TW202446824A - High molecular weight compound and organic electroluminescence device - Google Patents

Abstract

It is an object of the present invention to provide a polymer material having excellent hole injection/transport performance, electron blocking capability, and high stability in a thin-film state. Further, another object of the present invention is to provide an organic EL device that includes an organic layer (thin film) formed of the polymer material and has high light emission efficiency and a long lifetime. A high-molecular-weight compound, including: at least a carbazole structural unit having a thermal crosslinking group Q, which is represented by the following general formula (1), the high-molecular-weight compound having a weight average molecular weight of 10,000 or more and less than 1,000,000 in terms of polystyrene.

Description

High molecular weight compound and organic electroluminescent element

The present invention relates to a high molecular weight compound suitable for an organic electroluminescent element (organic EL element) which is a self-luminescent element applicable to various display devices, and the element thereof.

Since organic EL elements are self-luminous elements, they are brighter than liquid crystal elements, have excellent visibility, and can produce vivid displays, so active research is underway.

Organic EL elements have a structure in which a thin film (organic layer) of an organic compound is sandwiched between an anode and a cathode. The methods for forming thin films are roughly divided into vacuum evaporation and coating. Vacuum evaporation mainly uses low-molecular compounds and is a method of forming a thin film on a substrate in a vacuum. It is a practical technology. On the other hand, coating mainly uses high-molecular compounds and is a method of forming a thin film on a substrate using a solution such as inkjet or printing. It has high material utilization efficiency and is suitable for large-area and high-precision displays. It is an indispensable technology for large-area organic EL displays in the future.

The vacuum evaporation method using low molecular weight materials has extremely low material utilization efficiency. If the size is increased, the evaporation mask will bend more, making it difficult to perform uniform evaporation on large substrates. In addition, there is also the problem of increased manufacturing costs.

On the other hand, polymer materials can be applied as a uniform film even on large substrates by applying a solution dissolved in an organic solvent. This phenomenon can be used to apply coating methods represented by inkjet and printing methods. Therefore, the efficiency of material use can be improved, and the manufacturing cost required for device manufacturing can be greatly reduced.

To date, various studies have been conducted on organic EL devices using polymer materials, but there is still a problem that device characteristics such as luminous efficiency and life span may not be sufficient (for example, refer to Patent Documents 1 to 5).

Furthermore, the representative hole transport material that can be used in polymer organic EL devices so far is known to be a fluorene polymer called "TFB" (see Patent Documents 6 to 7). However, since TFB has insufficient hole transport and electron blocking properties, some electrons pass through the light-emitting layer, and the light-emitting efficiency cannot be expected to be improved. In addition, due to the low film adhesion between the adjacent layers, there is also a problem that the device life cannot be expected. [Prior Technical Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Publication No. 2005-272834 [Patent Document 2] Japanese Patent Publication No. 2007-119763 [Patent Document 3] Japanese Patent Publication No. 2007-162009 [Patent Document 4] Japanese Patent Publication No. 2007-177225 [Patent Document 5] International Publication No. 2005/049546 [Patent Document 6] Japanese Patent Publication No. 4375820 [Patent Document 7] International Publication No. 2005/059951

(Invent the problem you want to solve)

The present invention provides: a polymer material having excellent hole injection/transport performance, electron blocking ability, and high stability in a thin film state. Furthermore, the purpose of the present invention is to provide: an organic EL element having an organic layer (thin film) formed by the above polymer material, high luminous efficiency, and long life. (Technical means for solving the problem)

The inventors of the present invention focused on the fact that high molecular weight compounds containing carbazole structural units have high hole injection/transport capabilities and can be expected to have wide energy gaps. They synthesized and examined various high molecular weight triaromatic amine compounds containing carbazole structural units and found that in addition to hole injection/transport capabilities, they also have novel high molecular weight compounds with wide energy gaps, excellent heat resistance and film stability, thereby completing the present invention.

That is, the present invention is described as follows.

[1] A high molecular weight compound comprising at least a carbazole structural unit having a thermally crosslinking group Q represented by the following general formula (1), and having a weight average molecular weight of not less than 10,000 and less than 1,000,000 in terms of polystyrene;

[Chemistry 1] In the above general formula (1), R ₁₁ , R ₁₂ , and R ₁₃ independently represent a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; R ₁₂ and R ₁₃ may be bonded to each other via a single bond, or may have a substituted methylene group, an oxygen atom, or a sulfur atom to form a ring; L ₁ represents a single bond or a divalent aromatic group, and m represents an integer of 1 to 2; and, in the above formula, a11, a12, and b1 are integers as follows: a11 and a12 are 0, 1, 2, or 3; b1=0, 1, 2, 3, or 4.

[2] The high molecular weight compound as described in [1], wherein the thermal crosslinking group Q is a group represented by any one of the following (2a) to (2q);

[Chemistry 2] In the formula, R ₂₁ represents a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; and, in the above formula, a2 and b2 are integers as follows: a2 is 0, 1, 2 or 3; b2 is 0, 1, 2, 3 or 4.

[3] The high molecular weight compound according to [2], comprising: a structural unit represented by the following general formula (3) and a structural unit represented by the following general formula (4);

[Chemistry 3] wherein R ₃₁ and R ₃₃ independently represent a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; R ₃₂ represents an alkyl group, a cycloalkyl group, an alkoxy group, or a cycloalkoxy group having 3 to 40 carbon atoms; L ₃ represents a single bond or a divalent aryl group, and n represents an integer of 1 to 2; and, in the above formula, a3, b31, and b32 are integers as follows: a3 is 0, 1, 2, or 3; b31 and b32 are 0, 1, 2, 3, or 4;

[Chemistry 4] In the formula, R ₄₁ represents a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; X represents a hydrogen atom, an amine group, a monovalent aromatic group, or a monovalent heteroaryl group; and, in the above formula, a4 is an integer as follows: a4 is 0, 1, 2 or 3.

[4] The high molecular weight compound described in [3], which contains a repeating structural unit I represented by the following general formula (5);

[Chemistry 5]

[5] The high molecular weight compound described in [4], further comprising a repeating structural unit II represented by the following general formula (6);

[Chemistry 6]

[6] The high molecular weight compound as described in [5], wherein in the general formulas (1) to (6), a11, a12, a2, a3, a4, b1, b2, b31, and b32 are all 0.

[7] The high molecular weight compound as described in [5], wherein in the general formulas (3) and (5), R ₃₂ is an alkyl group having 3 to 40 carbon atoms.

[8] A high molecular weight compound as described in [7], wherein in the general formulas (4), (5) and (6), X is a hydrogen atom, a diphenylamino group, a phenyl group, a naphthyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a phenanthryl group, a fluorenyl group, a carbazolyl group, an indenocarbazolyl group, or an acridinium group.

[9] An organic electroluminescent device comprising: an organic layer formed using the high molecular weight compound described in any one of [1] to [8].

[10] The organic electroluminescent device described in [9], wherein the organic layer is a hole transport layer.

[11] The organic electroluminescent element as described in [9], wherein the organic layer is an electron blocking layer.

[12] An organic electroluminescent element as described in [9], wherein the organic layer is a hole injection layer. (Compared with the effect of the prior art)

According to the present invention, a high molecular weight compound containing a carbazole structural unit having a thermally crosslinking group Q represented by the above general formula (1) can be provided.

The high molecular weight compound of the present invention is, for example, a polymer having the structural unit as a repeating unit, and preferably has a weight average molecular weight in the range of 10,000 or more and less than 1,000,000 in terms of polystyrene as measured by GPC (gel permeation chromatography).

The high molecular weight compound of the present invention has the following characteristics: (1) good hole injection characteristics, (2) large hole mobility, (3) wide energy gap and excellent electron blocking ability, (4) stable film state, (5) excellent heat resistance.

The organic layer formed by the high molecular weight compound having such physical properties is suitable as the hole transport layer, electron blocking layer, or hole injection layer of the organic EL element. The organic EL element containing the organic layer between a pair of electrodes has the following advantages: (1) high luminous efficiency and electrical efficiency, (2) low practical driving voltage, (3) long life.

That is, according to the present invention, an organic EL element is provided, which is an organic EL element having a pair of electrodes and at least one organic layer sandwiched between the electrodes, wherein the organic layer contains the above-mentioned high molecular weight compound.

<Overview of the invention> The high molecular weight compound of the present invention contains a carbazole structural unit having a thermal crosslinking group Q (hereinafter also referred to as "structural unit A") and has a weight average molecular weight of 10,000 or more and less than 1,000,000 in terms of polystyrene. In particular, the structural unit A of the present invention is characterized in that the thermal crosslinking group Q is bonded to the diaromatic amine skeleton via the carbazole structural bond. The high molecular weight compound of the present invention having such a structural unit A is suitable for a coating method in which a high molecular weight compound dissolved in an organic solvent is insolubilized by a thermal crosslinking reaction to form a film, and has good curability. The organic layer formed by the above-mentioned polymer compound using the coating method has excellent hole injection characteristics, hole mobility, electron blocking ability, film stability, heat resistance and other characteristics, and the organic EL element containing the organic layer can achieve high luminous efficiency and long life. Furthermore, from the perspective of further improving these characteristics and ensuring film forming properties, it is preferred to have a high molecular weight compound (polymer) having a repeating unit composed of the above-mentioned structural unit A and other structural units. From the perspective of improving solubility and ensuring coating properties, other structural units are preferably triaromatic amine structural units (hereinafter also referred to as "structural unit B"), or from the perspective of ensuring the adhesion and durability of the film, it is preferably a connecting structural unit (hereinafter also referred to as "structural unit C"). The following is an explanation of the details.

<Carbazole structural unit, triaromatic amine structural unit and linking structural unit> The carbazole structural unit, triaromatic amine structural unit and linking structural unit possessed by the high molecular weight compound of the present invention are all divalent groups, and are respectively represented by the above general formulas (1), (3) and (4). In addition, in the formula, hydrogen atoms are omitted.

In the general formula (1), _R11 , _R12 , and _R13 independently represent a deuterium atom, a cyano group, a nitro group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom; an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group. The alkyl group, the cycloalkyl group, the alkoxy group, the cycloalkoxy group, the alkenyl group, and the aryloxy group preferably have 1 to 40 carbon atoms.

In said _R11 , _R12 , and _R13 , the carbon number is preferably 1-40 (particularly preferably 3-40), and examples of the alkyl group, alkoxy group, cycloalkyl group, cycloalkoxy group, alkenyl group, and aryloxy group include the following groups: Alkyl group (carbon number 1-40): methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, neohexyl, n-heptyl, isoheptyl, neoheptyl, n-octyl, iso-octyl, neo-octyl, etc.; Alkoxy group (carbon number 1-40): methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, t-butoxy, n-pentoxy, n-hexyl, n-heptyl, n-octyl, etc.; Cycloalkyl group (carbon number 5-40): Cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, etc.; Cycloalkoxy (carbon number 5-40): cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, cyclooctyloxy, 1-adamantyloxy, 2-adamantyloxy, etc.; Alkenyl (carbon number 2-40): vinyl, allyl, isopropenyl, 2-butenyl, etc.; Aryloxy: phenoxy, tolyloxy, etc.

The R ₁₁ , R ₁₂ and R ₁₃ are as described above, but R ₁₁ is preferably a deuterium atom, or an alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, alkenyl group or aryloxy group having 1 to 40 carbon atoms, more preferably a deuterium atom, or an alkyl group, alkoxy group or aryloxy group having 1 to 40 carbon atoms. Furthermore, R ₁₂ and R ₁₃ are preferably a deuterium atom, or an alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, alkenyl group or aryloxy group having 1 to 40 carbon atoms, more preferably a deuterium atom, or an alkyl group, alkoxy group or aryloxy group having 1 to 40 carbon atoms.

R ₁₂ and R ₁₃ may also be bonded to each other via a single bond, or a methylene group, an oxygen atom, or a sulfur atom which may have a substituent to form a ring. For example, when b1 of R ₁₂ is 2, it may be a carbazole derivative such as a benzene ring condensed.

In the above general formula (1), a11, a12, and b1 represent the following integers: a11 and a12 are 0, 1, 2 or 3; b1 is 0, 1, 2, 3 or 4; When a11, a12, and b1 are 0, it means that all the substituents bonded to the ring structures (benzene ring) shown in the general formula (1) are hydrogen atoms. In the high molecular weight compound of the present invention, it is best in terms of synthesis that a11, a12, and b1 are 0, and all the substituents bonded to the ring structures (benzene ring, carbazole ring) shown in the general formula (1) are hydrogen atoms. In addition, it is also preferred that at least one of the substituents bonded to the ring structures shown in the general formula (1) is a deuterium atom. That is, R ₁₁ is a deuterium atom and a11 is 1 to 3, R ₁₂ is a deuterium atom and b1 is 1 to 4, and R ₁₃ is a deuterium atom and a12 is 1 to 3.

The thermal crosslinking group Q possessed by the carbazole structural unit of general formula (1) is a monovalent organic group having a group (typically a alkyl group) that crosslinks by applying heat. In the above-mentioned coating method for forming an organic layer of an organic EL element, the thermal crosslinking group Q suitable for thermal crosslinking reaction can be, for example, a group containing a benzocyclobutene group, an alkenyl group (especially a vinyl group, a butadiene group, a 3,5-hexadiene group), a (meth)acrylate group, etc., preferably a group containing a benzocyclobutene group (benzocyclobutene ring). By using such thermal crosslinking groups Q, the thermal crosslinking rate can be increased. The above-mentioned groups contained in the thermal crosslinking group Q can be directly bonded to the carbazole ring of the general formula (1), and can also be bonded to the carbazole ring via a divalent aromatic group, for example, can be bonded to the carbazole ring via a substituted or unsubstituted phenylene group. Furthermore, the thermal crosslinking group Q is preferably bonded to the 3-position of the carbazole ring. In particular, from the perspective of better curability and longer life of the organic EL element, the thermal crosslinking group Q is more preferably a benzocyclobutene group directly bonded to the 3-position of the carbazole ring. Specific examples of the thermal crosslinking group Q are shown in the above-mentioned general formulas (2a) to (2q).

Furthermore, in the above general formulas (2a) to (2q), the wavy line represents the bonding point with the carbazole structure of general formula (1), and the solid line extending from the ring with a free front end represents that the front end is a methyl group.

In the above general formulae (2a) to (2q), R ₂₁ represents the same groups as R ₁₁ , R ₁₂ , and R ₁₃ shown in the above general formula (1). In the general formulae (2p) and (2q), the R ₂₁ to which the benzene rings are bonded may be the same or different. The R ₂₁ to which the benzene rings are bonded may be bonded to each other via a single bond, a methylene group which may have a substituent, an oxygen atom, or a sulfur atom to form a ring.

In the above general formula (2), a2 and b2 represent the following integers: a2 is 0, 1, 2 or 3; b2 is 0, 1, 2, 3 or 4. When a2 and b2 are 0, it means that all the substituents bonded to the ring structures (benzene rings) shown in the general formula (2) are hydrogen atoms. In the high molecular weight compound of the present invention, it is best in terms of synthesis that a2 and b2 are 0, and all the substituents bonded to the ring structures (benzene rings) shown in the general formulas (2a) to (2q) are hydrogen atoms. In addition, it is also preferred that at least one of the substituents bonded to the ring structures shown in the general formulas (2a) to (2q) is a deuterium atom, that is, it is also preferred that R ₂₁ is a deuterium atom, a2 is 1 to 3, and b2 is 1 to 4.

In the above general formulae (3) and (4), R ₃₁ , R ₃₃ , and R ₄₁ have the same definitions as those of R ₁₁ , R ₁₂ , and R ₁₃ in the above general formula (1). In addition, in the general formula (3), the substituents bonded to each ring structure (benzene ring) may be the same or different. That is, each R ₃₁ and each R ₃₃ may be the same or different. Each R ₃₁ bonded to each benzene ring may be bonded to each other via a single bond, or a methylene group, an oxygen atom, or a sulfur atom which may have a substituent to form a ring. Each R ₃₃ bonded to each benzene ring may be bonded to each other via a single bond, or a methylene group, an oxygen atom, or a sulfur atom which may have a substituent to form a ring.

In the above general formulas (3) to (4), a3, a4, b31, and b32 represent the following integers: a3 and a4 are 0, 1, 2, or 3; b31 and b32 are 0, 1, 2, 3, or 4. When a3, a4, b31, and b32 are 0, it means that all the substituents bonded to the ring structures shown in the general formulas (3) to (4) are hydrogen atoms. In the general formula (3), each b31 may be the same value or different values. In the high molecular weight compound of the present invention, it is best in terms of synthesis that a3, b31, and b32 are 0, and all the substituents bonded to the ring structures (benzene rings) shown in the general formula (3) are hydrogen atoms. In addition, it is also preferred that at least one of the substituents bonded to the ring structures shown in the general formula (3) is a deuterium atom. That is, the case where R ₃₁ is a deuterium atom and b31 is 1 to 4 is also preferred, and the case where R ₃₃ is a deuterium atom, a3 is 1 to 3, and b32 is 1 to 4 is also preferred. Similarly, in the high molecular weight compound of the present invention, it is best in terms of synthesis that a4 is 0 and all the substituents bonded to the ring structures (benzene rings) represented by the general formula (4) are hydrogen atoms. In addition, the case where at least one of the substituents bonded to the ring structures represented by the general formula (4) is a deuterium atom is also preferred, that is, the case where R ₄₁ is a deuterium atom and a4 is 1 to 3 is also preferred.

In the above general formula (3), R ₃₂ represents an alkyl group, a cycloalkyl group, or an alkoxy group having 3 to 40 carbon atoms.

Examples of R ₃₂ include the same groups as those exemplified as the alkyl group, alkoxy group or cycloalkyl group for R ₁₁ , R ₁₂ and R ₁₃ in the general formula (1).

In the high molecular weight compound of the present invention, in order to improve solubility, the above R ₃₂ is preferably an alkyl group having 3 to 40 carbon atoms, and most preferably n-hexyl or n-octyl.

In the above general formula (4), X represents a hydrogen atom, an amino group, a monovalent aromatic group, or a monovalent heteroaryl group.

Examples of monovalent aryl groups and monovalent heteroaryl groups in X include the following groups: Aryl groups; Phenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, indenyl, pyrenyl, peryl, allenylfluorenyl, triphenyl, spirobifluorenyl, etc. Heteroaryl groups; Pyridyl, pyrimidinyl, trioxanyl, furanyl, pyrrolyl, thienyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, indenylcarbazolyl, benzoxazolyl, benzothiazolyl, quinolinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, naphthyridinyl, phenanthrinyl, acridinyl, carbolyl, etc. In X, the example of the amino group is preferably a disubstituted aromatic amino group substituted with the above-mentioned monovalent aromatic group, and the following groups can be exemplified: diphenylamino group (a disubstituted aromatic amino group substituted with a phenyl group), phenylnaphthylamino group (a diarylamino group substituted with a phenyl group and a naphthyl group), phenylfluorenylamino group (a disubstituted amino group substituted with a phenyl group and a fluorenyl group), etc.

Furthermore, the amino group, aryl group, or heteroaryl group may also have a substituent, preferably unsubstituted, or monosubstituted or disubstituted. The substituents include, in addition to deuterium atoms, cyano groups, nitro groups, etc., the following groups can also be listed: Halogen atoms: for example, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms; Alkyl groups, especially those with 1 to 8 carbon atoms: for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, neohexyl, n-heptyl, isoheptyl, neoheptyl, n-octyl, isooctyl, neooctyl; Alkoxy groups, especially those with 1 to 8 carbon atoms: for example, methoxy, ethoxy, propoxy; Alkenyl groups: for example, vinyl, allyl; Aryloxy groups: for example, phenoxy, tolyloxy; Aryl: for example, phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, indenyl, pyrenyl, peryl, allenylfluorenyl, and triphenyl; Heteroaryl: for example, pyridyl, pyrimidinyl, trithionyl, thienyl, furanyl, pyrrolyl, quinolyl, isoquinolyl, benzofuranyl, benzothienyl, indolyl, carbazolyl, indenocarbazolyl, benzoxazolyl, benzothiazolyl, quinolinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothienyl, and carbolyl; Arylvinyl: for example, styryl and naphthylvene; Acyl: for example, acetyl and benzoyl.

Furthermore, the substituents may further have the substituents exemplified above. Furthermore, the substituents are preferably present independently, and the substituents may be bonded to each other via a single bond, or may be bonded to each other via a methylene group, oxygen atom or sulfur atom having a substituent to form a ring.

For example, the above-mentioned aryl group or heteroaryl group may also have a phenyl group as a substituent, and the phenyl group may further have a phenyl group as a substituent. That is, if the aryl group is taken as an example, the aryl group may also be a biphenyl group, a terphenyl group, or a terphenyl group.

In the present invention, specific examples of the substituent X possessed by the linking structural unit C shown in the general formula (4) are shown as substituents 1 to 48 in FIG. 13 and FIG. 14. In the chemical formulas shown in FIG. 13 and FIG. 14, the wavy line represents the bonding position of the linking structural unit C on the benzene ring, and the solid line extending from the ring as a free front end represents that the free front end is a methyl group. The substituent X represents a preferred specific example, but the substituent X used in the present invention is not limited to these substituents.

In the above general formula (4), X is preferably a hydrogen atom, a phenyl group, a biphenyl group, a naphthyl group, a phenanthryl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a fluorenyl group, an indenocarbazolyl group, a diazaindenofluorenyl group, an indenocarbazolyl group, an indolinocarbazolyl group, a diphenyl group, a spirobifluorenyl group, a diphenylamino group (a diarylamino group substituted by a phenyl group), a phenylnaphthylamino group (a diarylamino group substituted by a phenyl group and a naphthyl group), a phenylfluorenylamino group (a disubstituted amino group substituted by a phenyl group and a fluorenyl group), or an acridinyl group. Furthermore, X is more preferably a hydrogen atom, a diphenylamino group, a phenyl group, a naphthyl group, a dibenzofuranyl group, a dibenzothienyl group, a phenanthryl group, a fluorenyl group, a carbazolyl group, an indenocarbazolyl group, or an acridinyl group. Furthermore, X is particularly preferably a hydrogen atom. Furthermore, the amino group, aryl group, or heteroaryl group of X is preferably unsubstituted or substituted with a deuterium atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group, more preferably unsubstituted or substituted with a methyl group, a tert-butyl group, or a phenyl group, and particularly preferably unsubstituted.

In the above general formula (1), _L1 represents a single bond or a divalent aryl group, and m represents an integer of 1 to 2. The aryl group of _L1 is the same as the aryl group exemplified for X. The divalent aryl group of _L1 may be substituted or unsubstituted. _L1 is preferably a single bond or a substituted or unsubstituted phenylene group. When the divalent aryl group has a substituent, it is preferably monosubstituted or disubstituted.

The substituents of the above-mentioned divalent aryl group are the same as the substituents that the above-mentioned X may have, and can be listed as follows: deuterium atom, cyano group, nitro group, halogen atom, alkyl group, alkoxy group, alkenyl group, aryloxy group, aryl group, heteroaryl group, arylvinyl group, or acyl group. The above-mentioned alkyl group, alkoxy group, alkenyl group, aryloxy group, aryl group, heteroaryl group, arylvinyl group, or acyl group may further have a substituent. The divalent aryl group of _L1 is preferably unsubstituted or substituted with an aryl group or an alkyl group having 1 to 8 carbon atoms, more preferably unsubstituted or substituted with a phenyl group, a naphthyl group, a phenanthrenyl group, or a methyl group, and particularly preferably unsubstituted.

In the above general formula (3), L ₃ has the same definition as L ₁ in the general formula (1), and n represents an integer of 1 to 3. The divalent aryl group of L ₃ may be substituted or unsubstituted. L ₃ is preferably a single bond, or a substituted or unsubstituted phenylene group. The divalent aryl group of L ₃ is preferably unsubstituted or substituted with an aryl group or an alkyl group having 1 to 8 carbon atoms, more preferably unsubstituted or substituted with a phenyl group, a naphthyl group, a phenanthrenyl group, or a methyl group, and particularly preferably unsubstituted.

<High molecular weight compound> The high molecular weight compound of the present invention containing the carbazole structural unit represented by the above general formula (1) has a weight average molecular weight in terms of polystyrene measured by GPC of 10,000 or more and less than 1,000,000, more preferably 10,000 or more and less than 500,000, and particularly preferably 10,000 or more and less than 300,000. By setting it within this range, the solubility and viscosity characteristics can be excellent.

Furthermore, the high molecular weight compound of the present invention is preferably a copolymer with other structural units in order to ensure coating properties when forming an organic layer in an organic EL device by coating or to ensure adhesion and durability with other layers. Such other structural units are structural units B shown in general formula (3) for improving solubility or linking structural units C shown in general formula (4). R ₁₁ , R ₃₁ , R ₃₂ , R ₄₁ , Q, L ₁ , L ₃ , a11, a12, a2 to a4, b1, b2, b31 and b32 used in the above general formulas (5) and (6) are the same as those in general formulas (1) to (4).

In the present invention, a preferred embodiment is a high molecular weight compound further containing a repeating structural unit I represented by the general formula (5) composed of structural units B and structural units C together with a structural unit A. In addition, a preferred embodiment is a high molecular weight compound A containing the above-mentioned repeating structural unit I and a repeating structural unit II composed of structural units A and structural units C, or a high molecular weight compound containing a repeating structural unit I and a repeating structural unit III composed of structural units A and structural units B. A high molecular weight compound A containing repeating structural units I and repeating structural units II can be cited as a preferred embodiment, but it is not limited thereto. Furthermore, in the case where the high molecular weight compound having two or more repeating units contains two or more structural units A, B, and C, R ₁₁ , R ₃₁ , R ₃₂ , R ₄₁ , Q, L ₁ , L 3 , a11, a12, a2 to a4, b1, b2, b31, and b32 in each of the general formulae (1), ( ₃ ), and (4) may be different for each repeating unit.

In the high molecular weight compound of the present invention, when the carbazole structural unit represented by the general formula (1) is represented by structural unit A, the triaromatic amine structural unit represented by the general formula (3) is represented by structural unit B, and the linking structural unit represented by the general formula (4) is represented by structural unit C, the structural unit A is preferably contained in an amount of 1 to 20 mol%. Under the condition that the structural unit A is contained in this amount, the structural unit B is preferably contained in an amount of 1 mol% or more, especially 20 to 70 mol%. Furthermore, the structural unit C is preferably contained in an amount of 1 mol% or more, especially 30 to 70 mol%. The high molecular weight compound containing the structural units A, B and C in a manner satisfying these conditions is most suitable for forming an organic layer of an organic EL element.

The high molecular weight compound of the present invention is synthesized by forming a C-C bond or a C-N bond by Suzuki polymerization or Hartwig-Buchwald polymerization, respectively, and then linking each structural unit. That is, a unit compound having each structural unit is prepared, and then the unit compound is appropriately borated or halogenated, and a polycondensation reaction is performed using an appropriate catalyst to synthesize the high molecular weight compound of the present invention.

For example, a copolymer containing 5 mol % of structural unit A represented by general formula (1), 45 mol % of structural unit B represented by general formula (3), and 50 mol % of structural unit C represented by general formula (4) is represented by general formula (7) shown below.

[Chemistry 7]

Among them, it is preferred that the intermediate used for introducing structural unit A and structural unit B is a borate ester, and in contrast, the intermediate used for introducing structural unit C is a halogenated body. Alternatively, it is preferred that the intermediate used for introducing structural unit A and structural unit B is a halogenated body, and in contrast, the intermediate used for introducing structural unit C is a borate ester. That is, it is preferred that the molar ratio of the halogenated body and the borate ester is equal.

The high molecular weight compound of the present invention is dissolved in an aromatic organic solvent such as benzene, toluene, xylene, anisole, etc. to prepare a coating liquid, and then the coating liquid is coated on a predetermined substrate, and by heating and drying, a thin film with excellent properties such as hole injection, hole transport, and electron blocking can be formed. The film also has good heat resistance and good adhesion to other layers.

For example, the high molecular weight compound can be used as a constituent material of a hole injection layer and/or a hole transport layer of an organic EL element. Compared with those formed from conventional materials, the hole injection layer or hole transport layer formed from such a high molecular weight compound has a higher hole injection property, a larger mobility, a higher electron blocking property, can lock the excitons generated in the light-emitting layer, and increase the probability of recombination between holes and electrons, thereby obtaining a high light-emitting efficiency and reducing the driving voltage, thereby achieving the advantage of improving the durability of the organic EL element.

Furthermore, the high molecular weight compound of the present invention having the above-mentioned electrical characteristics has a wider energy gap than conventional materials and is effective in blocking excitons, so it is of course also suitable for use in an electron blocking layer.

<Organic EL element> The organic EL element having an organic layer formed using the high molecular weight compound of the present invention has a structure such as shown in FIG15. That is, on a glass substrate 1 (transparent resin substrate, etc., as long as it is a transparent substrate), there are provided: a transparent anode 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light emitting layer 6, an electron transport layer 7 and a cathode 8.

Of course, the organic EL element to which the high molecular weight compound of the present invention is applied is not limited to the above-mentioned layer structure. A hole blocking layer may be provided between the light-emitting layer 6 and the electron transporting layer 7, and an electron injection layer may be provided between the cathode 8 and the electron transporting layer 7. In addition, some layers may be omitted. For example, a simple layer structure in which an anode 2, a hole transporting layer 4, a light-emitting layer 6, an electron transporting layer 7, and a cathode 8 are provided on a substrate 1 may be used. In addition, a double-layer structure in which layers having the same function are stacked may be used.

The high molecular weight compound of the present invention is suitable for use as a material for forming an organic layer (e.g., hole injection layer 3, hole transport layer 4, or electron blocking layer 5) provided between the anode 2 and the cathode 8 by utilizing its hole injection property or hole transport property.

In the above-mentioned organic EL element, the transparent anode 2 can be formed by a known electrode material itself, and is formed by evaporating ITO or an electrode material with a large work function such as gold on a substrate 1 (a transparent substrate such as a glass substrate).

Furthermore, the hole injection layer 3 provided on the transparent anode 2 can be formed by using a coating liquid in which the high molecular weight compound of the present invention is dissolved in an aromatic organic solvent such as toluene, xylene, anisole, etc. That is, the coating liquid is applied on the transparent anode 2 by spin coating, ink jet, etc., to form the hole injection layer 3.

Furthermore, in an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, the hole injection layer 3 may be formed using a known material, such as the following materials, instead of the high molecular weight compound of the present invention. Porphyrin compounds represented by copper phthalocyanine; Starburst triphenylamine derivatives; Aromatic amines having a structure linked by a single bond or a divalent group containing no impurity atoms (e.g., triphenylamine trimers and tetramers); Acceptor heterocyclic compounds such as hexacyanotriphenylene; Coating-type polymer materials: such as poly(3,4-ethylenedioxythiophene) (PEDOT), poly(styrene sulfonate) (PSS), etc.

When such a material is used to form a layer (thin film), it can be formed by coating using evaporation, spin coating, or inkjet. Similarly, for other layers, the film can be formed by evaporation or coating depending on the type of film-forming material.

The hole transport layer 4 provided on the hole injection layer 3 can be formed by coating the high molecular weight compound of the present invention by spin coating or ink jet coating, similarly to the hole injection layer 3 .

Furthermore, in an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, a hole transporting material known in the art can also be used to form the hole transporting layer 4. Representative examples of such hole transporting materials are as follows: Benzidine derivatives: for example N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (hereinafter referred to as "TPD"), N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine (hereinafter referred to as "NPD"), N,N,N',N'-tetraphenylbenzidine; Amine derivatives: for example 1,1-bis[4-(di-4-toluidine)phenyl]cyclohexane (hereinafter referred to as "TAPC"), various triphenylamine trimers and tetramers; and Coating-type polymer materials can also be used as hole injection layers.

The compound of the hole transport layer includes the high molecular weight compound of the present invention, and can be formed into a film individually or by mixing two or more of them. In addition, one or more of the above compounds can be used to form multiple layers, and the multi-layer film of the layers can be used as the hole transport layer.

15 having an organic layer formed by using the high molecular weight compound of the present invention, the organic EL element may also be provided with a layer having both a hole injection layer 3 and a hole transport layer 4. Such a hole injection/transport layer may also be formed by coating using a polymer material such as PEDOT.

Furthermore, the hole transport layer 4 (hole injection layer 3 as well) may be formed by further using P-doped tris-bromophenylamine hexachloroantiphorate, axylene derivative (for example, see WO2014/009310) or the like with respect to the material commonly used for the layer. In addition, the hole transport layer 4 (or hole injection layer 3) may be formed by using a polymer compound having a TPD basic skeleton or the like.

Furthermore, as shown in FIG. 15 , an electron blocking layer may be provided between the hole transporting layer and the light emitting layer, and may be formed by coating with the high molecular weight compound of the present invention by spin coating or ink jet coating.

Furthermore, in an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, a known electron blocking compound having an electron blocking effect, such as a carbazole derivative, or a compound having a triphenylsilyl group and a triaromatic amine structure, can also be used to form an electron blocking layer. Specific examples of carbazole derivatives and compounds having a triaromatic amine structure are described below. Examples of carbazole derivatives: 4,4',4''-tri(N-carbazolyl)triphenylamine (hereinafter referred to as "TCTA"), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (hereinafter referred to as "mCP"), 2,2-bis(4-carbazol-9-ylphenyl)adamantane (hereinafter referred to as "Ad-Cz"); Examples of compounds having a triaromatic amine structure: 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene.

The electron blocking layer also contains the high molecular weight compound of the present invention, which can be formed into a film alone or by mixing two or more of them. In addition, one or more of the above compounds can be used to form multiple layers, and the multi-layer film thus stacked can be used as the electron blocking layer.

In an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, the light-emitting layer 6 can be formed using various metal complexes such as zinc, curium, and aluminum, as well as light-emitting materials such as anthracene derivatives, bis(vinylbenzene) derivatives, pyrene derivatives, oxadiazole derivatives, and poly(p-styrene ₎ derivatives, in addition to metal complexes of quinolinephenol derivatives headed by Alq 3.

Furthermore, the luminescent layer 6 may also be composed of a main material and a doped material. In this case, the main material may include thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, etc. in addition to the above-mentioned luminescent materials. The doped material may include quinacridone, coumarin, rubrophene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, aminostyryl derivatives, etc.

Such a light-emitting layer 6 may be a single-layer structure using one or more of the light-emitting materials, or may be a multi-layer structure in which a plurality of layers are stacked.

Furthermore, a phosphorescent material may be used as a luminescent material to form the luminescent layer 6. The phosphorescent material may be a phosphorescent material of a metal complex such as iridium or platinum. For example, green phosphorescent materials such as Ir(ppy) ₃ , blue phosphorescent materials such as FIrpic and FIr6, and red phosphorescent materials such as Btp ₂ Ir(acac) may be used. These phosphorescent materials are doped into a hole injection/transport host material or an electron transport host material for use.

In addition, in order to avoid concentration quenching, the phosphorescent light-emitting material is preferably doped into the host material in a range of 1 to 30 weight % relative to the entire light-emitting layer by co-evaporation.

Furthermore, the luminescent material may also include materials that emit delayed fluorescence, such as PIC-TRZ, CC2TA, PXZ-TRZ, 4CzIPN and other CDCB derivatives (see Appl. Phys. Let., 98, 083302 (2011), Chem. Comumm., 48, 11392 (2012), Nature, 492, 234 (2012)).

In an organic EL device having an organic layer formed using the high molecular weight compound of the present invention, a hole injecting/transporting host material may be carbazole derivatives such as 4,4'-di(N-carbazolyl)biphenyl (hereinafter referred to as "CBP"), TCTA, and mCP.

Furthermore, in an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, the electron transporting host material that can be used is: p-bis(triphenylsilyl)benzene (hereinafter referred to as "UGH2"), 2,2',2''-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (hereinafter referred to as "TPBI"), etc.

In an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, the hole blocking layer (not shown in FIG. 9 ) provided between the light-emitting layer 6 and the electron transporting layer 7 can be formed using a compound known to have a hole blocking effect. Examples of such known compounds having a hole blocking effect include the following: Phenanthroline derivatives such as bathocuproin (hereinafter referred to as "BCP"); Metal complexes of quinolinephenol derivatives such as bis(2-methyl-8-quinolinol)-4-phenylphenolaluminum (III) (hereinafter referred to as "BAlq"); Various rare earth complexes; Triazole derivatives; Trioxadiazole derivatives; Oxadiazole derivatives.

These materials can also be used to form the electron transport layer 7 described below, and can also be used as the electron transport layer 7 also serving as a hole blocking layer.

Such a hole blocking layer may also be provided as a single layer or a multi-layered structure, wherein each layer is formed using one or more of the above-mentioned compounds having a hole blocking effect.

In the organic EL element having an organic layer formed using the high molecular weight compound of the present invention, the electron transport layer ₇ can be formed using various metal complexes, pyridine derivatives, pyrimidine derivatives, triazole derivatives, trioxane derivatives, oxadiazole derivatives, thiadiazole derivatives, carbonyldiimide derivatives, quinoline derivatives, phenanthroline derivatives, silole derivatives, benzimidazole derivatives, etc., in addition to the known electron transporting compounds themselves, for example, metal complexes of quinolinephenol derivatives headed by Alq3 and BAlq.

The electron transport layer 7 may be a single layer or a multi-layered structure, and each layer is formed using one or more of the above-mentioned electron transporting compounds.

Furthermore, in an organic EL element having an organic layer formed using the high molecular weight compound of the present invention, the electron injection layer (not shown in FIG. 15 ) provided as required can also be formed using a known substance, for example, an alkali metal salt such as lithium fluoride and cesium fluoride; an alkali earth metal salt such as magnesium fluoride; a metal oxide such as aluminum oxide; an organic metal complex such as lithium quinoline, and the like.

The cathode 8 in the organic EL element having an organic layer formed using the high molecular weight compound of the present invention can use: an electrode material with a low work function such as aluminum; or an alloy with an even lower work function such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-magnesium alloy as the electrode material.

As described above, by using the high molecular weight compound of the present invention to form at least one of the hole injection layer, the hole transport layer, and the electron blocking layer, an organic EL element with high luminous efficiency and power efficiency, low practical driving voltage, low luminous starting voltage, and excellent durability can be obtained. In particular, the organic EL element has high luminous efficiency, reduced driving voltage, improved current tolerance, and increased maximum luminous brightness. [Example]

The present invention is described below using the following experimental examples. In the following description, the carbazole structural unit represented by the general formula (1) of the high molecular weight compound of the present invention is referred to as "structural unit A", the triaromatic amine structural unit represented by the general formula (3) is referred to as "structural unit B", and the linking structural unit represented by the general formula (4) is referred to as "structural unit C".

The synthesized compound was purified by column chromatography and crystallization from a solvent. The compound was identified by NMR analysis.

In order to produce the high molecular weight compound of the present invention, the following intermediates 1 to 4 were synthesized.

<Synthesis of Intermediate 1> [Chemistry 8]

The following components were added to the nitrogen-substituted reaction vessel, and nitrogen was vented for 30 minutes. N,N-bis(4-bromophenyl)-9,9-di-n-octyl-9H-fluoren-2-amine: 16.7 g Bis-pinacol borate: 11.9 g Potassium acetate: 5.7 g 1,4-dioxane: 170 ml Then, 0.19 g of dichloromethane adduct of {1,1'-bis(diphenylphosphino)ferrocene} dichloropalladium(II) was added and heated, and stirred at 100°C for 7 hours. After cooling to room temperature, water and toluene were added, and the organic layer was collected by liquid separation. The organic layer was dehydrated with anhydrous magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was purified using a column chromatography analyzer (ethyl acetate/n-hexane = 1/20) to obtain 7.6 g (yield 40%) of white powder of intermediate 1.

<Synthesis of Intermediate 2> [Chemistry 9]

The following components were added to the nitrogen-substituted reaction vessel, and nitrogen was ventilated for 30 minutes. 3-(4,4,5,5-tetramethyl-1,3,2-diborane-2-yl)carbazole: 5.3 g 4-bromobenzocyclobutene: 3.5 g Potassium carbonate: 3.4 g Water: 10 ml 1,4-dioxane: 30 ml Then, 0.4 g of tetrakis(triphenylphosphine)palladium was added and heated, and stirred at 84°C for 3 hours. After cooling to room temperature, water and toluene were added, and the organic layer was collected by liquid separation. The organic layer was dehydrated with anhydrous magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was recrystallized with toluene to obtain 3.5 g (yield 71%) of slightly white powder of intermediate 2.

<Synthesis of Intermediate 3> [Chemical 10]

The following components were added to a nitrogen-substituted reaction vessel and stirred at 110°C for 5 hours. Intermediate 2: 3.5 g 1,3-Dibromo-5-fluorobenzene: 6.6 g Csium carbonate: 6.3 g Dimethyl sulfoxide: 28 ml After cooling to room temperature, methanol was added and filtered to obtain a crude product. The crude product was recrystallized with ethyl acetate to obtain 4.1 g of slightly white powder of intermediate 3 (yield 63%).

<Synthesis of Intermediate 4> [Chemical 11]

Add the following components to the nitrogen-substituted reaction vessel and ventilate with nitrogen for 30 minutes. Intermediate 3: 4.1 g Bis-pinacol borate: 4.3 g Potassium acetate: 2.4 g 1,4-Dioxane: 30 ml Next, add 67 mg of dichloromethane adduct of {1,1'-bis(diphenylphosphino)ferrocene}palladium dichloride (II) and heat, stirring at 90°C for 5 hours. After cooling to room temperature, add water and toluene, and perform liquid separation to collect the organic layer. The organic layer is dehydrated with anhydrous magnesium sulfate and concentrated under reduced pressure to obtain a crude product. The crude product was crystallized using toluene/methanol = 1/1 to obtain 1.9 g (yield 38%) of white powder of intermediate 4. [Example 1]

<Synthesis of high molecular weight compound A> Add the following components to the nitrogen-substituted reaction vessel and ventilate with nitrogen for 30 minutes. Intermediate 1 (equivalent to structural unit B): 5.4g 1,3-dibromobenzene (equivalent to structural unit C): 1.7g Intermediate 4 (equivalent to structural unit A): 0.4g Tripotassium phosphate: 7.4g Toluene: 9ml Water: 5ml 1,4-Dioxane: 27ml

Next, add 1.5 mg of palladium acetate (II) and 12.4 mg of tri-ortho-tolylphosphine, heat, and stir at 87°C for 6 hours. Then, add 19 mg of phenylboric acid, stir for 2 hours, and then add 262 mg of bromobenzene, stir for 2 hours. Add 50 ml of toluene and 50 ml of a 5 wt% sodium N,N-diethyldithiocarbamate aqueous solution, heat, and stir under reflux for 2 hours. After cooling to room temperature, perform a liquid separation operation to collect an organic layer, and wash it three times with saturated saline. After dehydrating the organic layer with anhydrous sodium sulfate, concentrate it under reduced pressure to obtain a crude polymer. The crude polymer was dissolved in toluene, silica gel was added for adsorption purification, and the silica gel was removed by filtration. The obtained filtrate was concentrated under reduced pressure, 100 ml of toluene was added to the dried solid and dissolved, and the mixture was dropped into 300 ml of n-hexane, and the obtained precipitate was filtered. This operation was repeated 3 times and dried to obtain high molecular weight compound A: 3.4 g (yield 72%).

The average molecular weight and dispersion of high molecular weight compound A measured by GPC are as follows. Number average molecular weight Mn (polystyrene conversion): 69,000 Weight average molecular weight Mw (polystyrene conversion): 124,000 Dispersion (Mw/Mn): 1.8

Furthermore, NMR measurement was performed on the high molecular weight compound A. The ¹ H-NMR measurement results are shown in FIG16 . The chemical composition formula is as follows. [Chemical 12]

From the above chemical composition, it can be understood that the polymer compound A contains 5 mol% of the structural unit A represented by the general formula (1), 45 mol% of the structural unit B represented by the general formula (3), and 50 mol% of the linking structural unit C represented by the general formula (4). [Example 2]

<Synthesis of high molecular weight compound B> Add the following components to the nitrogen-substituted reaction vessel and ventilate with nitrogen for 30 minutes. Intermediate 1 (equivalent to structural unit B): 5.4g 1,3-dibromobenzene (equivalent to structural unit C): 1.4g Intermediate 3 (equivalent to structural unit A): 0.3g Tripotassium phosphate: 7.4g Toluene: 9ml Water: 5ml 1,4-Dioxane: 27ml

Next, 1.5 mg of palladium acetate (II) and 12.4 mg of tri-ortho-tolylphosphine were added, heated, and stirred at 89°C for 7 hours. Then, 19 mg of phenylboric acid was added, stirred for 2 hours, and then 262 mg of bromobenzene was added, stirred for 2 hours. 50 ml of toluene and 50 ml of a 5 wt% sodium N,N-diethyldithiocarbamate aqueous solution were added, heated, and stirred under reflux for 2 hours. After cooling to room temperature, the organic layer was collected by liquid separation and washed three times with saturated saline. The organic layer was dehydrated with anhydrous sodium sulfate and concentrated under reduced pressure to obtain a crude polymer. The crude polymer was dissolved in toluene, silica gel was added for adsorption purification, and the silica gel was removed by filtration. The obtained filtrate was concentrated under reduced pressure, 100 ml of toluene was added to the dried solid and dissolved, and the mixture was dripped into 300 ml of n-hexane, and the obtained precipitate was filtered. This operation was repeated 3 times and dried to obtain high molecular weight compound B: 3.3 g (yield 71%).

The average molecular weight and dispersion of high molecular weight compound B measured by GPC are as follows. Number average molecular weight Mn (polystyrene conversion): 88,000 Weight average molecular weight Mw (polystyrene conversion): 158,000 Dispersion (Mw/Mn): 1.8

Furthermore, NMR measurement was performed on the high molecular weight compound B. The ¹ H-NMR measurement results are shown in FIG17 . The chemical composition formula is as follows. [Chemical 13]

From the above chemical composition, it can be understood that the polymer compound B contains 5 mol% of the structural unit A represented by the general formula (1), 50 mol% of the structural unit B represented by the general formula (3), and 45 mol% of the linking structural unit C represented by the general formula (4). [Example 3]

Using the high molecular weight compounds A and B synthesized in Examples 1 and 2, a coating film with a thickness of 80 nm was prepared on an ITO substrate, and the work function was measured using an ionization potential measuring device (manufactured by Sumitomo Heavy Industries, Ltd., PYS-202 model). The results are as follows. Work function High molecular weight compound A (polymer)                  5.62eV High molecular weight compound B (polymer)                  5.60eV

Compared with the work function of 5.4eV of general hole transport materials such as NPD and TPD, the high molecular weight compounds A and B of the present invention exhibit a better energy level and are known to have good hole transport capabilities. [Example 4]

<Production of organic EL elements> The organic EL element with the layer structure shown in Figure 15 was produced according to the following method.

Specifically, a glass substrate 1 on which a 50 nm thick ITO film is formed is cleaned with an organic solvent, and then the ITO surface is cleaned with UV/ozone treatment. In a manner that covers a transparent anode 2 (ITO) provided on the glass substrate 1, a PEDOT/PSS (manufactured by Ossila) film is formed with a thickness of 50 nm by spin coating, and dried on a hot plate at 200° C. for 10 minutes to form a hole injection layer 3.

A high molecular weight compound (HTM-1) of the following structural formula was dissolved in toluene at 0.4 wt% to prepare a coating solution. The substrate on which the hole injection layer 3 was formed in the above manner was moved into a hand-operated work box substituted with dry nitrogen, and dried on a hot plate at 230°C for 10 minutes. Then, a coating layer with a thickness of 15 nm was formed on the hole injection layer 3 using the above coating solution and a spin coating method, and then dried on a hot plate at 220°C for 30 minutes to form a hole transport layer 4.

[Chemistry 14]

The high molecular weight compound A obtained in Example 1 was dissolved in toluene at 0.4 wt% to prepare a coating solution. On the hole transport layer 4 formed in the above manner, a coating layer with a thickness of 15 nm was formed by spin coating using the coating solution, and then dried on a hot plate at 220° C. for 30 minutes to form an electron blocking layer 5.

The substrate on which the electron blocking layer 5 was formed in the above manner was placed in a vacuum evaporator and the pressure was reduced to below 0.001 Pa. On the electron blocking layer 5, a luminescent layer 6 with a film thickness of 34 nm was formed by binary evaporation of a blue luminescent material (EMD-1) and a host material (EMH-1). In addition, during binary evaporation, the evaporation rate ratio was set to EMD-1:EMH-1=4:96.

[Chemistry 15]

The electron transport material used was the compound (ETM-1) and (ETM-2) having the following structural formula.

[Chemistry 16]

On the light-emitting layer 6 formed above, an electron transport layer 7 with a film thickness of 20 nm is formed by binary evaporation using the electron transport materials (ETM-1) and (ETM-2). In addition, during binary evaporation, the evaporation rate ratio is set to ETM-1:ETM-2=50:50.

Finally, aluminum is evaporated to a film thickness of 100 nm to form a cathode 8. In this way, the glass substrate formed with a transparent anode 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a luminescent layer 6, an electron transport layer 7 and a cathode 8 is moved into a hand-operated box substituted with dry nitrogen, and another glass substrate for sealing is bonded with a UV curing resin to form an organic EL element. The characteristics of the organic EL element produced are measured in the atmosphere at room temperature. In addition, the luminescence characteristics when a DC voltage is applied to the organic EL element produced are measured. The above measurement results are shown in Table 1. [Example 5]

An organic EL device was produced in exactly the same manner as in Example 4, except that a coating solution prepared by dissolving the high molecular weight compound B obtained in Example 2 in toluene at 0.4 wt % was used instead of the high molecular weight compound A to form the electron blocking layer 5. Various characteristics of the produced organic EL device were evaluated in the same manner as in Example 4, and the results are shown in Table 1.

[Comparative Example 1] An organic EL element was prepared in exactly the same manner as in Example 4 except that a coating solution prepared by dissolving TFB (hole transporting polymer) at 0.4 wt% in toluene was used instead of high molecular weight compound A to form electron blocking layer 5. .

[Chemistry 17]

TFB (hole transporting polymer) is poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-tert-butylphenyl))diphenylamine] (manufactured by American Dye Source, Hole Transport Polymer ADS259BE). The various properties of the organic EL element of Comparative Example 1 were evaluated in the same manner as in Example 4. The results are shown in Table 1.

In the evaluation of various characteristics, the voltage, luminance, luminous efficiency and power efficiency are the values when a current density of 10 mA/cm ² is flowing. In addition, the device life is the time from when the luminous luminance at the beginning of luminescence (initial luminance) is set to 700 cd/m ² and a constant current is applied, and the luminous luminance decays to 560 cd/m ² (equivalent to 80% of the initial luminance set to 100%: 80% decay) is measured.

[Table 1] Electron blocking layer Voltage [V] Brightness [cd/m ² ] Luminous efficiency [cd/A] Power efficiency [lm/W] Component life 80% attenuation Embodiment 4 High molecular weight compound A 4.07 665 6.64 5.13 648 hours Embodiment 5 High molecular weight compound B 4.13 707 7.07 5.37 491 hours Comparison Example 1 TFB 4.02 550 5.05 4.29 11 hours

As shown in Table 1, the luminous efficiency of the organic EL element of Comparative Example 1 when a current density of 10 mA/cm ² is flowing is 5.05 cd/A, while that of the organic EL element of Example 4 is 6.64 cd/A and that of Example 5 is 7.07 cd/A, both showing high efficiency. Furthermore, in terms of element life (80% attenuation), the organic EL element of Comparative Example 1 is 11 hours, while that of the organic EL element of Example 4 is 648 hours and that of the organic EL element of Example 5 is 491 hours, both showing long life. In particular, the high molecular weight compound A composed of repeating structural units I and II has a longer life than the high molecular weight compound B composed of repeating structural units I and III. (Industrial Applicability)

The high molecular weight compound of the present invention is excellent as a compound for a coating type organic EL element due to its high hole transporting ability and excellent electron blocking ability. By using the compound to make a coating type organic EL element, high luminous efficiency and electric efficiency can be obtained, and durability can be improved. For example, the application can be expanded to household electrical products or lighting.

1: Glass substrate 2: Transparent anode 3: Hole injection layer 4: Hole transport layer 5: Electron blocking layer 6: Luminescent layer 7: Electron transport layer 8: Cathode

Figure 1 is the chemical structure of structural units 5-1 to 5-6, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 2 is the chemical structure of structural units 5-7 to 5-12, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 3 is the chemical structure of structural units 5-13 to 5-18, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 4 is the chemical structure of structural units 5-19 to 5-24, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 5 is the chemical structure of structural units 5-25 to 5-30, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 6 is the chemical structure of structural units 5-31 to 5-36, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 7 is the chemical structure of structural units 5-37 to 5-42, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 8 is the chemical structure of structural units 5-43 to 5-48, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 9 is the chemical structure of structural units 5-49 to 5-54, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. Figure 10 is the chemical structure of structural units 5-55 to 5-60, which are preferably exemplified examples of the repeating structural unit represented by the general formula (5) of the present invention. FIG. 11 shows the chemical structures of structural units 5-61 to 5-66, which are preferred examples of the repeating structural unit represented by the general formula (5) of the present invention. FIG. 12 shows the chemical structures of structural units 5-67 to 5-72, which are preferred examples of the repeating structural unit represented by the general formula (5) of the present invention. FIG. 13 shows the chemical structures of substituents 1 to 24, which are preferred examples of the substituent X of the general formula (4), the general formula (5) and the general formula (6) of the present invention. FIG. 14 shows the chemical structures of substituents 25 to 48, which are preferred examples of the substituent X of the general formula (4), the general formula (5) and the general formula (6) of the present invention. FIG. 15 shows an example of the layer structure of the organic EL element of the present invention. Fig. 16 is a ¹ H-NMR chart of the high molecular weight compound (Compound A) obtained in Example 1 of the present invention. Fig. 17 is a ¹ H-NMR chart of the high molecular weight compound (Compound B) obtained in Example 2 of the present invention.

Claims (12)

A high molecular weight compound comprising at least a carbazole structural unit having a thermal crosslinking group Q represented by the following general formula (1) and having a weight average molecular weight of 10,000 or more and less than 1,000,000 in terms of polystyrene; [Chemical 1] In the above general formula (1), R ₁₁ , R ₁₂ , and R ₁₃ independently represent a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; R ₁₂ and R ₁₃ may be bonded to each other via a single bond, or may have a substituted methylene group, an oxygen atom, or a sulfur atom to form a ring; L ₁ represents a single bond or a divalent aromatic group, and m represents an integer of 1 to 2; and, in the above formula, a11, a12, and b1 are the following integers: a11 and a12 are 0, 1, 2, or 3; b1=0, 1, 2, 3, or 4. The high molecular weight compound of claim 1, wherein the thermal crosslinking group Q is a group represented by any one of the following (2a) to (2q); [Chemical 2] In the formula, R ₂₁ represents a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; and, in the above formula, a2 and b2 are integers as follows: a2 is 0, 1, 2 or 3; b2 is 0, 1, 2, 3 or 4. The high molecular weight compound of claim 2 comprises: a structural unit represented by the following general formula (3) and a structural unit represented by the following general formula (4); [Chemical 3] wherein R ₃₁ and R ₃₃ independently represent a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; R ₃₂ represents an alkyl group, a cycloalkyl group, or an alkoxy group having 3 to 40 carbon atoms; L ₃ represents a single bond or a divalent aryl group, and n represents an integer of 1 to 2; and, in the above formula, a3, b31, and b32 are integers as follows: a3 is 0, 1, 2, or 3; b31 and b32 are 0, 1, 2, 3, or 4; [Chemistry 4] In the formula, R ₄₁ represents a deuterium atom, a cyano group, a nitro group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkenyl group, or an aryloxy group; X represents a hydrogen atom, an amine group, a monovalent aromatic group, or a monovalent heteroaryl group; and, in the above formula, a4 is an integer as follows: a4 is 0, 1, 2 or 3. The high molecular weight compound of claim 3 contains a repeating structural unit I represented by the following general formula (5): . The high molecular weight compound of claim 4 further comprises a repeating structural unit II represented by the following general formula (6): . A high molecular weight compound as claimed in claim 5, wherein in the above general formulas (1) to (6), a11, a12, a2, a3, a4, b1, b2, b31, and b32 are all 0. The high molecular weight compound of claim 5, wherein in the above general formulas (3) and (5), R ₃₂ is an alkyl group having 3 to 40 carbon atoms. A high molecular weight compound as claimed in claim 7, wherein in the general formulas (4), (5) and (6), X is a hydrogen atom, a diphenylamino group, a phenyl group, a naphthyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, an indenocarbazolyl group, or an acridinium group. An organic electroluminescent device comprises: an organic layer formed using the high molecular weight compound of any one of claims 1 to 8. The organic electroluminescent device of claim 9, wherein the organic layer is a hole transport layer. The organic electroluminescent element of claim 9, wherein the organic layer is an electron blocking layer. The organic electroluminescent device of claim 9, wherein the organic layer is a hole injection layer.