material for a hole transport layer, an electron blocking layer, and a host. In addition to a carbazole structure, a compound having a pyridine structure or a triadine structure is preferably used as a host material.

The compound of the present invention having pyridine or triadine can be preferably used as an electron transport host, a hole blocking layer, or an electron transport layer.

＜Polycyclic aromatic compound represented by formula (1a), formula (1b), or formula (1c)＞

The polycyclic aromatic compound represented by formula (1) is preferably a polycyclic aromatic compound represented by formula (1a), formula (1b) or formula (1c), and in this case, formula (X-a-1) is preferably represented by formula (X-a-2), and formula (X-b-1) is preferably represented by formula (X-b-2).

The partial structure represented by the formula (X-a-2) and the partial structure represented by the formula (X-b-2) are each bonded to Z (a ring constituent atom in Z, for example, a carbon atom) in the a ring, the b ring or the c ring in the formula (1a), the formula (1b) or the formula (1c) via a single bond, or the other side bonded to Z in the a ring, the b ring or the c ring is bonded to Z (a ring constituent atom in Z, for example, a carbon atom) in the partial structure, or shares a ring with the a ring, the b ring or the c ring, or shares a ring with the other partial structure bonded to the a ring, the b ring or the c ring, or shares one ring with the a ring, the b ring or the c ring, thereby forming a partial structure of a polycyclic aromatic compound represented by the formula (1a), the formula (1b) or the formula (1c).

Specifically, one or two selected from the group consisting of an Ar ¹ ring, an Ar ² ring, an Ar ³ ring and an Ar ⁴ ring in the formula (Xa-2) are bonded to Z in the a ring, the b ring or the c ring via a single bond, or are bonded to a d ring, an e ring or an AR5 ring in the partial structure represented by the formula (Xb-2) which is bonded to Z in the a ring, the b ring or the c ring, or share a ring with the a ring, the b ring or the c ring, or are bonded to the a ring, the b ring or the c ring, or share a ring with the d ring, the e ring or the AR5 ring in the formula (Xb-2) which shares any one of the rings with the a ring, the b ring or the c ring. In addition, one or two selected from the group consisting of a d ring, an e ring and an AR5 ring in the formula (Xb-2) are bonded to Z in the a ring, the b ring or the c ring via a single bond, or are bonded to Z in the a ring, the b ring or the c ring in the partial structure represented by the formula (Xa-2), or are bonded to Z in the Ar ¹ ring, the Ar ² ring, the Ar ³ ring or the Ar ⁴ ring, or are bonded to the a ring, the b ring or the c ring, or are bonded to the a ring, the b ring or the c ring, or are bonded to any one of the a ring, the b ring or the c ring, and are shared by the Ar ¹ ring, the Ar ² ring, the Ar ³ ring or the Ar ⁴ ring in the formula (Xa-2). For this structure, reference can be made to the explanation of how the partial structure represented by the above-described formula (Xa-1) and the partial structure represented by the formula (Xb-1) become the partial structure of the polycyclic aromatic compound represented by the formula (1).

In each of formulas (1b) and (1c), Y ¹ and Y ² are each independently >NR ^NY , >C(-R ^CY ) ₂ , >O, >Si(-R ^IY ) ₂ , >S or >Se. R ^NY , R ^CY and R ^IY are each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, and two R ^CY may be bonded to each other to form a ring, and two R ^IY may be bonded to each other to form a ring. When L is >NR ^NY , R ^NY is preferably a substituted or unsubstituted aryl, and more preferably phenyl which may be substituted with alkyl. When L is >C(-R ^CY ) ₂ , R ^CY is preferably methyl or phenyl. When L is >C(-R ^IY ) ₂ , R ^IY is preferably methyl or phenyl. Y ¹ and Y ² are each independently >NR ^NY , >C(-R ^CY ) ₂ , >O or >S, more preferably >O or >S. Y ¹ and Y ² may be the same or different, and are preferably the same.

In each of formulas (1a), (1b), (1c), (Xa-2), and (Xb-2), Z is a carbon atom having a bond with another ring, or -C(-R ^Z )= or -N=, and R ^Z is hydrogen or a substituent. However, two adjacent Zs constituting the e ring in formula (Xb-2) may be carbon atoms each bonded to two *s of formula (Xb-2-e). Either Z of the two adjacent Zs may be bonded to either *. In formula (Xb-2-e), X ^b is a divalent group represented by formula (Xb-R5), >O, >C(-R ^CX ) ₂ , >Si(-R ^IX ) ₂ , >S or >Se, and each R ^CX is independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, and two R ^CX may be bonded to each other to form a ring. R ^CX is preferably methyl or phenyl. R ^IX is each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, and two R ^IX may be bonded to each other to form a ring. R ^IX is preferably methyl or phenyl. Z in formula (Xb-2-e) is synonymous with Z constituting the d ring in formula (Xb-2), and is a carbon atom having a bond with another ring, or -C(-R ^Z )= or -N=.

In each of formulas (1a), (1b), (1c), (Xa-2), and (Xb-2), among Z, other than Z being a carbon atom having a bond with another ring, it is preferable that all are -C(-R ^Z )=, or one or two are -N=, and the others are -C(-R ^Z )=, and it is more preferable that all are -C(-R ^Z )=, or one is -N=, and the others are -C(-R ^Z )=. Among Z in each of formulas (1a), (1b), and (1c), it is most preferable that all are -C(-R ^Z )=, and it is most preferable that one of Z in each of formulas (Xa-2) and (Xb-2) is -N=, and the others are -C(-R ^Z )=. In each of formulas (1a), (1b), and (1c), when R ^Z is a substituent, examples of the substituent include a substituent formed in formula (Xa-2), formula (Xb-2), or formula (Xa-2) and formula (Xb-2). Examples of other substituents include one or more substituents selected from the substituent group Zα (excluding the substituents formed in formulas (Xa-2), formula (Xb-2), or formulas (Xa-2) and formula (Xb-2)). Examples of other substituents include phenyl, methyl, and cyano. In each of formulas (1a), (1b), and (1c), R ^Z is preferably hydrogen. Examples of the substituent when R ^Z is a substituent in each of formulas (Xa-2) and (Xb-2) include one or more substituents selected from the substituent group Zα. As a substituent, phenyl, methyl, t-butyl or cyano is preferable. In each of formulas (Xa-2) and (Xb-2), R ^Z is preferably hydrogen.

In equation (Xa-2), X ^a is identical to X ^a in equation (Xa-1), and the desirable range is also the same.

For the Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring in formula (Xa-2), reference may be made to the description of the AR ¹ ring, AR ^{2 ring, AR 3 ring and AR 4 ring in formula (Xa-1), respectively. For example, any two selected from the group consisting of the Ar 1 ring, Ar 2} ring, Ar ³ ring and Ar ⁴ ring may be connected to each other by a single bond or a connecting group.

In formula (Xb-2), X ^b is synonymous with X ^b in formula (Xb-1). When X ^b is a divalent group represented by formula (XB-R5), the AR5 ring is preferably a 6-membered ring, for example, a benzene ring or a pyridine ring.

Preferred structural examples of formulas (1a), (1b), (1c), (X-a-2), and (X-a-1) are shown below. In addition, for formulas (1a), (1b), and (1c), the structures excluding each substructure represented by formulas (X-a-2) and (X-a-1) are shown.

(1a)

(1b)

(1c)

(X-a-2)

(X-b-2)

＜Replacement with heavy stable isotopes＞

Each element in the polycyclic aromatic compound represented by formula (1) includes multiple naturally occurring isotopes in the natural abundance ratio, unless otherwise specified. However, all or part of the elements in each structural formula may include a heavy stable isotope exceeding the natural abundance ratio (for example, 90 atom% or more in boron-11 ( ¹¹ B)). In this specification, this is simply referred to as "substituting" with a "heavy stable isotope." More specifically, one or more hydrogens can be replaced by deuterium, one or more nitrogens can be replaced by nitrogen-15 ( ¹⁵ N), one or more sulfurs can be replaced by sulfur-33 ( ³³ S), sulfur-34 ( ³⁴ S) or sulfur-36 ( ³⁶ S), one or more oxygens can be replaced by oxygen-17 ( ¹⁷ O) or oxygen-18 ( ¹⁸ O), one or more carbons can be replaced by carbon-13 ( ¹³ C), and one or more borons can be replaced by boron-11 ( ¹¹ B). The same applies to a structure represented by Formula (1a), Formula (1b) or Formula (1c), and this description also applies to a structure represented by Formula (1a), Formula (1b) or Formula (1c). By replacing at least some of the elements with heavy stable isotopes, particularly by replacing one or more borons with boron-11 ( ¹¹ B), the lifetime of an organic electroluminescent device using a polycyclic aromatic compound represented by formula (1) can be extended.

＜Substitution by deuterium＞

In the polycyclic aromatic compound represented by formula (1), all or part of the hydrogen may be deuterium. The same applies to the structure represented by formula (1a), formula (1b), or formula (1c), and the following description also applies to the polycyclic aromatic compound represented by formula (1a), formula (1b), or formula (1c).

For example, in the A ring, B ring and C ring, hydrogen in the aryl ring or heteroaryl ring and their substituents may be replaced with deuterium, and among these, a form in which all or part of the hydrogen in the aryl ring or heteroaryl ring is replaced with deuterium may be exemplified. In formula (X-b-1), all or part of the hydrogen in the aryl ring and heteroaryl ring in the D ring and E ring or the AR1 ring, AR2 ring, AR3 ring, AR4 ring or AR5 ring may be replaced with deuterium. Furthermore, from the viewpoint of durability, it is also preferable that all or part of the hydrogen in the polycyclic aromatic compound represented by formula (1) is deuterated.

＜Specific examples of polycyclic aromatic compounds of the present invention＞

Specific examples of the polycyclic aromatic compound of the present invention include compounds represented by any one of the structural formulae below, but the present invention is not limited thereto.

2. Method for producing polycyclic aromatic compounds

The polycyclic aromatic compound represented by formula (1) can be basically produced by first bonding an A ring (a ring), a B ring (b ring), and a C ring (c ring) having a halogen at any one position with O (first reaction), then bonding a condensed ring including an A ring (a ring), a B ring (b ring), and a C ring with boron to produce a partial structure (1) having a halogen (second reaction), and then connecting the partial structures (X-a-1) and (X-b-1) by a cross-coupling reaction (third reaction). In the first reaction, a general reaction such as a nucleophilic substitution reaction or a Ullmann reaction can be used, and in the second reaction, a tandem hetero Friedel-Crafts reaction (a sequential aromatic electrophilic substitution reaction, the same applies hereinafter) can be used. In the third reaction, a general reaction such as a Suzuki-Miyaura reaction, a Burchwald reaction, and a Goldberg reaction can be used. Additionally, it is also possible to obtain the final product by introducing B into a precursor that has previously connected partial structures (X-a-1) and partial structures (X-b-1) through the Bora-Friedel-Crafts reaction.

The second reaction is a reaction for introducing boron, which combines a condensed ring including an A ring (a ring), a B ring (b ring), and a C ring (c ring), as shown in the following scheme (1). First, the halogen atom between the nitrogen atoms is subjected to halogen-metal exchange with n-butyllithium, sec-butyllithium, or t-butyllithium. Next, boron trichloride or boron tribromide is added to perform metal exchange of lithium-boron, and then a Brønsted base such as N,N-diisopropylethylamine is added to cause a tandem Bora Friedel-Crafts reaction to obtain the target product. In the second reaction, a Lewis acid such as aluminum trichloride may be added to promote the reaction. In addition, the halogen atom Cl in the formula may be any of Cl, Br, and I, and may be appropriately selected in consideration of the reactivity of the substrate.

By appropriately selecting the raw materials to be used, a polycyclic aromatic compound having a substituent at a desired position can be synthesized.

Additionally, it can be synthesized using a general coupling reaction, such as the method described in Nature Photonics, 13, 540-546 (2019), Advanced Functional Materials, 2021,31, 2105805.

Specific examples of the solvent used in the above reaction include t-butylbenzene and xylene.

In addition, in the synthetic method of the above scheme (1), an example was shown in which a tandem hetero Friedel-Crafts reaction was induced by halogen-metal exchange between nitrogen atoms with butyllithium, etc. before adding boron trichloride or boron tribromide, etc.; however, the reaction can also proceed by adding boron trichloride or boron tribromide, etc. as a precursor in which the halogen becomes hydrogen.

In addition, as the orthometalation reagent used in the above scheme (1), examples thereof include alkyl lithiums such as methyl lithium, n-butyl lithium, sec-butyl lithium, and t-butyl lithium, and organic alkali metal compounds such as lithium diisopropylamide, lithium tetramethylpiperidide, lithium hexamethyldisilazide, and potassium hexamethyldisilazide.

In addition, as the metal-boron metal exchange reagent used in the above scheme (1), boron halides such as boron trifluoride, boron trichloride, boron tribromide, and boron triiodide, boron alkoxides, and boron aryloxyoxides can be mentioned.

In addition, the Bronsted bases used in the above scheme (1) include N,N-diisopropylethylamine, triethylamine, 2,2,6,6-tetramethylpiperidine, 1,2,2,6,6-pentamethylpiperidine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2,6-lutidine, sodium tetraphenylborate, potassium tetraphenylborate, triphenylborane, tetraphenylsilane, Ar ₄ BNa, Examples include Ar ₄ BK, Ar ₃ B, Ar ₄ Si (wherein Ar is aryl such as phenyl).

The Lewis acids used in the above scheme (1) include AlCl ₃ , AlBr ₃ , AlF ₃ , BF ₃ OEt ₂ , BCl ₃ , BBr ₃ , BI ₃ , GaCl ₃ , GaBr ₃ , InCl ₃ , InBr ₃ , In(OTf) ₃ , SnCl ₄ , SnBr ₄ , AgOTf, ScCl ₃ , Sc(OTf) ₃ , ZnCl ₂ , ZnBr ₂ , Zn(OTf) ₂ , MgCl ₂ , MgBr ₂ , Mg(OTf) ₂ , LiOTf, NaOTf, KOTf, Me ₃ SiOTf, Cu(OTf) ₂ , CuCl ₂ , YCl ₃ , Y(OTf) ₃ , TiCl ₄ , TiBr ₄ , ZrCl ₄ , Examples include ZrBr ₄ , FeCl ₃ , FeBr ₃ , CoCl ₃ , and CoBr ₃ .

In the above scheme (1), a Bronsted base or a Lewis acid may be used to promote the tandem hetero Friedel-Crafts reaction. However, in the case where a boron halide such as boron trifluoride, boron trichloride, boron tribromide, or boron triiodide is used, acids such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, or hydrogen iodide are generated as the aromatic electrophilic substitution reaction progresses, so the use of a Bronsted base that captures the acid is effective. On the other hand, in the case where an aminated halide of boron or an alkoxy of boron is used, amines and alcohols are generated as the aromatic electrophilic substitution reaction progresses, so in many cases it is not necessary to use a Bronsted base, but since the elimination ability of amino or alkoxy is low, the use of a Lewis acid that promotes the elimination is effective.

In addition, the polycyclic aromatic compounds of the present invention include those in which at least some hydrogen atoms are substituted with deuterium or with halogens such as fluorine or chlorine, and such compounds and the like can be synthesized in the same manner as described above by using a raw material in which a desired portion is deuterated, fluorinated or chlorinated.

3. Organic electroluminescent devices

The polycyclic aromatic compound according to the present invention can be used as a material for an organic device. Examples of the organic device include an organic electroluminescent device, an organic field effect transistor, or an organic thin film solar cell. The polycyclic aromatic compound according to the present invention can be used particularly as an organic electroluminescent device.

3-1. Structure of organic electroluminescent device

Hereinafter, an organic EL device according to the present embodiment will be described in detail based on the drawings. Fig. 1 is a schematic cross-sectional view showing an organic EL device according to the present embodiment.

＜Structure of organic electroluminescent device＞

The organic EL device (100) illustrated in FIG. 1 has a substrate (101), an anode (102) provided on the substrate (101), a hole injection layer (103) provided on the anode (102), a hole transport layer (104) provided on the hole injection layer (103), an emitting layer (105) provided on the hole transport layer (104), an electron transport layer (106) provided on the emitting layer (105), an electron injection layer (107) provided on the electron transport layer (106), and a cathode (108) provided on the electron injection layer (107).

In addition, the organic EL element (100) may be configured by reversing the manufacturing order, for example, to have a substrate (101), a cathode (108) provided on the substrate (101), an electron injection layer (107) provided on the cathode (108), an electron transport layer (106) provided on the electron injection layer (107), an emitting layer (105) provided on the electron transport layer (106), a hole transport layer (104) provided on the emitting layer (105), a hole injection layer (103) provided on the hole transport layer (104), and an anode (102) provided on the hole injection layer (103).

It is not necessary to have all of the above layers, and the minimum configuration unit is a configuration consisting of an anode (102), a light-emitting layer (105), and a cathode (108), and the hole injection layer (103), the hole transport layer (104), the electron transport layer (106), and the electron injection layer (107) are layers that are provided arbitrarily. In addition, each of the above layers may be composed of a single layer or may be composed of multiple layers.

In the form of the layer constituting the organic EL device, in addition to the above-described "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron transport layer/electron injection layer/cathode" configuration, there are also "substrate/anode/hole transport layer/light-emitting layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron transport layer/cathode", "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron injection layer/cathode", "substrate/anode/hole injection layer/hole transport layer/light-emitting layer/electron transport layer/cathode", "substrate/anode/light-emitting layer/electron transport layer/cathode", "substrate/anode/hole transport layer/light-emitting layer/electron injection layer/cathode", It may also have the configuration of "substrate/anode/hole injection layer/light-emitting layer/electron injection layer/cathode", "substrate/anode/hole injection layer/light-emitting layer/electron transport layer/cathode", "substrate/anode/light-emitting layer/electron transport layer/cathode", "substrate/anode/light-emitting layer/electron injection layer/cathode".

The organic EL device may further have one or both of an electron-blocking layer (electron-blocking layer) and a hole-blocking layer (hole-blocking layer). The electron-blocking layer has a LUMO shallower than that of the emitting layer and a HOMO close to that of the emitting layer or the hole-transporting layer, and is disposed between the emitting layer and the hole-transporting layer. Since electrons remain in the emitting layer and do not leak to the hole-transporting layer, short lifetime due to deterioration of the hole-transporting layer and decreased efficiency due to decreased recombination efficiency can be prevented. The hole-blocking layer has a HOMO deeper than that of the emitting layer and a LUMO close to that of the emitting layer or the hole-transporting layer, and is disposed between the emitting layer and the electron-transporting layer. Since holes remain in the emitting layer and do not leak to the electron-transporting layer, short lifetime due to deterioration of the electron-transporting layer and decreased efficiency due to decreased recombination efficiency can be prevented. The hole injection/transporting layer may also serve as the electron-blocking layer. The electron injection/transporting layer may also serve as the hole-blocking layer.

The organic EL device may have a higher T1 layer. The high T1 layer has a higher T1 than the host compound, assisting dopant compound, or emitting dopant compound used in the emitting layer, and is disposed between the emitting layer and the hole transport layer and/or between the emitting layer and the electron blocking layer. The T1 energy value varies depending on the light-emitting mechanism of the device, but has a higher T1 than the compound used in the host. By having the high T1 layer around the emitting layer, triplet energy is trapped, and triplet energy, which normally does not lead to light emission in fluorescent molecules, is converted into singlet energy, thereby achieving high efficiency. The hole injection/transport layer or the electron blocking layer may also serve as the high T1 layer. The electron injection/transport layer or the hole blocking layer may also serve as the high T1 layer.

The polycyclic aromatic compound of the present invention is preferably used as an organic electroluminescent device material. In general, a compound having a donor structure can be used as a hole-transporting host material and a hole transport layer of an emitting layer, a compound having an acceptor structure can be used as an electron-transporting host material and an electron transport layer, and a compound having both a donor structure and an acceptor structure can be used as both a hole transport layer, a host and an electron transport layer of an emitting layer. For the donor structure and the acceptor structure, see, for example, Advanced Functional Materials 2020, 2008332. More specifically, the donor structure may include a triarylamine structure and a carbazole structure, and the acceptor structure may include a triazine structure, a pyrimidine structure, and a pyridine structure. The polycyclic aromatic compound according to the present invention can be used as a host material of an emitting layer, a hole transport layer material, an electron transport layer material, etc., depending on the partial structure it has.

3-2. Substrate of organic electroluminescent device

The substrate (101) is a support for the organic EL element (100), and is typically made of quartz, glass, metal, plastic, or the like. The substrate (101) is formed in a plate shape, film shape, or sheet shape depending on the purpose, and for example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, or the like is used. Among these, a glass plate and a plate made of transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, or polysulfone are preferable. If it is a glass substrate, soda-lime glass or alkali-free glass can be used, and furthermore, the thickness can be sufficient to maintain mechanical strength. In addition, on the substrate (101), a gas barrier film such as a dense silicon oxide film may be provided on at least one surface in order to increase the gas barrier property, and particularly, when a plate, film, or sheet made of synthetic resin with low gas barrier property is used as the substrate (101), it is preferable to provide a gas barrier film.

3-3. Anode of organic electroluminescent device

The anode (102) plays a role in injecting holes into the light-emitting layer (105). In addition, when at least one of a hole injection layer (103) and a hole transport layer (104) is installed between the anode (102) and the light-emitting layer (105), holes are injected into the light-emitting layer (105) through these layers.

Examples of materials forming the anode (102) include inorganic compounds and organic compounds. Examples of inorganic compounds include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), indium-zinc oxide (IZO), etc.), halogenated metals (copper iodide, etc.), copper sulfide, carbon black, ITO glass, Nesa glass, etc. Examples of organic compounds include polythiophenes such as poly(3-methylthiophene), conductive polymers such as polypyrrole, and polyaniline, etc. In addition, materials used as anodes of organic EL devices can be appropriately selected and used.

3-4. Hole injection layer and hole transport layer of organic electroluminescent device

The hole injection layer (103) plays a role of efficiently injecting holes moving from the anode (102) into the light-emitting layer (105) or the hole transport layer (104). The hole transport layer (104) plays a role of efficiently transporting holes injected from the anode (102) or holes injected from the anode (102) through the hole injection layer (103) to the light-emitting layer (105). The hole injection layer (103) and the hole transport layer (104) are each formed by laminating or mixing one or two or more types of hole injection/transport materials. In addition, an inorganic salt such as iron (III) chloride may be added to the hole injection/transport material to form a layer.

As a hole injection/transport material, it is necessary to efficiently inject and transport holes from the anode between electrodes given an electric field, and it is desirable to have high hole injection efficiency and to efficiently transport the injected holes. To this end, it is desirable to have a small ionization potential, a large hole mobility, excellent stability, and a material that is unlikely to generate trapping impurities during production and use. It is also desirable to use the polycyclic aromatic compound of the present invention as a material for a hole transport layer.

As a material forming the hole injection layer (103) and the hole transport layer (104), any compound can be selected and used from among compounds conventionally used as charge transport materials for holes in photoconductive materials, known compounds used in hole injection layers and hole transport layers of p-type semiconductors, and organic EL devices. Specific examples of these include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis(N-arylcarbazole) or bis(N-alkylcarbazole), triarylamine derivatives (polymers having an aromatic tertiary amino in the main chain or side chain, 1,1-bis(4-di-p-triylaminophenyl)cyclohexane, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine, N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine, N ⁴ ,N ^4' -Diphenyl- ^{N 4} ,N ^4' -Bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-biphenyl]-4,4'-diamine, N ⁴ ,N ⁴ ,N ^4' ,N ^4' -Tetra[1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-4,4'-diamine, 4,4',4" -Tris(3-methylphenyl(phenyl)amino)triphenylamine, etc. triphenylamine derivatives, starburstamine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives or thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (for example, Examples thereof include heterocyclic compounds such as 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile, porphyrin derivatives, polysilane, etc. In the polymer system, polycarbonate or styrene derivatives having the above monomer in the side chain, polyvinylcarbazole, and polysilane are preferable, but any compound that can form a thin film necessary for producing a light-emitting element, inject holes from the anode, and transport holes is not particularly limited.

In addition, it is known that the conductivity of organic semiconductors is strongly affected by their doping. These organic semiconductor matrix materials are composed of compounds having good electron donating properties or compounds having good electron accepting properties. For doping of electron donating substances, strong electron acceptors such as tetracyanoquinone dimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinone dimethane (F4TCNQ) are known (see, for example, the literature "M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204(1998)" and the literature "J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731(1998)"). These generate so-called holes by an electron transfer process in an electron-donating base material (hole transport material). The conductivity of the base material changes considerably depending on the number and mobility of holes. As matrix materials having hole transport properties, for example, benzidine derivatives (such as TPD) or starburstamine derivatives (such as TDATA) or specific metal phthalocyanines (particularly, zinc phthalocyanine (ZnPc)) are known (Japanese Patent Application Laid-Open No. 2005-167175).

The above-described hole injection layer material and hole transport layer material can also be used as a hole layer material, as a polymer compound in which a reactive compound having a reactive substituent substituted therein is polymerized as a monomer, or a polymer crosslinked product thereof, or a pendant polymer compound in which a main chain polymer and the reactive compound are reacted, or a pendant polymer crosslinked product thereof.

3-5. Light-emitting layer of organic electroluminescent device

The light-emitting layer (105) is a layer that emits light by recombining holes injected from the anode (102) and electrons injected from the cathode (108) between electrodes to which an electric field is applied. The material forming the light-emitting layer (105) may be a compound (light-emitting compound) that is excited by the recombination of holes and electrons and emits light. It is preferable that the compound be a compound that can form a stable thin film shape and exhibits strong light-emitting (fluorescent) efficiency in a solid state. The polycyclic aromatic compound of the present invention is also preferably used as a material for the light-emitting layer.

The light-emitting layer may be composed of a single layer or multiple layers, and each is formed by light-emitting layer materials (host material, dopant material). The host material and the dopant material may be one type, or a combination of two or more types. The dopant material may be included in the entirety of the host material, or may be included partially. As a doping method, the dopant material may be formed by a co-deposition method with the host material, but may also be mixed in advance with the host material and then simultaneously deposited, or may be mixed in advance with the host material and then mixed by a wet film formation method.

The amount of the host material to be used varies depending on the type of the host material, and can be determined based on the characteristics of the host material. The standard for the amount of the host material to be used is preferably 50 to 99.999 mass%, more preferably 80 to 99.95 mass%, and even more preferably 90 to 99.9 mass%, based on the total mass of the material for the light-emitting layer.

The amount of dopant material to be used varies depending on the type of dopant material, and can be determined based on the characteristics of the dopant material. The standard for the amount of dopant material to be used is preferably 0.001 to 50 mass%, more preferably 0.05 to 20 mass%, and even more preferably 0.1 to 10 mass%, based on the total mass of the material for the light-emitting layer. The above range is preferable in that, for example, the concentration quenching phenomenon can be prevented. In addition, from the viewpoint of durability, it is also preferable that some or all of the hydrogen in the dopant material is deuterated.

As the dopant material, an emitting dopant material and an assisting dopant material may be used. It is preferable to use a thermally activated delayed fluorescence material as the assisting dopant material. In an organic electroluminescent device using the assisting dopant material, it is preferable that the amount of the emitting dopant material used is low in that the concentration quenching phenomenon can be prevented. It is preferable that the amount of the assisting dopant material used is high in terms of the efficiency of the thermally activated delayed fluorescence mechanism. Furthermore, in an organic electroluminescent device using a thermally activated delayed fluorescence assisting dopant material, it is preferable that the amount of the emitting dopant material used is low compared to the amount of the assisting dopant material used in terms of the efficiency of the thermally activated delayed fluorescence mechanism of the assisting dopant material.

In the case where an assisting dopant material is used, the standards for the usage amounts of the host material, the assisting dopant material and the emitting dopant material are 40 to 99 mass%, 59 to 1 mass% and 20 to 0.001 mass%, respectively, based on the total mass of the material for the light-emitting layer, preferably 60 to 95 mass%, 39 to 5 mass% and 10 to 0.01 mass%, respectively, and more preferably 70 to 90 mass%, 29 to 10 mass% and 5 to 0.05 mass%.

＜Host Material＞

Host materials include condensed ring derivatives such as anthracene or pyrene, which have been previously known as luminescent materials; bistyryl derivatives such as bisstyrylanthracene derivatives or distyrylbenzene derivatives; tetraphenylbutadiene derivatives; cyclopentadiene derivatives; fluorene derivatives; benzofluorene derivatives; N-phenylcarbazole derivatives; and carbazonitrile derivatives.

From the viewpoint of promoting rather than inhibiting the generation of TADF in the light-emitting layer, the triplet energy of the host material is preferably higher than the triplet energy of the dopant or assisting dopant having the highest triplet energy in the light-emitting layer, and specifically, the triplet energy of the host material is preferably 0.01 eV or higher, more preferably 0.03 eV or higher, and still more preferably 0.1 eV or higher. In addition, a TADF active compound may be used in the host material.

The host material may be a single type or a combination of multiple types. In the case of a combination of multiple types, it is preferable that it be a combination of a hole-transporting host material and an electron-transporting host material.

The polycyclic aromatic compound of the present invention can be preferably used as a host material. The polycyclic aromatic compound of the present invention may be used alone, as a hole-transporting host material, or as an electron-transporting host material. The polycyclic aromatic compound of the present invention is particularly preferably used as an electron-transporting host material.

[Hole-transporting host material (HH) and electron-transporting host material (EH)]

The hole-transporting host material (HH) and the electron-transporting host material (EH) satisfy the following relationships for the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO).

The HOMO of the hole-transporting host material (HH) is shallower than the HOMO of the electron-transporting host material (EH), and also the LUMO of the electron-transporting host material (EH) is deeper than the LUMO of the hole-transporting host material (HH).

Additionally, it is preferable that the HOMO of the emitting dopant is shallower than the HOMO of the hole-transporting host material (HH), or that the LUMO of the emitting dopant is deeper than the LUMO of the electron-transporting host material (EH).

In addition, from the viewpoint of promoting rather than inhibiting the generation of TADF in the emitting layer, the lowest excited triplet energy level (E _T1 ) of the hole-transporting host material (HH) and the electron-transporting host material (EH) is preferably higher than the E _T1 of the emitting dopant or the assisting dopant having the highest E _T1 in the emitting layer, and specifically, the E _T1 of the host material is preferably 0.01 eV or higher, more preferably 0.03 eV or higher, and even more preferably 0.1 eV or higher than the E _T1 of the emitting dopant or the assisting dopant. In addition, the E _T1 of the host material is preferably 2.47 eV or higher, more preferably 2.49 eV or higher, and even more preferably 2.56 eV or higher.

In addition, it is also preferable to use a hole-transporting host material in the hole-transporting layer adjacent to the light-emitting layer, and to use an electron-transporting host material in the electron-transporting layer adjacent to this light-emitting layer. This is because it becomes difficult for carrier leakage and energy leakage to occur from the light-emitting layer to the adjacent layer, and thus a highly efficient organic EL device can be obtained. The host material (hole-transporting host material) in the light-emitting layer and the material of the hole-transporting layer may be the same or different. In addition, the host material (electron-transporting host material) in the light-emitting layer and the material of the electron-transporting layer may be the same or different.

Hereinafter, hole-transporting host materials and electron-transporting host materials that can be used together with the polycyclic aromatic compound of the present invention are exemplified.

[Hole transport host material (HH)]

Examples of preferred hole-transporting host materials (HH) include compounds represented by formula (HH-1), or having a partial structure represented by formula (HH-1) and a structure including three or more rings selected from the group consisting of aryl rings and heteroaryl rings. It is preferred that the compound does not include any of an imine structure (-N=C-; including a partial structure of a heteroaryl ring), boron (>B-), and cyano (CN).

In equation (HH-1),

Q is ＞O, ＞S or ＞NA ^H ,

In formula (HH-1), one carbon atom next to the carbon atom to which Q is bonded in each of the two phenyls may be bonded to each other as L,

L is a single bond, ＞O, ＞S or ＞C(-A ^H ) ₂ ,

A ^H is Hydrogen, aryl or heteroaryl, and the two A ^H in ＞C(-A ^H ) ₂ may be bonded to each other.

When the hole-transport host material includes a structure represented by formula (HH-1) as a partial structure, it may include one such partial structure, but it is also preferable to include two or more of them. When it includes two or more, the two or more partial structures may be the same or different. The two or more partial structures may be bonded to each other by a single bond, may be bonded so as to share any ring included in the partial structure, or may be bonded so as to condense any ring included in the partial structure. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

The compound represented by the above formula (HH-1) or having a partial structure represented by the formula (HH-1) has a structure including three or more rings selected from the group consisting of an aryl ring and a heteroaryl ring. The number of rings included is preferably 6 or more, more preferably 8 or more. In addition, it is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. The number of rings means the number as a monocyclic ring, and for a condensed ring, it is the number counting the monocyclic rings constituting the condensed ring.

The hole-transporting host material is preferably a compound including at least one partial structure selected from the group consisting of a triarylamine structure, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a condensed polycyclic ring including phenoxazine or phenothiazine. The hole-transporting host material may include one such partial structure, but it is also preferable to include two or more of them. When it includes two or more, the two or more partial structures may be the same or different from each other.

Specific examples of the positive-spot transport host material include the following compounds.

Among the above, HH-1-1, HH-1-2, HH-1-4~HH-1-12, HH-1-17, HH-1-18, HH-1-20~HH-1-24, HH-1-82, HH-1-84~HH-1-89, HH-1-91, HH-1-92, HH-1-106~HH-1-108 and HH-1-109~HH-1-115 are preferable.

[Electron Transport Host Material (EH)]

Examples of electron-transporting host materials (EH) include compounds having a structure represented by formulae (EH-1A) to (EH-1D), or having a partial structure represented by formulae (EH-1A) to (EH-1D) and including three or more rings selected from the group consisting of aryl rings and heteroaryl rings.

In the case of (EH-1A)~(EH-1D),

Ar is a heteroaryl ring containing N=C as a ring-forming substructure,

Z is a single bond, -O-, -S- or -N(-A ^E )-,

The carbon atom next to the carbon atom to which Z is bonded and the A ^E to which Z is bonded may be bonded to each other as L,

L is a single bond, ＞O, ＞S or ＞C(-A ^E ) ₂ ,

A ^E is aryl, heteroaryl or triarylsilyl, and in formula (EH-1C), any one of A ^E may be diarylamino,

Two A ^E 's bonded to the same atom may be bonded to each other through L,

X is C, P or S,

When X is C, n=2, m=1,

When X is P, n=3, m=1,

When X is S, n=2, m=1~2.

The compound represented by the above formulas (EH-1A) to (EH-1D), or having a partial structure represented by the formulas (EH-1A) to (EH-1D), has a structure including three or more rings selected from the group consisting of an aryl ring and a heteroaryl ring. The number of rings included is preferably 4 or more, more preferably 6 or more, and still more preferably 8 or more. In addition, it is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less. The number of rings means the number as a monocyclic ring, and for a condensed ring, it is the number counting the monocyclic rings constituting the condensed ring.

When the electron-transport host material includes a structure represented by formulas (EH-1A) to (EH-1D) as a partial structure, it may include one such partial structure, but it is also preferable to include two or more of them. When including two or more, the two or more partial structures may be the same or different. The two or more partial structures may be bonded to each other by a single bond, may be bonded by sharing any ring included in the partial structure, or may be bonded by condensing any ring included in the partial structure. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

Specific examples of electron-transporting host materials include the following compounds.

As another preferred example of the electron-transporting host material (a compound having a partial structure represented by the formula (EH-1)), a polycyclic aromatic compound represented by the following formula (EH-1b) or a multimer of a polycyclic aromatic compound having multiple structures represented by the following formula (EH-1b) can be mentioned.

In the formula (EH-1b),

R ¹ , R ² , R ³ , R ⁴ and R ⁵ (hereinafter also referred to as “R ¹ etc.”) are each independently hydrogen or a substituent. The substituent may be a substituent selected from the substituent group Z.

In formula (EH-1b), X ¹ and X ² are each independently ＞NR (amine nitrogen), ＞O, ＞C(-R) ₂ , ＞S or ＞Se, and X ¹ and X ² are Not all of them are ＞C(-R) ₂ ,

In the above >NR and >C(-R) _2, each R is independently hydrogen or a substituent selected from the substituent group Z, and may be substituted with aryl, heteroaryl, alkyl or cycloalkyl (above, the second substituent), and each R in the above >NR and >C(-R) ₂ may be independently bonded to one or more rings of the a ring, b ring and c ring via a linking group or a single bond.

Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ⁶ (hereinafter also referred to as "Y ¹ etc.") are each independently =C(-R)- or =N-(pyridinic nitrogen), and at least one is =N-(pyridinic nitrogen),

In the above =C(-R)-, each R is independently hydrogen or a substituent selected from the substituent group Z.

The adjacent groups among R in =C(-R)- as the above R ¹ , R ² , R ³ , R ⁴ and R ⁵ , and Y ¹ to Y ⁶ may be bonded to form an aryl ring or a heteroaryl ring together with one or more rings among the A ring, the B ring and the C ring, and at least one hydrogen in the formed ring may be substituted with aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, diarylboryl (two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy or aryloxy (above, a first substituent), and at least one hydrogen among these may be further substituted with aryl, heteroaryl, alkyl or cycloalkyl (above, a second substituent).

In the compounds and structures represented by the formula (EH-1b), one or more hydrogen atoms may be replaced by cyano, halogen, or deuterium.

In formula (EH-1b), it is preferred that R ¹ , R ² , R ³ , R ⁴ and R ⁵ are all hydrogen, or that R ³ and R ⁴ are both hydrogen, and further that at least one selected from the group consisting of R ¹ , R ² and R ⁵ is a substituent other than hydrogen, and the others are hydrogen. As the substituent, aryl which may be substituted with alkyl, alkyl or heteroaryl, heteroaryl which may be substituted with alkyl or aryl, or diarylamino which may be substituted with alkyl or aryl is preferred. At this time, alkyl having 1 to 6 carbon atoms (methyl, t-butyl, etc.) is preferable, aryl having phenyl or biphenyl is preferable, and heteroaryl having triazinyl, carbazolyl (2-carbazolyl, 3-carbazolyl, 9-carbazolyl, etc.), pyrimidinyl, pyridinyl, dibenzofuranyl, or dibenzothienyl is preferable. Specific examples include phenyl, biphenyl, diphenyltriazinyl, carbazolyltriazinyl, monophenylpyrimidinyl, diphenylpyrimidinyl, carbazolyltriazinyl, pyridinyl, dibenzofuranyl, and dibenzothienyl.

Y ¹ etc. are each independently =C(-R)- or =N-, and at least one is =N-. Any of Y ¹ to Y ⁶ may be =N-. Preferably, Y ¹ and Y ⁶ are =N-(a ring is a pyrimidine ring), Y ¹ or Y ⁶ are =N-(a ring is a pyridine ring), Y ² and Y ⁵ are =N-(b ring and c ring are a pyridine ring), Y ³ and Y ⁴ are =N-(b ring and c ring are a pyridine ring), Y ² to Y ⁵ are =N-(b ring and c ring are a pyrimidine ring), Y ¹ , Y ³ , Y ⁴ and Y ⁶ are =N-(a ring is a pyrimidine ring, b ring and c ring are a pyridine ring), Y ¹ , Y ² , Y ⁵ and Y ⁶ are =N-(a ring is a pyrimidine ring, b ring and c ring are a pyridine ring), Y ¹ to Y ⁶ are =N-(a ring, b ring and c ring are a pyrimidine ring), Y ² or Y ⁵ are =N-(b ring or c ring is It is a pyridine ring.

In addition, in addition to the above arrangement relationship of =N-, it is preferable that X ¹ and X ² are >O, and a polycyclic aromatic compound including a partial structure represented by one of the following formulas is preferable.

In particular, polycyclic aromatic compounds containing a partial structure represented by the formula (EH-1b-N1) have higher E _S1 , higher E _T1 , compared to structures without N. It has a small △E _S1T1 .

Specific examples of polycyclic aromatic compounds represented by the formula (EH-1b) are shown below.

Among the above, EH-1-1 to EH-1-4, EH-1-10, EH-1-21 to EH-1-25, EH-1-32, EH-1-33, EH-1-51 ~EH-1-59, EH-1-61, EH-1-66, EH-1-68, EH-1-71, EH-1-72, EH-1-90, EH-1-94~EH-1-99, EH-1-100, EH-1-101, EH-1-104, EH-1-115, EH-1-117, EH- 1-120, EH-1-122, EH-1-123, EH-1-127 to EH-1-130 are preferred.

[Combination of hole-transporting host materials and electron-transporting host materials]

The combination of the hole-transporting host material and the electron-transporting host material is selected by the HOMO, LUMO and lowest excited triplet energy level (E _T1 ) of the hole-transporting host material, the electron-transporting host material and the dopant material.

For HOMO and LUMO, a combination is selected in which the HOMO (HH) of the hole-transporting host material is shallower than the HOMO (EH) of the electron-transporting host material, and the LUMO (EH) of the electron-transporting host material is deeper than the LUMO (HH) of the hole-transporting host material, and more specifically, a combination in which the HOMO (HH) is shallower than the HOMO (EH) by 0.10 eV or more and the LUMO (HH) is deeper than the HOMO (EH) by 0.10 eV or more is preferable, a combination in which the HOMO (HH) is shallower than the HOMO (EH) by 0.20 eV or more and the LUMO (HH) is deeper than the HOMO (EH) by 0.20 eV or more is more preferable, and a combination in which the HOMO (HH) is shallower than the HOMO (EH) by 0.25 eV or more and the LUMO (HH) is deeper than the HOMO (EH) by 0.25 eV or more. Deeper combinations of 0.25 eV or more are more desirable.

The hole-transport host material and the electron-transport host material may be a combination that forms an assembly called an exciplex. It is generally known that an exciplex is easily formed between a material having a relatively deep LUMO level and a material having a shallow HOMO level. The interaction of the hole-transport host material and the electron-transport host material, specifically whether or not an exciplex is formed, can be judged by forming a monolayer film composed of only the hole-transport host material and the electron-transport host material under the same conditions for forming a light-emitting layer, measuring an emission spectrum (fluorescence, phosphorescence spectrum), and comparing the obtained emission spectrum with an emission spectrum displayed by each of the hole-transport host material and the electron-transport host material alone. The spectrum of the mixed film including the hole-transport host material and the electron-transport host material can be judged by exhibiting an emission wavelength that is different from either the film spectrum of the hole-transport host material or the film spectrum of the electron-transport host material. Specifically, it is sufficient that the peak wavelengths of the spectra differ by 10 nm or more as an indicator.

Specific examples of combinations of a hole-transporting host material and an electron-transporting host material that do not form an exciplex include the following combinations. In order to satisfy the physical properties of the above HOMO, LUMO and E _T1 , in the hole-transporting host material, compounds having carbazole, dibenzofuran, dibenzothiophene, triarylamine, indolocarbazole and benzoxazinophenoxazine as partial structures are preferable, compounds having carbazole, dibenzofuran and dibenzothiophene as partial structures are more preferable, and compounds having carbazole as partial structures are even more preferable. Likewise, for the electron-transporting host material, compounds having pyridine, triazine, phosphine oxide, benzoflopyridine and dibenzoxacillin as partial structures are preferable, compounds having triazine, phosphine oxide, benzoflopyridine and dibenzoxacillin as partial structures are more preferable, and compounds having triazine are still more preferable.

More specifically, the hole transport host material is preferably selected from the group consisting of HH-1-1, HH-1-2, HH-1-4~HH-1-12, HH-1-17, HH-1-18, HH-1-20~HH-1-24, HH-1-82, HH-1-84~HH-1-89, HH-1-91, HH-1-92 and HH-1-106~HH-1-108, and the electron transport host material is preferably selected from the group consisting of EH-1-1~EH-1-4, EH-1-10, EH-1-21~EH-1-25, EH-1-32, EH-1-33, EH-1-51~EH-1-59, EH-1-61, EH-1-71, EH-1-72, It is preferable to select from the group consisting of EH-1-90, EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123 and EH-1-127 to EH-1-130. Preferred examples as a combination include compound HH-1-1 and compound EH-1-22, compound HH-1-1 and compound EH-1-23, compound HH-1-1 and compound EH-1-24, compound HH-1-2 and compound EH-1-22, compound HH-1-2 and compound EH-1-23, compound HH-1-2 and compound EH-1-24 or compound HH-1-1 and compound EH-1-128.

Specific examples of combinations of a hole-transporting host material and an electron-transporting host material forming an exciplex include the following combinations. In order to satisfy the physical properties of the above HOMO, LUMO and E _T1 , for the hole-transporting host material, compounds having carbazole, triarylamine, indolocarbazole and benzoxazinophenoxazine as partial structures are preferable, compounds having triarylamine, indolocarbazole and benzoxazinophenoxazine as partial structures are more preferable, and compounds having triarylamine as partial structures are even more preferable. Similarly, for the electron-transporting host material, compounds having pyridine, triazine, phosphine oxide and benzoflopyridine as partial structures are preferable, compounds having triazine, phosphine oxide, benzoflopyridine and dibenzoxacillin as partial structures are more preferable, and compounds having phosphine oxide and triazine are even more preferable.

More specifically, the hole transport host material is preferably selected from the group consisting of HH-1-1, HH-1-2, HH-1-11, HH-1-12, HH-1-17, HH-1-18, HH-1-23, HH-1-24 and HH-1-115, and the electron transport host material is preferably selected from the group consisting of EH-1-1 to EH-1-4, EH-1-21 to EH-1-25, EH-1-51 to EH-1-57, EH-1-59, EH-1-66, EH-1-68, EH-1-90, EH-1-94, EH-1-99, EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, It is preferred to be selected from the group consisting of EH-1-122, EH-1-123, and EH-1-127 to EH-1-130. Preferred examples as combinations include compound HH-1-1 and compound EH-1-21, compound HH-1-2 and compound EH-1-21, compound HH-1-12 and compound EH-1-94, compound HH-1-12 and compound EH-1-117, compound HH-1-1 and compound EH-1-130, compound HH-1-33 and compound EH-1-117, compound HH-1-48 and compound EH-1-117, compound HH-1-49 and compound EH-1-117, compound HH-1-115 and compound EH-1-99.

In addition, for the combination of specific hole-transporting host materials and electron-transporting host materials, see Organic Electronics 66(2019) 227-24, Advanced. Functional Materials 25(2015) 361-366., Advanced Materials 26(2014) 4730-4734., ACS Applied Materials and Interfaces 8(2016) 32984-32991., ACS Applied Materials and Interfaces 2016, 8, 9806-9810, ACS Applied Materials and Interfaces, 2016, 8, 32984-32991, Journal of Materials Chemistry C, 2018, 6, 8784-8792, Angewante Chemie International Edition. See also 2018, 57, 12380-12384, Advanced Functional Materials, 24, 2014, 3970, Advanced Materials, 26, 2014, 5684, Synthetic Metals, 201, 2015, 49, and Nature Photonics, 16, 212-218(2022).

＜Dopant material (emitting dopant material)＞

Any known compound can be used as a dopant material, and various materials can be selected depending on the desired emission color. Specifically, for example, condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene and chrysene, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bisstyryl derivatives such as bisstyrylanthracene derivatives or distyrylbenzene derivatives (Japanese Patent Application Laid-Open No. Hei 1-245087), bisstyrylarylene derivatives (Japanese Patent Application Laid-Open No. Hei 2-247278), diazindacene derivatives, furan derivatives, benzofuran derivatives, phenylisobenzofuran, Isobenzofuran derivatives such as dimethicylisobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran, and phenylisobenzofuran, dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzothiazolylcoumarin derivatives, 3-benzoimidazolylcoumarin derivatives, 3-benzoxazolylcoumarin derivatives, and coumarin derivatives such as dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzoanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazines Derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, perinone Examples thereof include derivatives, pyrrolopyrrole derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, deazaflavine derivatives, fluorene derivatives, and benzofluorene derivatives.

As an emitting dopant material, it is also preferable to use a polycyclic aromatic compound containing boron as described in paragraphs 0097 to 0269 of International Publication No. 2015/102118, International Publication No. 2020/162600, Japanese Patent Application Laid-Open No. 2021-077890, etc. The polycyclic aromatic compound having a boron atom may be a fluorescent substance or a TADF material (thermally activated delayed fluorescent substance). It is preferable that the polycyclic aromatic compound having a boron atom is a blue luminescent compound.

Preferred examples of polycyclic aromatic compounds containing boron include compounds represented by the following formula (12), formula (13), or formula (14).

A ring, B ring, C ring and D ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

Y is B (boron),

X ¹ , X ² , X ³ and X ⁴ are each independently >O, >NR, >S or >Se, and R of the >NR is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl or substituted or unsubstituted alkyl, and further, R of the >NR may be bonded to the A ring, B ring, C ring and/or D ring by a linking group or a single bond,

R ¹ and R ² are each independently hydrogen, alkyl having 1 to 6 carbon atoms, aryl having 6 to 12 carbon atoms, heteroaryl having 2 to 15 carbon atoms, or diarylamino (provided that aryl is aryl having 6 to 12 carbon atoms),

Z ¹ and Z ² are each independently any one substituent selected from the substituent group Z, Z ¹ may be bonded to the A ring as a linking group or a single bond, Z ² may be bonded to the C ring as a linking group or a single bond, and

In the compound represented by formula (12), one or more hydrogen atoms may be replaced with cyano, halogen, or deuterium.

When an aryl ring or heteroaryl ring is substituted in the A ring, B ring, C ring and D ring of formula (12), the substituent and Z ¹ and Z ² may be a substituent selected from the substituent group Z.

In formula (12), X ¹ , X ² , X ³ , and X ⁴ are each independently >O, >NR, >S, or >Se, and R of the >NR is each independently an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, a cycloalkyl having 3 to 12 carbon atoms, or an alkyl having 1 to 6 carbon atoms.

In the compound represented by formula (12), from the viewpoint of high TADF property, it is preferable that Z ¹ and Z ² are diphenylamino which may have a substituent or N-carbazolyl which may have a substituent, and it is more preferable that it is diphenylamino which may have a substituent. As the diphenylamino which may have a substituent, unsubstituted diphenylamino or diphenylamino having at least one alkyl having 1 to 4 carbon atoms is preferable, and unsubstituted diphenylamino or diphenylamino having at least one methyl at the m-position or o-position with respect to N is more preferable. From the viewpoints of ease of synthesis and emission wavelength, it is preferable that the aryl ring or heteroaryl ring in the A ring, B ring, C ring and D ring does not have a substituent other than Z ¹ and Z ² , or only has an alkyl having 1 to 6 carbon atoms as another substituent, and it is more preferable that it does not have a substituent other than Z ¹ and Z ² .

An example of a compound represented by Equation (12) is shown below.

Among equations (13) and (14),

A ¹¹ ring, A ²¹ ring, A ³¹ ring, B ¹¹ ring, B ²¹ ring, C ¹¹ ring and C ³¹ ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

Y ¹¹ , Y ²¹ , Y ³¹ are B (boron),

X ¹¹ , X ¹² , X ²¹ , X ²² , X ³¹ and X ³² are each independently >O, >NR, >S or >Se, and R of said >NR is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl or substituted or unsubstituted alkyl, and further, R of said >NR may be bonded to an A ¹¹ ring, an A ²¹ ring, an A 31 ring, a B ¹¹ ring, a B ²¹ ring, a C ¹¹ ring and/or a C ³¹ ring by a linking group or a ^single bond,

In the compounds represented by formulas (13) and (14), one or more hydrogen atoms may be replaced with cyano, halogen, or deuterium.

When an aryl ring or heteroaryl ring is substituted in the A ¹¹ ring, A ²¹ ring, A ³¹ ring, B ¹¹ ring, B ²¹ ring, C ¹¹ ring and C ³¹ ring of formulas (13) and (14), the substituent and Z ¹ and Z ² may be a substituent selected from the substituent group Z.

In formulas (13) and (14), X ¹¹ , X ¹² , X ²¹ , X ²² , X ³¹ , and X ³² are each independently >O, >NR, >S, or >Se, and R of the >NR is each independently an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, a cycloalkyl having 3 to 12 carbon atoms, or an alkyl having 1 to 6 carbon atoms.

Examples of compounds represented by formula (13) or formula (14) are shown below.

＜Assisting dopant (thermally activated delayed phosphor or phosphorescent material)＞

It is also preferred that the light-emitting layer contain an assisting dopant together with the emitting dopant and the host material. The assisting dopant is preferably a thermally activated delayed phosphor or phosphorescent material.

In this embodiment, it is also preferable to use a combination of a hole-transporting host material and an electron-transporting host material as a host, and the polycyclic aromatic compound of the present invention can be preferably used as the electron-transporting host material.

The lowest excited triplet energy level E(1, T, Sh) obtained from the shoulder on the short-wavelength side of the peak of the phosphorescence spectrum of the host compound is preferably higher than the lowest excited triplet energy levels E(2, T, Sh), E(3, T, Sh) of the emitting dopant or assisting dopant having the highest lowest excited triplet energy level in the emitting layer, from the viewpoint of promoting rather than inhibiting the generation of TADF in the emitting layer. Specifically, the lowest excited triplet energy level E(1, T, Sh) of the host compound is preferably 0.01 eV or higher than E(2, T, Sh), E(3, T, Sh), more preferably 0.03 eV or higher, and still more preferably 0.1 eV or higher.

[Thermo-activated delayed phosphor]

The term "thermally activated delayed fluorescence" refers to a compound that can absorb thermal energy to cause reverse inter-system crossing from the lowest excited triplet state to the lowest excited singlet state, thereby emitting delayed fluorescence by radiative deactivation from the lowest excited singlet state. However, the term "thermally activated delayed fluorescence" also includes a compound that passes through a higher-order triplet during the excitation process from the lowest excited triplet state to the lowest excited singlet state. For example, a paper by Monkman et al. of Durham University (NATURE COMMUNICATIONS, 7:13680, DOI: 10.1038/ncomms13680), a paper by Hosokai et al. of the National Institute of Advanced Industrial Science and Technology (Hosokai et al., Sci. Adv. 2017;3: e1603282), a paper by Sato et al. of Kyoto University (Scientific Reports, 7:4820, DOI: 10.1038/s41598-017-05007-7), a conference presentation by Sato et al. of Kyoto University (The 98th Spring Meeting of the Chemical Society of Japan, Presentation No.: 2I4-15, Mechanism of High-Efficiency Luminescence in Organic Electroluminescence Using DABNA as a Luminescent Molecule, Graduate School of Engineering, Kyoto University), a review by Bui et al. (DOI: 10.3762/bjoc.14.18), a review by Duan et al. Reviews (DOI:10.1063/1.5143501), reviews by Ding et al. (DOI:10.1088/1674-4926/42/5/050201), and reviews by Xie et al. (DOI:10.1002/adom.202002204) can be cited. In the present invention, when the fluorescence lifetime is measured at 300 K for a sample containing the target compound, it is determined that the target compound is a "thermally activated delayed fluorescent substance" if a slow fluorescence component is observed. Here, the slow fluorescence component means a fluorescence lifetime of 0.1 μsec or longer. The measurement of the fluorescence lifetime can be performed using, for example, a fluorescence lifetime measuring device (C11367-01, manufactured by Hamamatsu Photonics Co., Ltd.).

In a light-emitting layer further including a "thermally activated delayed phosphor" as an assisting dopant, it is preferable to use the above-described boron-containing polycyclic aromatic compound as an emitting dopant. That is, the "thermally activated delayed phosphor" can function as an assisting dopant that assists the light emission of the above-described boron-containing polycyclic aromatic compound.

In this specification, an organic electroluminescent device using a thermally activated delayed fluorescent substance as an assisting dopant is sometimes referred to as a “TAF device” (TADF Assisting Fluorescence device).

The term "host compound" in a TAF device means a compound having a lowest excited singlet energy level, as determined from a shoulder on the short-wavelength side of the peak of the fluorescence spectrum, higher than that of the thermally activated delayed fluorescent material and the emitting dopant as the assisting dopant.

The thermally activated delayed fluorophore (TADF compound) used in the TAF device is preferably a donor-acceptor type thermally activated delayed fluorophore (D-A type TADF compound) designed to localize the HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital) within the molecule by using an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor to enable efficient reverse intersystem crossing.

Here, the term “electron-donating substituent” (donor) in the present specification means a substituent and partial structure in which HOMO is localized among thermally activated delayed fluorescent molecules, and the term “electron-accepting substituent” (acceptor) means a substituent and partial structure in which LUMO is localized among thermally activated delayed fluorescent molecules.

In general, thermally activated delayed phosphors using a donor or an acceptor have a large spin-orbit coupling (SOC) due to their structure, a small exchange interaction between HOMO and LUMO, and a small △E _S1T1 , so that they can obtain a very fast inter-system crossing velocity. By using the polycyclic aromatic compound containing the above-mentioned boron as an emitting dopant and a thermally activated delayed phosphor (TADF material) as an assisting dopant, it is possible to provide a device that satisfies one or all of high efficiency, high color purity, and long life. The thermally activated delayed phosphor may be a compound whose emission spectrum at least partially overlaps with the absorption spectrum of the emitting dopant. The emitting dopant and the thermally activated delayed phosphor may both be included in the same layer, or may be included in adjacent layers or other nearby layers.

As a thermally activated delayed fluorescent material in a TAF device, for example, a compound in which a donor and an acceptor are bonded directly or through a spacer can be used. As an electron-donating group (donor structure) and an electron-accepting group (acceptor structure) used in the thermally activated delayed fluorescent material of the present invention, for example, a structure described in Chemistry of Materials, 2017, 29, 1946-1963 can be used. Donor structures include carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothienocarbazole, phenyldihydroindolocarbazole, phenylbicarbazole, bicarbazole, tercarbazole, diphenylcarbazolylamine, tetraphenylcarbazolyldiamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis(tert-butylphenyl)amine, N1-(4-(diphenylamino)phenyl)-N4,N4-diphenylbenzene-1,4-diamine, dimethyltetraphenyldihydroacridinediamine, tetramethyl-dihydro-indenoacridine, and diphenyl-dihydrodibenzoazacilline. The acceptor structures include sulfonyldibenzene, benzophenone, phenylenebis(phenylmethanone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, paraphthalonitrile, benzenetricarbonitrile, triazole, oxazole, thiaziazole, benzothiazole, benzobis(thiazole), benzoxazole, benzobis(oxazole), quinoline, benzimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide, dimethylanthracenone, anthracenedione, 5H-cyclopenta[1,2-b:5,4-b']dipyridine, fluorenedicarbonitrile, triphenyltriazine, pyrazinedicarbonitrile, pyrimidine, phenylpyrimidine, methylpyrimidine, Examples thereof include pyridinedicarbonitrile, dibenzoquinoxalinedicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthene dioxide, thiandrenetetraoxide, and tris(dimethylphenyl)borane. In particular, it is preferable that the compound having thermally activated delayed fluorescence in a TAF element is a compound having at least one selected from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenylsulfone, triazole, oxadiazole, thiadiazole, and benzophenone as a partial structure.

The compound used as an assisting dopant of the light-emitting layer in the TAF device is preferably a thermally activated delayed phosphor, and the emission spectrum of which at least partially overlaps with the absorption peak of the emitting dopant is a compound. Hereinafter, compounds that can be used as the second component (thermally activated delayed phosphor) of the light-emitting layer in the TAF device are exemplified. However, the compounds that can be used as the thermally activated delayed phosphor in the TAF device are not limited to the exemplified compounds below.

Additionally, a compound represented by any one of the following formulae (AD1), (AD2), and (AD3) can also be used as a thermally activated delayed fluorescent material.

In the above formulas (AD1), (AD2), and (AD3), M is each independently a single bond, -O-, >N-Ar or >CAr ₂ , and from the viewpoints of the depth of the HOMO of the formed partial structure and the height of the lowest excited singlet energy level and the lowest excited triplet energy level, it is preferably a single bond, -O- or >N-Ar. J is a spacer structure separating the donor partial structure and the acceptor partial structure, and is each independently an arylene having 6 to 18 carbon atoms, and from the viewpoint of the size of the conjugation exuding from the donor partial structure and the acceptor partial structure, an arylene having 6 to 12 carbon atoms is preferable. More specifically, phenylene, methylphenylene, and dimethylphenylene can be mentioned. Q is each independently =C(-H)- or =N-, and from the viewpoints of the shallowness of the LUMO of the formed partial structure and the height of the lowest excited singlet energy level and the lowest excited triplet energy level, it is preferably =N-. Ar is independently hydrogen, an aryl having 6 to 24 carbon atoms, a heteroaryl having 2 to 24 carbon atoms, an alkyl having 1 to 12 carbon atoms, or a cycloalkyl having 3 to 18 carbon atoms, and in view of the depth of HOMO of the partial structure formed and the height of the lowest excited singlet energy level and the lowest excited triplet energy level, is preferably hydrogen, an aryl having 6 to 12 carbon atoms, a heteroaryl having 2 to 14 carbon atoms, an alkyl having 1 to 4 carbon atoms, or a cycloalkyl having 6 to 10 carbon atoms, more preferably hydrogen, phenyl, tolyl, xylyl, mesityl, biphenyl, pyridyl, bipyridyl, triazinyl, carbazolyl, dimethylcarbazolyl, di-tert-butylcarbazolyl, benzoimidazolyl or phenylbenzoimidazolyl, and even more preferably hydrogen, phenyl or carbazolyl. m is 1 or 2. n is an integer less than or equal to (6-m), and from the viewpoint of steric hindrance, it is preferably an integer from 4 to (6-m). In addition, in the compounds represented by each formula above, one or more hydrogen atoms may be replaced with halogen or deuterium.

The compound used as the second component of the present embodiment is preferably, more specifically, 4CzBN, 4CzBN-Ph, 5CzBN, 3Cz2DPhCzBN, 4CzIPN, 2PXZ-TAZ, Cz-TRZ3, BDPCC-TPTA, MA-TA, PA-TA, FA-TA, PXZ-TRZ, DMAC-TRZ, BCzT, DCzTrz, DDCzTRz, spiroAC-TRZ, Ac-HPM, Ac-PPM, Ac-MPM, TCzTrz, TmCzTrz and DCzmCzTrz.

The compound used as the second component of the present invention may be a donor-acceptor type TADF compound represented by D-A in which one donor D and one acceptor A are bonded directly or through a linking group, but a compound having a structure represented by the following formula (DAD1) in which a plurality of donors D are bonded directly or through linking groups to one acceptor A is preferable because the characteristics of the organic electroluminescent device are more excellent.

(D ¹ -L ¹ )nA ¹ (DAD1)

Formula (DAD1) includes a compound represented by the following formula (DAD2).

D ² -L ² -A ² -L ³ -D ³ (DAD2)

In formulas (DAD1) and (DAD2), D ¹ , D ^{2 ,} and D ³ independently represent a donor group. As the donor group, the above-described donor structure can be adopted. A ¹ and A ² independently represent an acceptor group. As the acceptor group, the above-described acceptor structure can be adopted. L ¹ , L ^{2 ,} and L ³ independently represent a single bond or a conjugated linking group. The conjugated linking group is a spacer structure separating the donor group and the acceptor group, and is preferably an arylene having 6 to 18 carbon atoms, more preferably an arylene having 6 to 12 carbon atoms. It is more preferable that L ¹ , L ^{2 ,} and L ³ are each independently phenylene, methylphenylene, or dimethylphenylene. In formula (DAD1), n represents an integer of 2 or more and less than or equal to the maximum number that A ¹ can substitute. n may be selected, for example, within the range of 2 to 10, or within the range of 2 to 6. When n is 2, a compound represented by the formula (DAD2) is obtained. n D ¹ s may be the same or different, and n L ¹ s may be the same or different. Preferred specific examples of the compounds represented by the formulas (DAD1) and (DAD2) include 2PXZ-TAZ or the following compounds, but the second component that can be employed in the present invention is not limited to these compounds.

[Phosphorescent material (assisting dopant)]

In the light-emitting layer, a phosphorescent material may be used as an assisting dopant. In the present specification, an organic electroluminescent device that uses a phosphorescent material as an assisting dopant is sometimes referred to as a phosphorescent assisted device: a phosphorescent-sensitized fluorescent device, a PSF device. A phosphorescent material obtains luminescence from an excited triplet state by utilizing intramolecular spin-orbit interaction (heavy atom effect) by a metal atom. As such a phosphorescent material, for example, a luminescent metal complex can be used. As the luminescent metal complex, for example, compounds represented by the following formula (B-1) and the following formula (B-2) can be exemplified.

In formula (B-1), M is at least one selected from the group consisting of Ir, Pt, Au, Eu, Ru, Re, Ag, and Cu, n is an integer from 1 to 3, and “X-Y” are each independently a bidentate ligand.

In formula (B-2), M is at least one selected from the group consisting of Pt, Re, and Cu, and “W-X-Y-Z” is a four-dentate ligand.

In equation (B-1), from the viewpoint of efficiency and lifespan, M is preferably Ir, and n is preferably 3.

In formula (B-2), Pt is preferable for M from the viewpoint of efficiency and lifespan.

The ligand (X-Y) in formula (B-1) has one or more ligands selected from the group consisting of the following. The ligand (W-X-Y-Z) in formula (B-2) has one or more ligands selected from the group consisting of the following as a part.

During the meal,

--- is combined with the central metal M,

Y is independently BR _e , NR _e , PR _e , O, S, Se, C=O, S=O, SO ₂ , CR _e R _f , SiR _e R _f or GeR _e R _{f ,}

In the ring, each aromatic carbon C-H may be independently substituted with N,

R _e and R _f is They may be arbitrarily condensed or combined to form a ring,

R _a , R _b , R _c and R _d are each independently unsubstituted or 1~Can be substituted up to the maximum number that can be substituted,

R _a , R _b , R _c , R _d , R _e and R _f are each independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl or a combination thereof,

However, any two adjacent substituents in R _a , R _b , R _c and R _d may be condensed or bonded to form a ring, or to form a polydentate ligand.

Compounds represented by the formula (B-1) include, for example, Ir(ppy) ₃ , Ir(ppy) ₂ (acac), Ir(mppy) _{3 ,} Ir(PPy) ₂ (m-bppy), BtpIr(acac), Ir(btp) ₂ (acac), Ir(2-phq) _{3 ,} Hex-Ir (phq) ₃ , Ir(fbi) ₂ (acac), fac-Tris(2-(3-p-xylyl)phenyl)pyridine iridium(III), Eu(dbm) ₃ (Phen), Ir(piq) ₃ , Ir(piq) ₂ (acac), Ir(Fliq) ₂ (acac), Ir(Flq) ₂ (acac), Ru(dtb-bpy) ₃ 2(PF ₆ ), Ir(2-phq) ₃ , Ir(BT) ₂ (acac), Ir(DMP) ₃ , Ir(Mphq) ₃ Ir(phq) ₂ tpy, fac-Ir(ppy) ₂ Pc, Ir(dp)PQ ₂ , Ir(Dpm)(Piq) ₂ , Hex-Ir(piq) ₂ (acac), Hex-Ir(piq) ₃ , Ir(dmpq) ₃ , Examples include Ir(dmpq) ₂ (acac), FPQIrpic, etc.

As compounds represented by formula (B-1), examples thereof include the following compounds.

In addition, iridium complexes described in Japanese Patent Application Publication No. 2006-089398, Japanese Patent Application Publication No. 2006-080419, Japanese Patent Application Publication No. 2005-298483, Japanese Patent Application Publication No. 2005-097263, Japanese Patent Application Publication No. 2004-111379, U.S. Patent Application Publication No. 2019/0051845, etc., or platinum complexes described in Advanced Materials, 26:7116-7121、NPG Asia Materials 13, 53 (2021), Applied Physics Letters, 117, 253301 (2020), Light-Emitting Diode-An Outlook On the Empirical Features and Its Recent Technological Advancements, Chapter 5 may be used.

3-6. Electron injection layer and electron transport layer of organic electroluminescent devices

The electron injection layer (107) plays a role of efficiently injecting electrons moving from the cathode (108) into the light-emitting layer (105) or the electron transport layer (106). The electron transport layer (106) plays a role of efficiently transporting electrons injected from the cathode (108) or electrons injected from the cathode (108) through the electron injection layer (107) to the light-emitting layer (105). The electron transport layer (106) and the electron injection layer (107) are each formed by laminating or mixing one or two or more types of electron transport/injection materials, or by a mixture of an electron transport/injection material and a polymer binder.

The electron injection/transport layer is a layer that injects electrons from the cathode and is responsible for transporting the electrons, and it is desirable that the electron injection efficiency be high and that the injected electrons be transported efficiently. To this end, it is desirable that the electron affinity be high, the electron mobility be high, and furthermore, the stability be excellent, and that impurities that become traps are unlikely to occur during manufacturing and use. However, when considering the transport balance of holes and electrons, if the main role is to efficiently prevent holes from the anode from flowing to the cathode without recombination, even if the electron transport ability is not that high, the effect of improving the luminescence efficiency is equivalent to that of a material with a high electron transport ability. Therefore, the electron injection/transport layer in the present embodiment may also include the function of a layer that can efficiently prevent the movement of holes.

As a material (electron transport material) forming an electron transport layer (106) or an electron injection layer (107), a compound conventionally used as an electron transport compound in a photoconductive material and a known compound used in an electron injection layer and an electron transport layer of an organic EL device can be arbitrarily selected and used. It is also preferable to use the polycyclic aromatic compound of the present invention as a material for an electron transport layer.

It is preferable that the material used in the electron transport layer or the electron injection layer contain at least one selected from compounds composed of an aromatic ring or heteroaromatic ring composed of at least one atom selected from carbon, hydrogen, oxygen, sulfur, silicon, and phosphorus, pyrrole derivatives and condensed-ring derivatives thereof, and metal complexes having electron-accepting nitrogen. Specific examples thereof include condensed-ring aromatic ring derivatives such as naphthalene and anthracene, styryl aromatic ring derivatives represented by 4,4'-bis(diphenylethenyl)biphenyl, perinone derivatives, coumarin derivatives, naphthalimide derivatives, quinone derivatives such as anthraquinone and diphenoquinone, phosphorus oxide derivatives, arylnitrile derivatives, and indole derivatives. Metal complexes having electron-accepting nitrogen include, for example, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes. These materials may be used alone, but may also be used in mixtures with other materials.

In addition, as specific examples of other electron transfer compounds, pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives (such as 1,3-bis[(4-t-butylphenyl)1,3,4-oxadiazolyl]phenylene), thiophene derivatives, triazole derivatives (such as N-naphthyl-2,5-diphenyl-1,3,4-triazole), thiadiazole derivatives, metal complexes of oxine derivatives, quinolinol-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinolines Examples thereof include derivatives (2,2'-bis(benzo[h]quinolin-2-yl)-9,9'-spirobifluorene, etc.), imidazopyridine derivatives, borane derivatives, benzimidazole derivatives (tris(N-phenylbenzoimidazol-2-yl)benzene, etc.), benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, oligopyridine derivatives such as terpyridine, bipyridine derivatives, terpyridine derivatives (1,3-bis(2,2':6',2"-terpyridin-4'-yl)benzene, etc.), naphthyridine derivatives (bis(1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenylphosphineoxide, etc.), aldazine derivatives, carbazole derivatives, indole derivatives, phosphorus oxide derivatives, bisstyryl derivatives, etc.

In addition, metal complexes having electron-accepting nitrogen can be used, and examples thereof include quinolinol-based metal complexes, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes.

The materials described above can be used alone, but can also be mixed with other materials.

Among the materials described above, borane derivatives, pyridine derivatives, fluoranthene derivatives, BO derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and quinolinol-based metal complexes are preferable.

The electron transport layer or electron injection layer may further contain a substance capable of reducing the material forming the electron transport layer or electron injection layer. Various substances can be used as the reducing substance as long as it has a certain reducing property, and for example, at least one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, oxides of alkali metals, halides of alkaline metals, oxides of alkaline earth metals, halides of alkaline earth metals, oxides of rare earth metals, halides of rare earth metals, organic complexes of alkaline earth metals, and organic complexes of rare earth metals can be suitably used.

Preferred reducing substances include alkali metals such as Na (work function 2.36 eV), K (Cu 2.28 eV), Rb (Cu 2.16 eV), or Cs (Cu 1.95 eV), or alkaline earth metals such as Ca (Cu 2.9 eV), Sr (Cu 2.0 to 2.5 eV) or Ba (Cu 2.52 eV), and substances having a work function of 2.9 eV or less are particularly preferable. Among these, more preferable reducing substances are alkali metals such as K, Rb, or Cs, even more preferably Rb or Cs, and most preferably Cs. These alkali metals have particularly high reducing ability, and by adding a relatively small amount to a material forming an electron transport layer or an electron injection layer, it is possible to improve the luminance of the organic EL element or extend its lifetime. In addition, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more alkali metals is also preferable, and in particular, a combination including Cs, for example, a combination of Cs and Na, Cs and K, Cs and Rb or Cs, Na and K is preferable. By including Cs, the reducing ability can be efficiently exhibited, and by adding it to a material forming an electron transport layer or an electron injection layer, the luminance of the organic EL element can be improved or the lifetime can be extended.

3-7. Cathode of organic electroluminescent device

The cathode (108) serves to inject electrons into the light-emitting layer (105) through the electron injection layer (107) and the electron transport layer (106).

The material forming the cathode (108) is not particularly limited as long as it is a material capable of efficiently injecting electrons into the organic layer, but the same material as the material forming the anode (102) can be used. Among them, metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium, and magnesium, or alloys thereof (magnesium-silver alloys, magnesium-indium alloys, aluminum-lithium alloys such as lithium fluoride/aluminum, etc.) are preferable. In order to increase the electron injection efficiency and improve the device characteristics, alloys containing lithium, sodium, potassium, cesium, calcium, magnesium, or these low-work-function metals are effective. However, such low-work-function metals are generally often unstable in the air. To improve this point, for example, a method of using a highly stable electrode by doping a trace amount of lithium, cesium, or magnesium into the organic layer is known. Other dopants that can be used include, but are not limited to, inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide, and cesium oxide.

In addition, for electrode protection, it is preferable to laminate metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, or alloys using these metals, inorganic substances such as silica, titania, and silicon nitride, polyvinyl alcohol, vinyl chloride, hydrocarbon-based polymer compounds, etc. The method for manufacturing these electrodes is not particularly limited as long as conductivity is possible, such as resistance heating, electron beam deposition, sputtering, ion plating, and coating.

3-8. Method for manufacturing organic electroluminescent devices

Each layer constituting the organic EL element can be formed by forming a thin film using the material constituting each layer through a method such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular stacking, printing, spin coating or casting, or coating. There is no particular limitation on the film thickness of each layer formed in this way, and it can be set appropriately depending on the properties of the material, but is usually in the range of 2 nm to 5000 nm. The film thickness can usually be measured using a crystal oscillation film thickness measuring device, etc. When forming a thin film using the vapor deposition method, the deposition conditions vary depending on the type of material, the crystal structure and association structure that the film is intended for, etc. The deposition conditions are generally boat heating temperature +50 to +400°C, vacuum degree 10 ^-6 to 10 ^-3 Pa, deposition speed 0.01 to 50 nm/sec, substrate temperature -150 to +300°C, and film thickness 2 nm to 5 μm. It is preferable to set it appropriately in the range of.

When applying a direct current voltage to the organic EL element obtained in this way, the polarity should be + for the anode and - for the cathode, and when a voltage of about 2 to 40 V is applied, light emission can be observed from the transparent or semitransparent electrode side (anode or cathode and both sides). In addition, this organic EL element also emits light when a pulse current or an alternating current is applied. In addition, the waveform of the applied alternating current may be arbitrary.

Next, as an example of a method for manufacturing an organic EL device, a method for manufacturing an organic EL device composed of an anode/hole injection layer/hole transport layer/emission layer composed of a host material and a dopant material/electron transport layer/electron injection layer/cathode is described.

＜Deposition method＞

On a suitable substrate, a thin film of an anode material is formed by a vapor deposition method or the like to produce an anode, and then thin films of a hole injection layer and a hole transport layer are formed on the anode. A host material and a dopant material are co-deposited thereon to form a thin film to form a light-emitting layer, and an electron transport layer and an electron injection layer are formed on the light-emitting layer, and further, a thin film made of a cathode material is formed by a vapor deposition method or the like to produce a cathode, thereby obtaining a desired organic EL device. Furthermore, in the production of the above-described organic EL device, it is also possible to reverse the production order and produce the device in the order of a cathode, electron injection layer, electron transport layer, light-emitting layer, hole transport layer, hole injection layer, and anode.

＜Wet Tabernacle Method＞

The wet film formation method is carried out by preparing a low molecular weight compound capable of forming each organic layer of an organic EL device as a liquid organic layer forming composition and using this. If there is no suitable organic solvent that dissolves the low molecular weight compound, an organic layer forming composition may be prepared from a polymer compound polymerized with another monomer or main chain polymer having a soluble function as a reactive compound in which a reactive substituent is substituted on the low molecular weight compound.

The wet film-forming method generally forms a film through a coating process of coating an organic layer-forming composition on a substrate and a drying process of removing a solvent from the coated organic layer-forming composition. When the polymer compound has a crosslinkable substituent (also called a crosslinkable polymer compound), it is further crosslinked by this drying process to form a polymer crosslinked body. Depending on the difference in the coating process, a method using a spin coater is called the spin coating method, a method using a slit coater is called the slit coating method, a method using a plate is called the gravure, offset, reverse offset, or flexographic printing method, a method using an inkjet printer is called the inkjet method, and a method of spraying in the shape of a mist is called the spray method. The drying process includes methods such as air drying, heating, and reduced-pressure drying. The drying process may be performed only once, or may be performed multiple times using different methods or conditions. In addition, other methods, such as baking under reduced pressure, may be used in combination.

The wet film deposition method is a film deposition method using a solution, and examples thereof include some printing methods (inkjet methods), spin coating methods or casting methods, and coating methods. Unlike the vacuum deposition method, the wet film deposition method does not require the use of expensive vacuum deposition equipment, and can be formed under atmospheric pressure. In addition, the wet film deposition method allows for large-area and continuous production, which leads to a reduction in manufacturing costs.

On the other hand, compared to the vacuum deposition method, the wet film deposition method sometimes has difficulty in lamination. When producing a laminated film using the wet film deposition method, it is necessary to prevent the lower layer from dissolving due to the upper layer composition, so a composition with controlled solubility, a lower layer crosslinking, and an orthogonal solvent (solvents that do not dissolve in each other) are used. However, even if these techniques are used, it is sometimes difficult to use the wet film deposition method for all film applications.

Therefore, a method is generally adopted to manufacture organic EL devices by using a wet deposition method for only a few layers and a vacuum deposition method for the rest.

For example, the procedure for manufacturing an organic EL device by partially applying a wet film deposition method is shown below.

(Sequence 1) Film formation by vacuum deposition method of anode

(Order 2) Wet film formation of a composition for forming a hole injection layer including a material for a hole injection layer

(Step 3) Wet film formation of a composition for forming a hole transport layer including a material for a hole transport layer

(Step 4) Wet film deposition of a composition for forming a light-emitting layer including a host material and a dopant material

(Step 5) Film formation by vacuum deposition of electron transport layer

(Step 6) Film formation by vacuum deposition of electron injection layer

(Step 7) Film formation by vacuum deposition of cathode

Through this process, an organic EL device composed of an anode/hole injection layer/hole transport layer/emission layer composed of a host material and a dopant material/electron transport layer/electron injection layer/cathode is obtained.

Of course, for the electron transport layer and the electron injection layer, a layer forming composition including a material for the electron transport layer and a material for the electron injection layer may be used to form a film by a wet film forming method, respectively. At this time, it is preferable to use a means for preventing the dissolution of the lower light-emitting layer or a means for forming a film from the cathode side in the opposite order.

＜Other Tabernacle Laws＞

For the film formation of an organic layer-forming composition, laser thermal lithography (LITI) can be used. LITI is a method of heating and depositing a compound attached to a substrate with a laser, and an organic layer-forming composition can be used for a material applied to a substrate.

＜Random Process＞

Before and after each process of the tabernacle, appropriate treatment processes, cleaning processes, and drying processes may be appropriately included. As the treatment processes, for example, exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, cleaning treatment using an appropriate solvent, and heat treatment may be included. In addition, a series of processes for producing a bank may also be included.

Photolithography technology can be used to produce the bank. Available bank materials for photolithography include positive resist materials and negative resist materials. In addition, patternable printing methods such as inkjet printing, gravure offset printing, reverse offset printing, and screen printing can also be used. Permanent resist materials can also be used at this time.

＜Composition for forming organic layer used in wet film deposition method＞

The composition for forming an organic layer is obtained by dissolving a low-molecular-weight compound capable of forming each organic layer of an organic EL device or a high-molecular-weight compound obtained by polymerizing the low-molecular-weight compound in an organic solvent. For example, the composition for forming a light-emitting layer contains, as a first component, at least one dopant material, a polycyclic aromatic compound (or a high-molecular-weight compound thereof), as a second component, at least one host material, and as a third component, at least one organic solvent. The first component functions as a dopant component of the light-emitting layer obtained from the composition, and the second component functions as a host component of the light-emitting layer. The third component functions as a solvent that dissolves the first and second components in the composition, and, when applied, provides a smooth and uniform surface shape by the controlled evaporation rate of the third component itself.

＜Organic solvent＞

The composition for forming an organic layer contains one or more organic solvents. By controlling the evaporation rate of the organic solvent during film formation, the film formation properties and the presence or absence of defects in the film, surface roughness, and smoothness can be controlled and improved. In addition, when film formation using an inkjet method, the meniscus stability in the pinhole of the inkjet head can be controlled and improved to control and improve the discharge properties. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, the electrical characteristics, luminescence characteristics, efficiency, and lifespan of an organic EL device having an organic layer obtained from the composition for forming an organic layer can be improved.

The organic solvent is removed from the film after the film formation by a drying process such as vacuum, depressurization, or heating. When heating is performed, from the viewpoint of improving the coating film formation property, it is preferable to perform the heating at a temperature lower than or equal to the glass transition temperature (Tg) of at least one solute +30°C. Furthermore, from the viewpoint of reducing the residual solvent, it is preferable to perform the heating at a temperature higher than or equal to the glass transition point (Tg) of at least one solute -30°C. Even if the heating temperature is lower than the boiling point of the organic solvent, the film is thin, so the organic solvent is sufficiently removed. Furthermore, drying may be performed multiple times at different temperatures, or multiple drying methods may be used in combination.

(2) Specific examples of organic solvents

Examples of organic solvents used in the composition for forming an organic layer include, but are not limited to, alkylbenzene solvents, phenyl ether solvents, alkyl ether solvents, cyclic ketone solvents, aliphatic ketone solvents, monocyclic ketone solvents, solvents having a diester skeleton, and fluorine-containing solvents. In addition, the solvents may be used alone or in combination.

＜Random ingredients＞

The composition for forming an organic layer may contain optional components as long as the properties thereof are not impaired. Optional components include binders and surfactants.

＜Composition and properties of the composition for forming an organic layer＞

The content of each component in the organic layer-forming composition is determined in consideration of the good solubility, preservation stability and film-forming properties of each component in the organic layer-forming composition, the good film quality of a coating film obtained from the organic layer-forming composition, good discharge properties when using an inkjet method, and the good electrical characteristics, luminescence characteristics, efficiency and lifespan of an organic EL device having an organic layer manufactured using the composition.

The composition for forming an organic layer can be prepared by appropriately selecting and performing stirring, mixing, heating, cooling, dissolving, dispersing, etc. of the above-mentioned components by a known method. In addition, after preparation, filtration, degassing (also called degassing), ion exchange treatment, and inert gas substitution/sealing treatment can be appropriately selected and performed.

＜Application examples of organic electroluminescent devices＞

In addition, the present invention can be applied to a display device having an organic EL element, a lighting device having an organic EL element, etc.

A display device or lighting device equipped with an organic EL element can be manufactured by a known method, such as connecting the organic EL element according to the present embodiment to a known driving device, and can be driven by appropriately using a known driving method, such as direct current driving, pulse driving, or alternating current driving.

As the display device, examples thereof include panel displays such as a color flat panel display, and flexible displays such as a flexible color organic electroluminescence (EL) display (see, for example, Japanese Patent Application Laid-Open No. 10-335066, Japanese Patent Application Laid-Open No. 2003-321546, Japanese Patent Application Laid-Open No. 2004-281086, etc.). In addition, as the display method of the display, examples thereof include a matrix method and a segment method. In addition, a matrix display and a segment display may coexist in the same panel.

In a matrix, pixels for display are arranged two-dimensionally, such as in a grid shape or mosaic shape, and characters or images are displayed as a collection of pixels. The shape and size of the pixels are determined according to the purpose. For example, for image and character display of computers, monitors, and televisions, square pixels with a side of 300㎛ or less are usually used, and in the case of large displays such as display panels, pixels with a side of the order of mm are used. In the case of black and white display, pixels of the same color may be arranged, but in the case of color display, red, green, and blue pixels are arranged and displayed. In this case, there are typically delta types and stripe types. And, as a driving method of this matrix, either a line-sequential driving method or an active matrix can be used. Although line-sequential driving has the advantage of a simple structure, an active matrix may be superior when considering operating characteristics, so this also needs to be distinguished according to the purpose.

In the segment method (type), a pattern is formed to display predetermined information, and a predetermined area is illuminated. Examples include the time or temperature display on a digital clock or thermometer, the operating status display on audio devices or electronic cookers, and the panel display on a car.

As the lighting device, examples thereof include lighting devices such as indoor lighting, and backlights for liquid crystal displays (see, for example, Japanese Patent Laid-Open No. 2003-257621, Japanese Patent Laid-Open No. 2003-277741, Japanese Patent Laid-Open No. 2004-119211, etc.). Backlights are mainly used for the purpose of improving the visibility of display devices that do not self-luminous, and are used in liquid crystal displays, watches, audio devices, automobile panels, signs, and markers. In particular, considering that it is difficult to make a backlight for liquid crystal displays, and especially for computer use where thinning is an issue, to make it thinner because conventional methods consist of fluorescent lamps or light guide plates, the backlight using a light-emitting element according to the present embodiment is characterized by being thin and lightweight.

4. Other organic devices

The polycyclic aromatic compound according to the present invention can be used in the manufacture of organic field effect transistors or organic thin film solar cells, in addition to the organic electroluminescent devices described above.

[Example]

Hereinafter, the present invention will be described more specifically by examples, but the present invention is not limited to these.

＜＜Synthetic example＞＞

Synthetic example (1):

Synthesis of compound (1-1)

A 1.6 M tert-butyllithium pentane solution (1.6 ml) was added to a flask containing compound (S-1-1) (0.72 g) and tert-butylbenzene (7.0 ml) at -30°C under a nitrogen atmosphere. After completion of the dropping, the temperature was increased to 60°C and stirred for 2 hours, and then low-boiling-point components were distilled off from tert-butylbenzene under reduced pressure. After cooling to -30°C, boron tribromide (0.63 g) was added, the temperature was increased to room temperature, and stirred for 0.5 hour. Thereafter, the temperature was cooled to 0°C again, N,N-diisopropylethylamine (0.43 ml) was added, and the temperature was stirred at room temperature until the exotherm subsided, and then the temperature was increased to 120°C and stirred with heating for 3 hours. The reaction solution was cooled to room temperature, and an aqueous sodium acetate solution cooled in an ice bath, followed by heptane, was added to perform liquid separation. Subsequently, after purification using a silica gel short pass column (eluent: toluene), the solvent was distilled off under reduced pressure, and the obtained solid was dissolved in toluene and reprecipitated by adding heptane to obtain compound (1-1) (0.37 g).

The following compounds were synthesized using a method similar to Synthesis Example (1).

Compounds (1-286) to (1-494) were additionally synthesized using a method similar to Synthesis Example (1).

The production of the target product was confirmed by matrix-assisted laser deionization time-of-flight mass spectrometry (MALDI-TOF-MS).

compound M+ Compound (1-1) 693.23 Compound (1-2) 693.23 Compound (1-3) 693.23 Compound (1-4) 749.20 Compounds (1-5) 733.22 Compounds (1-6) 805.17 Compounds (1-7) 773.22 Compound (1-8) 677.25 Compound (1-9) 677.25 Compounds (1-10) 677.25 Compound (1-11) 694.22 Compounds (1-12) 694.22 Compound (1-13) 694.22 Compound (1-14) 691.21 Compounds (1-15) 691.21 Compound (1-16) 691.21 Compound (1-17) 694.22 Compound (1-18) 694.22 Compound (1-19) 694.22 Compound (1-286) 769.26 Compound (1-287) 769.26 Compound (1-288) 694.21 Compound (1-289) 694.21 Compounds (1-290) 693.23 Compound (1-291) 710.19 Compounds (1-292) 937.3 Compounds (1-293) 858.29 Compound (1-294) 770.26 Compounds (1-295) 770.26 Compound (1-296) 858.29 Compound (1-297) 783.24 Compounds (1-298) 799.22 Compounds (1-299) 847.16 Compounds (1-300) 933.32 Compounds (1-301) 949.3 Compound (1-302) 769.26 Compound (1-303) 769.26 Compound (1-304) 694.21 Compounds (1-305) 694.21 Compound (1-306) 710.19 Compound (1-307) 693.23 Compound (1-308) 858.29 Compound (1-309) 937.3 Compounds (1-310) 770.26 Compound (1-311) 770.26 Compounds (1-312) 858.29 Compounds (1-313) 783.24 Compound (1-314) 799.22 Compounds (1-315) 847.16 Compounds (1-316) 933.32 Compound (1-317) 949.3 Compound (1-318) 769.26 Compound (1-319) 769.26 Compounds (1-320) 694.21 Compound (1-321) 694.21 Compounds (1-322) 710.19 Compounds (1-323) 693.23 Compounds (1-324) 858.29 Compounds (1-325) 937.3 Compounds (1-326) 770.26 Compounds (1-327) 770.26 Compounds (1-328) 858.29 Compounds (1-329) 783.24 Compounds (1-330) 799.22 Compound (1-331) 847.16 Compounds (1-332) 933.32 Compounds (1-333) 949.3 Compounds (1-334) 769.26 Compounds (1-335) 769.26 Compounds (1-336) 694.21 Compound (1-337) 694.21 Compounds (1-338) 710.19 Compounds (1-339) 693.23 Compounds (1-340) 858.29 Compound (1-341) 937.3 Compounds (1-342) 770.26 Compounds (1-343) 770.26 Compounds (1-344) 858.29 Compounds (1-345) 783.24 Compounds (1-346) 799.22 Compounds (1-347) 847.16 Compounds (1-348) 933.32 Compounds (1-349) 949.3 Compounds (1-350) 769.26 Compounds (1-351) 769.26 Compounds (1-352) 694.21 Compounds (1-353) 694.21 Compounds (1-354) 710.19 Compounds (1-355) 693.23 Compounds (1-356) 858.29 Compounds (1-357) 937.3 Compounds (1-358) 770.26 Compounds (1-359) 770.26 Compounds (1-360) 858.29 Compounds (1-361) 783.24 Compounds (1-362) 799.22 Compounds (1-363) 847.16 Compounds (1-364) 933.32 Compounds (1-365) 949.3 Compounds (1-366) 860.26 Compounds (1-367) 860.26 Compounds (1-368) 892.21 Compounds (1-369) 858.29 Compounds (1-370) 1168.38 Compound (1-371) 1346.44 Compounds (1-372) 1188.4 Compounds (1-373) 1188.4 Compounds (1-374) 1038.31 Compounds (1-375) 1070.26 Compounds (1-376) 1166.15 Compounds (1-377) 1338.48 Compounds (1-378) 1370.43 Compounds (1-379) 694.21 Compounds (1-380) 694.21 Compound (1-381) 710.19 Compound (1-382) 693.23 Compound (1-383) 848.28 Compound (1-384) 937.3 Compounds (1-385) 858.29 Compound (1-386) 858.29 Compound (1-387) 783.24 Compound (1-388) 799.22 Compounds (1-389) 847.16 Compounds (1-390) 933.32 Compounds (1-391) 949.3 Compounds (1-392) 874.31 Compounds (1-393) 890.28 Compounds (1-394) 873.32 Compounds (1-395) 1038.38 Compounds (1-396) 1117.4 Compounds (1-397) 998.34 Compounds (1-398) 1014.32 Compounds (1-399) 997.35 Compounds (1-400) 1162.41 Compound (1-401) 1241.43 Compound (1-402) 1026.3 Compound (1-403) 1042.27 Compound (1-404) 1025.31 Compounds (1-405) 1190.37 Compound (1-406) 1091.34 Compound (1-407) 1269.39 Compounds (1-408) 1024.33 Compound (1-409) 1040.31 Compounds (1-410) 1023.35 Compound (1-411) 1188.4 Compounds (1-412) 1089.37 Compounds (1-413) 1267.42 Compounds (1-414) 1354.44 Compounds (1-415) 1370.42 Compounds (1-416) 1353.46 Compound (1-417) 1419.48 Compounds (1-418) 784.26 Compounds (1-419) 800.24 Compounds (1-420) 783.28 Compound (1-421) 948.33 Compounds (1-422) 1027.35 Compounds (1-423) 846.28 Compounds (1-424) 862.25 Compounds (1-425) 845.29 Compound (1-426) 1010.35 Compounds (1-427) 1089.37 Compounds (1-428) 860.26 Compounds (1-429) 876.23 Compounds (1-430) 859.27 Compound (1-431) 1024.33 Compounds (1-432) 925.29 Compounds (1-433) 1103.35 Compounds (1-434) 859.27 Compounds (1-435) 875.25 Compounds (1-436) 858.29 Compound (1-437) 1023.35 Compounds (1-438) 924.31 Compounds (1-439) 1102.36 Compounds (1-440) 1024.33 Compound (1-441) 1040.31 Compounds (1-442) 1023.35 Compounds (1-443) 1188.4 Compounds (1-444) 1089.37 Compounds (1-445) 1267.42 Compounds (1-446) 769.26 Compounds (1-447) 769.26 Compounds (1-448) 694.21 Compounds (1-449) 694.21 Compounds (1-450) 710.19 Compounds (1-451) 937.3 Compounds (1-452) 858.29 Compounds (1-453) 770.26 Compounds (1-454) 770.26 Compounds (1-455) 769.26 Compounds (1-456) 769.26 Compounds (1-457) 694.21 Compounds (1-458) 694.21 Compounds (1-459) 710.19 Compounds (1-460) 693.23 Compounds (1-461) 937.3 Compounds (1-462) 858.29 Compounds (1-463) 770.26 Compounds (1-464) 770.26 Compounds (1-465) 769.26 Compounds (1-466) 769.26 Compounds (1-467) 694.21 Compounds (1-468) 694.21 Compounds (1-469) 786.22 Compounds (1-470) 710.19 Compounds (1-471) 693.23 Compounds (1-472) 937.3 Compounds (1-473) 858.29 Compounds (1-474) 770.26 Compounds (1-475) 770.26 Compounds (1-476) 770.26 Compounds (1-477) 770.26 Compounds (1-478) 695.21 Compounds (1-479) 695.21 Compounds (1-480) 711.19 Compound (1-481) 938.3 Compounds (1-482) 859.28 Compounds (1-483) 771.25 Compound (1-484) 771.25 Compounds (1-485) 770.26 Compound (1-486) 770.26 Compound (1-487) 695.21 Compounds (1-488) 695.21 Compounds (1-489) 711.19 Compounds (1-490) 694.22 Compounds (1-491) 938.3 Compounds (1-492) 859.28 Compounds (1-493) 771.25 Compounds (1-494) 771.25

＜＜Manufacturing and Evaluation of Organic EL Devices＞＞

Each organic EL device of TAF and PSF was manufactured using each compound of the present invention and the comparative compound.

＜TADF Composition: Examples 1-1 to 1-19 and Comparative Example 1-1＞

ITO(50nm)/HAT-CN(10nm)/HT-1(60nm)/SiCzCz(5nm)/SiCzCz:Each compound listed in Table 2:new-DABNA(60:39:1)(35nm)/mSiTrz(5nm)/mSiTrz:Liq(1:1)(30nm)/LiF(1nm)/Al(100nm)

A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Optoscience Co., Ltd.) on which ITO was sputtered to a thickness of 200 nm and polished to a thickness of 50 nm was used as a transparent support substrate. This transparent support substrate was fixed to a substrate holder of a commercially available deposition device (manufactured by Showa Vacuum Co., Ltd.), and a molybdenum deposition boat containing HAT-CN, HT-1, SiCzCz, each of the compounds listed in Table 2, new-DABNA, mSiTrz, and Liq, and a tungsten deposition boat containing LiF and aluminum, respectively, were mounted.

The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was decompressed to 5×10 ^-4 Pa, and first, HAT-CN was heated and deposited to a film thickness of 10 nm to form a hole injection layer. Next, HT-1 was heated and deposited to a film thickness of 60 nm to form a hole transport layer (1), and further, SiCzCz was heated and deposited to a film thickness of 5 nm to form a hole transport layer (2). Next, SiCzCz, each compound listed in Table 2, and new-DABNA were simultaneously heated and deposited to a film thickness of 35 nm to form a light-emitting layer. The deposition rate was controlled so that the mass ratio of SiCzCz, each compound listed in Table 2, and new-DABNA was approximately 60:39:1. Next, mSiTrz was heated and deposited to a film thickness of 5 nm to form an electron transport layer (1), and further, mSiTrz and Liq were heated and deposited to a film thickness of 30 nm to form an electron transport layer (2). The deposition rate was controlled so that the mass ratio of SiTrz and Liq was approximately 1:1. The deposition rate of each layer was 0.01 to 1 nm/sec. Thereafter, LiF was heated and deposited at a deposition rate of 0.01 to 0.1 nm/sec so that the film thickness was 1 nm, and then aluminum was heated and deposited to a film thickness of 100 nm to form a cathode, thereby obtaining an organic EL device. At this time, the deposition rate of aluminum was controlled to 1 to 10 nm/sec. In addition, SiCzCz of the emitting layer corresponds to a hole-transporting host material, and each compound listed in Table 2 corresponds to an electron-transporting host material.

＜TAF Composition: Examples 2-1 to 2-19 and Comparative Example 2-1＞

ITO(50nm)/HAT-CN(10nm)/HT-1(60nm)/SiCzCz(5nm)/SiCzCz:Each compound listed in Table 2:TADF-1:new-DABNA(60:26:13:1)(35nm)/mSiTrz(5nm)/mSiTrz:Liq(1:1)(30nm)/LiF(1nm)/Al(100nm)

Except for the emitting layer, it was fabricated in the same manner as the TADF composition. In the emitting layer, SiCzCz and each compound listed in Table 2, (TADF-1) and new-DABNA were simultaneously heated and deposited to a film thickness of 35 nm. The deposition rate was controlled so that the mass ratio of SiCzCz and each compound listed in Table 2, (TADF-1) and new-DABNA was approximately 60:26:13:1.

＜PSF Composition: Example 3-1 to Example 3-228 and Comparative Example 3-1＞

ITO(50nm)/HAT-CN(10nm)/HT-1(60nm)/SiCzCz(5nm)/SiCzCz:Each compound listed in Table 2:PtON7:new-DABNA(60:26:13:1)(35nm)/mSiTrz(5nm)/mSiTrz:Liq(1:1)(30nm)/LiF(1nm)/Al(100nm)

The above TAF configuration (TADF-1) was replaced with PtON7, and the device was fabricated in the same manner.

The chemical structures of the compounds used in the manufacture of each of the above elements are shown below.

[evaluation]

Evaluation items include driving voltage (V), emission wavelength (nm), CIE chromaticity (x, y), external quantum efficiency (%), maximum wavelength (nm) and half width (nm) of the emission spectrum. For example, values at 1000 cd/m ² emission can be used for these evaluation items.

The quantum efficiency of a light-emitting device includes internal quantum efficiency and external quantum efficiency. The internal quantum efficiency represents the rate at which external energy injected as electrons (or holes) into the light-emitting layer of the light-emitting device is purely converted into photons. On the other hand, the external quantum efficiency is calculated based on the amount of these photons emitted to the outside of the light-emitting device, and since some of the photons generated in the light-emitting layer are absorbed inside the light-emitting device or continue to be reflected and are not emitted to the outside of the light-emitting device, the external quantum efficiency is lower than the internal quantum efficiency.

The method for measuring spectral radiance (emission spectrum) and external quantum efficiency is as follows. Using a voltage/current generator R6144 manufactured by Advantest, a voltage is applied so that the device's luminance becomes 1000 cd/ ^m2 to cause the device to emit light. Using a spectroradiometer SR-3AR manufactured by TOPCON, the spectral radiance in the visible region is measured perpendicular to the light-emitting surface. Assuming that the light-emitting surface is a completely diffuse surface, the value of the spectral radiance of each measured wavelength component is divided by the wavelength energy and multiplied by π, which is the number of photons at each wavelength. Then, the number of photons in the entire observed wavelength range is integrated, which is the total number of photons emitted from the device. The number obtained by dividing the applied current value by the small charge is the number of carriers injected into the device, and the number obtained by dividing the total number of photons emitted from the device by the number of carriers injected into the device is the external quantum efficiency. Additionally, the half-width of the emission spectrum is calculated as the width between the upper and lower wavelengths at which the intensity is 50%, centered on the maximum emission wavelength.

The ITO electrode was used as the anode and the LiF/aluminum electrode as the cathode, and a DC voltage was applied, and the characteristics at 1000 cd/ ^m2 luminescence were measured. In addition, the time (lifespan) for maintaining luminance of 50% or more of the initial luminance was measured. In addition, the luminescence peaks of the devices were all in the range of 469 to 475 nm.

The results are shown in Table 2.

　 Component composition compound External quantum efficiency (%) Lifespan (hr) Comparative Example 1-1 TADF SiTrzCz2 23.3 6 Example 1-1 TADF Compound (1-1) 23.5 7 Example 1-2 TADF Compound (1-2) 24.0 8 Example 1-3 TADF Compound (1-3) 23.5 7 Example 1-4 TADF Compound (1-4) 24.6 8 Example 1-5 TADF Compounds (1-5) 25.3 9 Example 1-6 TADF Compounds (1-6) 25.2 9 Example 1-7 TADF Compounds (1-7) 25.6 8 Example 1-8 TADF Compound (1-8) 24.9 9 Example 1-9 TADF Compound (1-9) 24.6 8 Example 1-10 TADF Compounds (1-10) 25.6 9 Example 1-11 TADF Compound (1-11) 23.8 8 Example 1-12 TADF Compounds (1-12) 25.8 8 Example 1-13 TADF Compound (1-13) 25.7 8 Example 1-14 TADF Compound (1-14) 25.6 9 Example 1-15 TADF Compounds (1-15) 24.7 8 Example 1-16 TADF Compound (1-16) 23.7 8 Example 1-17 TADF Compound (1-17) 26.2 9 Example 1-18 TADF Compound (1-18) 27.6 9 Example 1-19 TADF Compound (1-19) 26.6 9 Comparative Example 2-1 TAF SiTrzCz2 26.1 40 Example 2-1 TAF Compound (1-1) 27.0 44 Example 2-2 TAF Compound (1-2) 26.6 49 Example 2-3 TAF Compound (1-3) 28.1 51 Example 2-4 TAF Compound (1-4) 27.2 53 Example 2-5 TAF Compounds (1-5) 27.1 59 Example 2-6 TAF Compounds (1-6) 28.6 51 Example 2-7 TAF Compounds (1-7) 28.9 59 Example 2-8 TAF Compound (1-8) 28.3 56 Example 2-9 TAF Compound (1-9) 27.7 61 Example 2-10 TAF Compounds (1-10) 28.4 62 Example 2-11 TAF Compound (1-11) 27.7 58 Example 2-12 TAF Compounds (1-12) 28.8 59 Example 2-13 TAF Compound (1-13) 28.8 52 Example 2-14 TAF Compound (1-14) 28.7 60 Example 2-15 TAF Compounds (1-15) 27.4 60 Example 2-16 TAF Compound (1-16) 28.3 61 Example 2-17 TAF Compound (1-17) 30.7 59 Example 2-18 TAF Compound (1-18) 28.4 61 Example 2-19 TAF Compound (1-19) 29.2 66 Comparative Example 3-1 PSF SiTrzCz2 31.2 94 Example 3-1 PSF Compound (1-1) 32.0 115 Example 3-2 PSF Compound (1-2) 32.7 119 Example 3-3 PSF Compound (1-3) 31.9 118 Example 3-4 PSF Compound (1-4) 34.7 135 Example 3-5 PSF Compounds (1-5) 32.9 122 Example 3-6 PSF Compounds (1-6) 33.7 137 Example 3-7 PSF Compounds (1-7) 33.2 135 Example 3-8 PSF Compound (1-8) 32.7 139 Example 3-9 PSF Compound (1-9) 33.0 135 Example 3-10 PSF Compounds (1-10) 32.1 120 Example 3-11 PSF Compound (1-11) 34.5 140 Example 3-12 PSF Compounds (1-12) 33.1 124 Example 3-13 PSF Compound (1-13) 32.0 125 Example 3-14 PSF Compound (1-14) 32.5 125 Example 3-15 PSF Compounds (1-15) 33.0 130 Example 3-16 PSF Compound (1-16) 33.2 135 Example 3-17 PSF Compound (1-17) 36.4 158 Example 3-18 PSF Compound (1-18) 36.6 162 Example 3-19 PSF Compound (1-19) 33.7 137 Example 3-20 PSF Compound (1-286) 36.1 145 Example 3-21 PSF Compound (1-287) 34.1 141 Example 3-22 PSF Compound (1-288) 31.6 141 Example 3-23 PSF Compound (1-289) 33.0 129 Example 3-24 PSF Compounds (1-290) 34.1 143 Example 3-25 PSF Compound (1-291) 34.4 141 Example 3-26 PSF Compounds (1-292) 31.8 147 Example 3-27 PSF Compounds (1-293) 34.1 135 Example 3-28 PSF Compound (1-294) 33.5 130 Example 3-29 PSF Compounds (1-295) 31.0 137 Example 3-30 PSF Compound (1-296) 33.2 141 Example 3-31 PSF Compound (1-297) 32.5 152 Example 3-32 PSF Compounds (1-298) 31.0 135 Example 3-33 PSF Compounds (1-299) 32.0 127 Example 3-34 PSF Compounds (1-300) 33.7 143 Example 3-35 PSF Compounds (1-301) 33.7 145 Example 3-36 PSF Compound (1-302) 34.7 134 Example 3-37 PSF Compound (1-303) 33.0 147 Example 3-38 PSF Compound (1-304) 33.7 133 Example 3-39 PSF Compounds (1-305) 34.4 146 Example 3-40 PSF Compound (1-306) 34.8 145 Example 3-41 PSF Compound (1-307) 33.2 132 Example 3-42 PSF Compound (1-308) 32.3 140 Example 3-43 PSF Compound (1-309) 32.0 139 Example 3-44 PSF Compounds (1-310) 34.1 138 Example 3-45 PSF Compound (1-311) 33.4 134 Example 3-46 PSF Compounds (1-312) 33.9 148 Example 3-47 PSF Compounds (1-313) 33.9 145 Example 3-48 PSF Compound (1-314) 32.0 120 Example 3-49 PSF Compounds (1-315) 32.0 121 Example 3-50 PSF Compounds (1-316) 32.7 141 Example 3-51 PSF Compound (1-317) 35.0 152 Example 3-52 PSF Compound (1-318) 32.5 127 Example 3-53 PSF Compound (1-319) 31.0 120 Example 3-54 PSF Compounds (1-320) 34.4 138 Example 3-55 PSF Compound (1-321) 33.5 135 Example 3-56 PSF Compounds (1-322) 33.7 134 Example 3-57 PSF Compounds (1-323) 32.8 146 Example 3-58 PSF Compounds (1-324) 32.0 123 Example 3-59 PSF Compounds (1-325) 32.0 126 Example 3-60 PSF Compounds (1-326) 33.3 135 Example 3-61 PSF Compounds (1-327) 33.1 133 Example 3-62 PSF Compounds (1-328) 31.9 134 Example 3-63 PSF Compounds (1-329) 31.2 134 Example 3-64 PSF Compounds (1-330) 33.0 130 Example 3-65 PSF Compound (1-331) 32.4 132 Example 3-66 PSF Compounds (1-332) 32.4 142 Example 3-67 PSF Compounds (1-333) 34.0 133 Example 3-68 PSF Compounds (1-334) 32.8 134 Example 3-69 PSF Compounds (1-335) 32.2 126 Example 3-70 PSF Compounds (1-336) 33.4 126 Example 3-71 PSF Compound (1-337) 32.9 156 Example 3-72 PSF Compounds (1-338) 35.5 148 Example 3-73 PSF Compounds (1-339) 34.1 145 Example 3-74 PSF Compounds (1-340) 33.2 144 Example 3-75 PSF Compound (1-341) 33.2 140 Example 3-76 PSF Compounds (1-342) 33.7 144 Example 3-77 PSF Compounds (1-343) 33.8 139 Example 3-78 PSF Compounds (1-344) 35.0 138 Example 3-79 PSF Compounds (1-345) 32.9 141 Example 3-80 PSF Compounds (1-346) 33.2 144 Example 3-81 PSF Compounds (1-347) 34.2 137 Example 3-82 PSF Compounds (1-348) 35.9 137 Example 3-83 PSF Compounds (1-349) 35.9 124 Example 3-84 PSF Compounds (1-350) 34.4 145 Example 3-85 PSF Compounds (1-351) 32.2 154 Example 3-86 PSF Compounds (1-352) 33.4 130 Example 3-87 PSF Compounds (1-353) 33.1 129 Example 3-88 PSF Compounds (1-354) 33.7 158 Example 3-89 PSF Compounds (1-355) 33.3 140 Example 3-90 PSF Compounds (1-356) 34.4 135 Example 3-91 PSF Compounds (1-357) 33.6 143 Example 3-92 PSF Compounds (1-358) 33.5 157 Example 3-93 PSF Compounds (1-359) 33.3 136 Example 3-94 PSF Compounds (1-360) 34.5 142 Example 3-95 PSF Compounds (1-361) 34.2 138 Example 3-96 PSF Compounds (1-362) 33.0 143 Example 3-97 PSF Compounds (1-363) 35.3 128 Example 3-98 PSF Compounds (1-364) 33.9 138 Example 3-99 PSF Compounds (1-365) 32.6 138 Example 3-100 PSF Compounds (1-366) 32.2 132 Example 3-101 PSF Compounds (1-367) 32.2 143 Example 3-102 PSF Compounds (1-368) 36.1 147 Example 3-103 PSF Compounds (1-369) 32.4 142 Example 3-104 PSF Compounds (1-370) 32.3 152 Example 3-105 PSF Compound (1-371) 32.4 144 Example 3-106 PSF Compounds (1-372) 30.0 113 Example 3-107 PSF Compounds (1-373) 33.9 140 Example 3-108 PSF Compounds (1-374) 34.1 142 Example 3-109 PSF Compounds (1-375) 32.2 136 Example 3-110 PSF Compounds (1-376) 33.7 136 Example 3-111 PSF Compounds (1-377) 31.5 140 Example 3-112 PSF Compounds (1-378) 35.1 128 Example 3-113 PSF Compounds (1-379) 34.1 141 Example 3-114 PSF Compounds (1-380) 32.8 145 Example 3-115 PSF Compound (1-381) 34.7 137 Example 3-116 PSF Compound (1-382) 32.0 116 Example 3-117 PSF Compound (1-383) 33.8 133 Example 3-118 PSF Compound (1-384) 33.5 145 Example 3-119 PSF Compounds (1-385) 33.0 130 Example 3-120 PSF Compound (1-386) 33.6 139 Example 3-121 PSF Compound (1-387) 35.4 139 Example 3-122 PSF Compound (1-388) 34.5 136 Example 3-123 PSF Compounds (1-389) 33.3 144 Example 3-124 PSF Compounds (1-390) 31.9 135 Example 3-125 PSF Compounds (1-391) 33.1 134 Example 3-126 PSF Compounds (1-392) 32.9 154 Example 3-127 PSF Compounds (1-393) 31.0 110 Example 3-128 PSF Compounds (1-394) 35.3 142 Example 3-129 PSF Compounds (1-395) 32.7 141 Example 3-130 PSF Compounds (1-396) 32.5 142 Example 3-131 PSF Compounds (1-397) 35.1 137 Example 3-132 PSF Compounds (1-398) 33.9 150 Example 3-133 PSF Compounds (1-399) 33.4 154 Example 3-134 PSF Compounds (1-400) 33.9 144 Example 3-135 PSF Compound (1-401) 34.4 134 Example 3-136 PSF Compound (1-402) 32.2 138 Example 3-137 PSF Compound (1-403) 32.8 148 Example 3-138 PSF Compound (1-404) 32.7 134 Example 3-139 PSF Compounds (1-405) 34.4 138 Example 3-140 PSF Compound (1-406) 33.5 150 Example 3-141 PSF Compound (1-407) 31.5 130 Example 3-142 PSF Compounds (1-408) 32.5 143 Example 3-143 PSF Compound (1-409) 33.0 134 Example 3-144 PSF Compounds (1-410) 32.6 140 Example 3-145 PSF Compound (1-411) 34.9 146 Example 3-146 PSF Compounds (1-412) 30.6 132 Example 3-147 PSF Compounds (1-413) 33.5 122 Example 3-148 PSF Compounds (1-414) 34.0 137 Example 3-149 PSF Compounds (1-415) 32.9 144 Example 3-150 PSF Compounds (1-416) 33.3 143 Example 3-151 PSF Compound (1-417) 34.3 147 Example 3-152 PSF Compounds (1-418) 32.8 155 Example 3-153 PSF Compounds (1-419) 33.6 139 Example 3-154 PSF Compounds (1-420) 31.5 139 Example 3-155 PSF Compound (1-421) 32.3 145 Example 3-156 PSF Compounds (1-422) 33.1 148 Example 3-157 PSF Compounds (1-423) 33.0 134 Example 3-158 PSF Compounds (1-424) 34.6 139 Example 3-159 PSF Compounds (1-425) 33.9 142 Example 3-160 PSF Compound (1-426) 34.0 149 Example 3-161 PSF Compounds (1-427) 33.6 139 Example 3-162 PSF Compounds (1-428) 33.9 126 Example 3-163 PSF Compounds (1-429) 34.8 134 Example 3-164 PSF Compounds (1-430) 32.8 139 Example 3-165 PSF Compound (1-431) 33.1 137 Example 3-166 PSF Compounds (1-432) 31.3 148 Example 3-167 PSF Compounds (1-433) 34.0 135 Example 3-168 PSF Compounds (1-434) 34.1 142 Example 3-169 PSF Compounds (1-435) 34.1 152 Example 3-170 PSF Compounds (1-436) 34.4 145 Example 3-171 PSF Compound (1-437) 34.2 136 Example 3-172 PSF Compounds (1-438) 32.5 142 Example 3-173 PSF Compounds (1-439) 33.6 129 Example 3-174 PSF Compounds (1-440) 32.6 144 Example 3-175 PSF Compound (1-441) 33.5 132 Example 3-176 PSF Compounds (1-442) 34.5 139 Example 3-177 PSF Compounds (1-443) 31.5 145 Example 3-178 PSF Compounds (1-444) 33.0 134 Example 3-179 PSF Compounds (1-445) 34.2 124 Example 3-180 PSF Compounds (1-446) 33.4 151 Example 3-181 PSF Compounds (1-447) 32.7 149 Example 3-182 PSF Compounds (1-448) 34.5 148 Example 3-183 PSF Compounds (1-449) 32.5 147 Example 3-184 PSF Compounds (1-450) 33.4 156 Example 3-185 PSF Compounds (1-451) 34.5 137 Example 3-186 PSF Compounds (1-452) 33.1 137 Example 3-187 PSF Compounds (1-453) 33.6 145 Example 3-188 PSF Compounds (1-454) 33.9 146 Example 3-189 PSF Compounds (1-455) 33.3 140 Example 3-190 PSF Compounds (1-456) 32.5 132 Example 3-191 PSF Compounds (1-457) 33.8 145 Example 3-192 PSF Compounds (1-458) 32.8 148 Example 3-193 PSF Compounds (1-459) 33.7 139 Example 3-194 PSF Compounds (1-460) 32.8 134 Example 3-195 PSF Compounds (1-461) 35.1 148 Example 3-196 PSF Compounds (1-462) 34.3 143 Example 3-197 PSF Compounds (1-463) 33.7 150 Example 3-198 PSF Compounds (1-464) 33.7 139 Example 3-199 PSF Compounds (1-465) 32.5 137 Example 3-200 PSF Compounds (1-466) 34.1 124 Example 3-201 PSF Compounds (1-467) 32.7 145 Example 3-202 PSF Compounds (1-468) 33.8 138 Example 3-203 PSF Compounds (1-469) 33.3 133 Example 3-204 PSF Compounds (1-470) 35.3 141 Example 3-205 PSF Compound (1-471) 34.5 140 Example 3-206 PSF Compounds (1-472) 32.5 141 Example 3-207 PSF Compounds (1-473) 31.8 147 Example 3-208 PSF Compounds (1-474) 34.2 136 Example 3-209 PSF Compounds (1-475) 34.0 136 Example 3-210 PSF Compounds (1-476) 32.5 140 Example 3-211 PSF Compounds (1-477) 33.7 138 Example 3-212 PSF Compounds (1-478) 34.6 143 Example 3-213 PSF Compounds (1-479) 33.6 126 Example 3-214 PSF Compounds (1-480) 32.7 141 Example 3-215 PSF Compound (1-481) 34.6 143 Example 3-216 PSF Compounds (1-482) 35.6 157 Example 3-217 PSF Compounds (1-483) 33.4 145 Example 3-218 PSF Compound (1-484) 34.8 142 Example 3-219 PSF Compounds (1-485) 33.8 145 Example 3-220 PSF Compound (1-486) 33.0 154 Example 3-221 PSF Compound (1-487) 34.8 138 Example 3-222 PSF Compounds (1-488) 34.0 135 Example 3-223 PSF Compounds (1-489) 32.3 151 Example 3-224 PSF Compounds (1-490) 33.3 151 Example 3-225 PSF Compounds (1-491) 31.7 138 Example 3-226 PSF Compounds (1-492) 34.8 147 Example 3-227 PSF Compounds (1-493) 35.9 139 Example 3-228 PSF Compounds (1-494) 33.8 138

From the obtained results, it can be seen that the device of the example has high efficiency and long life compared to the device of the comparative example having a corresponding skeleton.

100 Organic Electroluminescent Devices
101 substrate
102 Bipolar
103 Hole injection layer
104 hole transport layer
105 luminous layer
106 electron transport layer
107 electron injection layer
108 cathode

Claims (16)

A polycyclic aromatic compound represented by formula (1) and comprising at least one partial structure represented by formula (Xa-1) and at least one partial structure represented by formula (Xb-1);

In equation (1),
Ring A, ring B and ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,
Among the formulas (Xa-1),
X ^a is C, Si, Ge or Sn,
The AR1 ring, AR2 ring, AR3 ring and AR4 ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR1 ring, AR2 ring, AR3 ring and AR4 ring may each be connected to any one of the other AR1 ring, AR2 ring, AR3 ring and AR4 ring by a single bond or a connecting group.
One or two selected from the group consisting of AR1 ring, AR2 ring, AR3 ring and AR4 ring,
Is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the A ring, B ring or C ring through a single bond, or
is bonded to ring A, ring B or ring C, or is bonded to an aryl ring or heteroaryl ring of ring D, ring E or AR5 in formula (Xb-1) that shares one ring with ring A, ring B or ring C, through a single bond,
Sharing a ring with Ring A, Ring B or Ring C, or
A ring is bonded to ring A, ring B or ring C, or shares a ring with ring D, ring E or AR5 among formula (Xb-1) that shares a ring with ring A, ring B or ring C,
Among the formulas (Xb-1),
D ring and E ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,
X ^b is a divalent group represented by the formula (Xb-R5), >O or >S,

Among the formulas (Xb-R5),
The two #s are the bonding positions with the D ring and the E ring, respectively.
The AR5 ring is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and the AR5 ring may be connected to the D ring and/or the E ring by a single bond or a connecting group.
One or two selected from the group consisting of D ring, E ring and AR5 ring,
Is bonded to a ring constituent atom of an aryl ring or heteroaryl ring in the A ring, B ring or C ring through a single bond, or
Is bonded to ring A, ring B or ring C, or is bonded to an aryl ring or heteroaryl ring in the AR1 ring, AR2 ring, AR3 ring or AR4 ring in formula (Xa-1) that shares one ring with ring A, ring B or ring C, through a single bond,
Sharing a ring with Ring A, Ring B or Ring C, or
A ring is shared with an AR1 ring, AR2 ring, AR3 ring or AR4 ring among formula (Xa-1) which is bound to an A ring, a B ring or a C ring, or shares a ring with an A ring, a B ring or a C ring,
In formula (1), one or more hydrogens may be replaced with deuterium, one or more nitrogens may be replaced with nitrogen-15 ( ¹⁵ N), one or more sulfurs may be replaced with sulfur-33 ( ³³ S), sulfur-34 ( ³⁴ S), or sulfur-36 ( ³⁶ S), one or more oxygens may be replaced with oxygen-17 ( ¹⁷ O) or oxygen-18 ( ¹⁸ O), one or more carbons may be replaced with carbon-13 ( ¹³ C), and one or more borons may be replaced with boron-11 ( ¹¹ B). In the first paragraph,
A polycyclic aromatic compound in which at least one ring selected from the group consisting of an AR1 ring, an AR2 ring, an AR3 ring and an AR4 ring is bonded to an A ring, a B ring or a C ring, or a D ring, an E ring or an AR5 ring in formula (Xb-1). In the first paragraph,
A polycyclic aromatic compound represented by formula (1a), formula (1b), or formula (1c), and comprising at least one partial structure represented by formula (Xa-2) and at least one partial structure represented by formula (Xb-2);

Among equations (1a), (1b), (1c), (Xa-2), and (Xb-2),
One or two selected from the group consisting of Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring,
is bonded to Z in the a ring, b ring or c ring through a single bond, or
In the partial structure represented by formula (Xb-2) which is bonded to Z among the a ring, b ring or c ring, it is bonded to the d ring, e ring or AR5 ring, or
Sharing a ring with ring A, ring B or ring C, or
is bonded to ring a, ring b or ring c, or shares a ring with ring d, ring e or AR5 among formula (Xb-2) that shares a ring with ring a, ring b or ring c,
One or two selected from the group consisting of d ring, e ring and AR5 ring,
is bonded to Z in the a ring, b ring or c ring through a single bond, or
In the partial structure represented by formula (Xa-2) which is bonded to Z in the a ring, b ring or c ring, or in the Ar ¹ ring, Ar ² ring, Ar ³ ring or Ar ⁴ ring,
Sharing a ring with ring A, ring B or ring C, or
A ring is shared with Ar ¹ ring, Ar ² ring, Ar 3 ring or Ar ⁴ ring among formula (Xa-2) which is bound to ring a, ring b or ring c, or shares a ring with ring ^a, ring b or ring c,
The Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring may each be connected to any one of the other Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring by a single bond or a connecting group,
Y ¹ and Y ² are each independently >NR ^NY , >C(-R ^CY ) ₂ , >O, >Si(-R ^IY ) ₂ , >S or >Se, and R ^NY , R ^CY and R ^IY are each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, and two R ^CY may be combined with each other to form a ring, and two R ^IY may be combined with each other to form a ring,
Z is a carbon atom having a bond with another ring, or -C(-R ^Z )= or -N=, R ^Z is hydrogen or a substituent, provided that two adjacent Z constituting the e ring in formula (Xb-2) may be carbon atoms each bonded to two * of formula (Xb-2-e), and X ^b in formula (Xb-2-e) is a divalent group represented by formula (Xb-R5), >O, >C(-R ^CX ) ₂ , >Si(-R ^IX ) ₂ , >S or >Se, and R ^CX are each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl or a substituted or unsubstituted cycloalkyl, and two R ^CX may be bonded to each other to form a ring, and R ^IX are each independently hydrogen, a substituted or unsubstituted aryl, a substituted or unsubstituted Heteroaryl, substituted or unsubstituted alkyl or substituted or unsubstituted cycloalkyl, and two R ^IX may be combined with each other to form a ring,
When X ^b is a divalent group represented by the formula (XB-R5), the AR5 ring is a six-membered ring. In the third paragraph,
A polycyclic aromatic compound represented by formula (1b) or formula (1c). In the third paragraph,
A polycyclic aromatic compound in which X ^a in formula (Xa-2) is C, Ge or Sn, and no two of the Ar ¹ ring, Ar ² ring, Ar ³ ring and Ar ⁴ ring are connected to each other. In the third paragraph,
A polycyclic aromatic compound in which X ^a is Si in formula (Xa-2) and at least one of Z is -N=. In the third paragraph,
A polycyclic aromatic compound in which X ^a is Si in the formula (Xa-2), and two or more of the Ar ¹ ring, the Ar ² ring, the Ar ³ ring, and the Ar ⁴ ring are connected to each other. In the third paragraph,
A polycyclic aromatic compound in which at least one of Z in formula (Xb-2) is -N=. In the third paragraph,
A polycyclic aromatic compound represented by any one of the following formulas.

In the third paragraph,
A polycyclic aromatic compound represented by any one of the following formulas.












In the third paragraph,
A polycyclic aromatic compound represented by any one of the following formulas.
An organic electroluminescent device having a pair of electrodes consisting of an anode and a cathode and an organic layer disposed between the pair of electrodes, wherein the organic layer contains a polycyclic aromatic compound according to any one of claims 1 to 11. In Article 12,
An organic electroluminescent device, wherein the organic layer is a light-emitting layer. In Article 13,
An organic electroluminescent device, wherein the polycyclic aromatic compound is an electron-transporting host material, and the light-emitting layer further comprises a hole-transporting host material and a dopant material. In Article 14,
An organic electroluminescent device, wherein the light-emitting layer further comprises at least one selected from the group consisting of thermally activated delayed fluorescent materials and phosphorescent materials. A display device or lighting device having an organic electroluminescent element described in Article 12.