CN113889581A

CN113889581A - Organic electroluminescent element

Info

Publication number: CN113889581A
Application number: CN202010625162.XA
Authority: CN
Inventors: 叶子勤; 孙霞; 王仁宗
Original assignee: Chan N Changzhou Tronly Eray Optoelectroincs Material Co ltd
Current assignee: Changzhou Tronly New Electronic Materials Co Ltd
Priority date: 2020-07-01
Filing date: 2020-07-01
Publication date: 2022-01-04

Abstract

The present invention provides an organic electroluminescence element. The organic electroluminescence element includes a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer stacked in sequence, and the host of the light-emitting layer includes compound A or compound B,

The electron transport layer includes compound C:

The compound C in the electron transport layer of the organic electroluminescence element has the same fragment as the compound A and compound B in the main body of the light-emitting layer, so the interface effect between the film layers is weakened, which is conducive to the rapid transfer of electrons to the light-emitting layer; due to the luminescence The host material of the layer has bipolar characteristics, which further balances the transport capacity of holes and electrons. Therefore, the synergistic effect of the above-mentioned substances is integrated, so that the efficiency of the organic electroluminescence element is significantly improved.

Description

Organic electroluminescent element

Technical Field

The invention relates to the technical field of electroluminescence, in particular to an organic electroluminescence element.

Background

The organic electroluminescent element has characteristics of lightness, thinness, wide viewing angle, high contrast, low power consumption, high response speed, full-color picture, flexibility and the like, and is currently applied to the fields of smart phones, tablet computers, vehicles and the like, and is expanded to large-size application fields of forward televisions and the like.

The organic electroluminescent element generally comprises a hole injection layer, a hole transport layer, an electron blocking layer, a luminescent layer, a hole blocking layer, an electron transport layer, an electron injection layer and other film layers, wherein holes and electrons are respectively injected from an anode and a cathode and enter the luminescent layer through the transport layer to be mutually compounded to emit light, the efficiency of the element depends on the recombination probability of the holes and the electrons, and therefore, the regulation and control of the balance of carriers at two ends is critical. The main means for regulation and control are as follows: the injection and transmission of holes and electrons are improved, and the recombination probability of the holes and the electrons is further improved; the blocking property of holes and electrons is improved, and the generated excitons are limited in the light-emitting layer to obtain high light-emitting efficiency; or the fragments with electron activity and the fragments with hole activity are combined to form the bipolar host material, so that electrons and holes can be simultaneously transmitted, the electrons and the holes are balanced, exciton quenching is reduced, and the luminous efficiency is improved.

The molecular structure of the bipolar host material is generally complex, and many factors need to be considered, so that a good bipolar material can be obtained by simply combining a fragment having electron activity and a fragment having hole activity, and the balance of electron and hole transport capacities and the stability of the material need to be considered. And the material selection on both sides of the device is matched with the device, so that the aim of optimizing the performance of the device can be fulfilled.

Disclosure of Invention

The invention mainly aims to provide an organic electroluminescent element to solve the problem that the luminous efficiency of a device is low due to the fact that holes and electrons of the electroluminescent element in the prior art are difficult to balance.

In order to achieve the above object, according to one aspect of the present invention, there is provided an organic electroluminescent element comprising a hole injection layer, a hole transport layer, a light emitting layer and an electron transport layer stacked in this order, the host of the light emitting layer comprising compound a or compound B,

the electron transport layer comprises compound C:

further, the hole injection layer includes any one or more arylamine compounds and any one or more axine derivatives doped therein,

the arylamine compounds have the general formula I:

wherein Ar is₁To Ar₄Each independently represents substituted or unsubstituted C₆-C₃₀Aryl, substituted or unsubstituted C₅-C₃₀Heteroaryl group, Ar₁And Ar₂Two, Ar₃And Ar₄The substituents on both may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom or a sulfur atom to form a ring, and n is any one integer of 0 to 4;

the axine derivative has the general formula II:

wherein Ar is₆Is C substituted by an electron-withdrawing group₆-C₁₈Preferably the electron withdrawing group is fluorine or cyano.

Further, in the above general formula I, Ar₁To Ar₄Each independently selected from any one of substituted or unsubstituted phenyl, biphenyl, naphthyl, fluorenyl, phenyl or carbazolyl.

Further, in the above general formula II, Ar₆Selected from phenyl or biphenyl groups substituted with at least one cyano or F atom.

Further, in the arylamine compound and the squalene derivative, the amount ratio of doped substance of the limonene derivative is 2% to 20%.

Further, the above hole transport layer includes a first hole transport layer and a second hole transport layer stacked in this order away from the hole injection layer, and the first hole transport layer includes any one or more arylamine compounds.

Further, the above-mentioned second hole transport layer includes any one or more triarylamine compounds represented by general formula III:

wherein Ar is₇、Ar₈And Ar₉Each independently represents substituted or unsubstituted C₆-C₃₀Aryl, substituted or unsubstituted C₅-C₃₀Any one of heteroaryl groups.

Further, in the above formula III, Ar₇、Ar₈And Ar₉Each independently selected from any one of biphenyl group, fluorenyl group, dibenzofuranyl group, phenyl substituted naphthyl group, phenyl substituted dibenzofuranyl group or phenyl substituted carbazolyl group.

Further, the guest of the light-emitting layer is any one or more phosphorescent red dyes represented by the general formula IV:

wherein R is₁、R₂、R₃、R₄Each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl, substituted or unsubstituted C₆-C₃₀Aryl, or substituted or unsubstituted C₅-C₃₀A heteroaryl group; m and n are each independently any integer of 0 to 4.

Further, in the above formula IV, R₁、R₂、R₃、R₄Each independently selected from any one of methyl, ethyl, isopropyl, isobutyl or 3-methylpentyl, and m is preferably1 or 2, n is preferably 1 or 2.

By applying the technical scheme of the invention, the compound C in the electron transport layer of the organic electroluminescent element has the same segment as the compound A and the compound B in the main body of the light-emitting layer, so that the interface effect between the film layers is weakened, and the rapid transmission of electrons to the light-emitting layer is facilitated; in addition, the host material of the luminescent layer has bipolar property, so that the transport capacity of holes and electrons is further balanced, and the efficiency of the organic electroluminescent element is obviously improved by combining the mutual synergistic action of the substances.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a schematic structural diagram of an OLED cell provided in accordance with an embodiment of the present invention;

the figures include the following reference numerals:

1. an anode layer; 2. a hole injection layer; 3. a first hole transport layer; 4. a second hole transport layer; 5. a light emitting layer; 6. an electron transport layer; 7. an electron injection layer; 8. a cathode layer.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

As analyzed in the background of the present application, in the prior art, although it is theoretically possible to combine a fragment having electron activity and a fragment having hole activity to form a bipolar host material, it is possible to simultaneously transport electrons and holes, balance them, reduce exciton quenching, and thereby improve luminous efficiency. However, in practice, depending on the application environment and the like, it is not always possible to improve the light emission efficiency of any bipolar host material having the above characteristics. In view of the above, the present application provides an organic electroluminescent element comprising a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer stacked in this order, the host of the light-emitting layer comprising compound a or compound B,

the electron transport layer comprises compound C:

the compound C in the electron transport layer of the organic electroluminescent element has the same segment as the compound A and the compound B in the main body of the luminescent layer, so that the interface effect between the film layers is weakened, and the rapid transport of electrons to the luminescent layer is facilitated; in addition, the host material of the luminescent layer has bipolar property, so that the transport capacity of holes and electrons is further balanced, and the efficiency of the organic electroluminescent element is obviously improved by combining the mutual synergistic action of the substances.

In one embodiment of the present application, in order to reduce the interface effect between the hole injection layer and the hole transport layer, it is preferable that the hole injection layer includes any one or more arylamine compounds and any one or more axine derivatives doped therein,

the arylamine compounds have the general formula I:

the axine derivative has the general formula II:

The aromatic amino compound is used as a main body of the hole injection layer, so that the low interface effect between the hole injection layer and the hole transport layer is ensured, meanwhile, the axiene derivative is doped, the electron-withdrawing capability of the axiene derivative is utilized, the injection and transport capability of holes to the light-emitting layer is improved, and the recombination probability of the holes and electrons is improved.

In a preferred embodiment, in formula I, Ar is₁To Ar₄Each independently selected from any one of substituted or unsubstituted phenyl, biphenyl, naphthyl, fluorenyl, phenyl or carbazolyl. Further, it is preferable that the above arylamine compound is selected from any one or more of the following compounds:

preferably, in the above formula II, Ar₆Selected from phenyl or biphenyl groups substituted with at least one cyano or F atom. Further, the above-mentioned axiene derivative may be selected from any one or more of the following compounds:

in order to achieve a balance between the interface effect and the electron transport ability to obtain a more desirable light emission efficiency, it is preferable that the ratio of the amount of the dopant of the limonene derivative to the amount of the dopant of the limonene derivative is 2% to 20%, and it is more preferable that the ratio of the amount of the dopant of the limonene derivative is 2% to 8%.

In one embodiment of the present application, the hole transport layer includes a first hole transport layer and a second hole transport layer stacked sequentially away from the hole injection layer, and the first hole transport layer includes an arylamine compound. Since both the first hole transport layer and the hole injection layer have an arylamine compound, the interface effect between the two layers is weak, and in order to further reduce the interface effect, it is preferable that the arylamine compounds of the two layers are the same.

In one embodiment, the second hole transport layer comprises any one or more triarylamine compounds represented by formula III:

wherein Ar is₇、Ar₈And Ar₉Each independently represents substituted or unsubstituted C₆-C₃₀Aryl, substituted or unsubstituted C₅-C₃₀Any one of heteroaryl groups. The triarylamine compound makes the second hole transport layer assist the further transport of holes on the one hand and can confine electrons in the light emitting layer to improve the light emitting efficiency on the other hand.

Further, in the above formula III, Ar is preferably Ar₇、Ar₈And Ar₉Each independently selected from any one of biphenyl group, fluorenyl group, dibenzofuranyl group, phenyl substituted naphthyl group, phenyl substituted dibenzofuranyl group or phenyl substituted carbazolyl group. Preferably, the triarylamine compound may be selected from any one or more of the following compounds:

in order to further improve the luminous efficiency and stability, the guest of the light-emitting layer is preferably any one or more phosphorescent red dyes represented by formula IV:

wherein R is₁、R₂、R₃、R₄Each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl, substituted or unsubstituted C₆-C₃₀Aryl, or substituted or unsubstituted C₅-C₃₀A heteroaryl group; m and n are each independently any integer of 0 to 4. The phosphorescent red dye with the structure is matched with a main material in the luminescent layer, so that a better electron and hole recombination effect can be realized.

Preferably, in the above formula IV, R₁、R₂、R₃、R₄Each independently selected from any one of methyl, ethyl, isopropyl, isobutyl or 3-methylpentyl, m is preferably 1 or 2, and n is preferably 1 or 2. Further, it is preferable that the phosphorescent red dye is selected from any one or more of the following compounds:

the advantageous effects of the present application will be further described below with reference to examples and comparative examples.

Synthetic examples

1.1 Synthesis of intermediate M1

2, 4-dichloroquinoline (29.7g,150mmol), 3-phenylcarbazole (36.9g,157.5mmol) and toluene (500mL) were added to a 1L four-necked flask, and after stirring and oxygen removal by introduction of nitrogen for 15 minutes, the mixture was heated to 50 ℃ to dissolve the solids, and after the solids were cleared, dipalladium tris (dibenzylideneacetone) (2.05g,2.25mmol) and 1,1' -bis (diphenylphosphino) ferrocene (4.98g,9mmol) were added to the four-necked flask, and after 15 minutes of reaction, sodium tert-butoxide (21.6g,225mmol) was further added to the four-necked flask, followed by heating to 110 ℃ and refluxing for 5 hours. After the reaction was completed, the reaction mixture was cooled to room temperature, and filtered through silica gel pad, and the solvent in the filtrate was evaporated in vacuo to obtain a crude product containing intermediate M1, which was recrystallized from a tetrahydrofuran-ethanol mixed solvent to obtain 48g of intermediate M1, which was a white-like solid powder of intermediate M1 at a yield of 79%. The purity is 98.5%.

1.2 Synthesis of Compound A

Intermediate M1(20g,49.4mmol), pinacol diboron (18.8g,74.1mmol), potassium acetate (9.8g,99mmol), 1, 4-dioxane (200mL) were charged into a 500mL four-necked flask, stirred and deoxygenated with nitrogen for 15 minutes, heated to 50 ℃ and incubated for 15 minutes, palladium acetate (350mg,1.49mmol) and tricyclohexylphosphine fluoroborate (1.1g,3mmol) were added to the four-necked flask, and then heated to 100 ℃ and refluxed for 4 hours. After completion of the reaction, the pad silica gel was filtered while hot, and the obtained filtrate was subjected to vacuum evaporation of the solvent therefrom to obtain a crude product containing intermediate M2, which was recrystallized from ethanol to obtain 16.13g of intermediate M2, which was M2 as a pale yellow solid powder with a yield of 65%. The purity is 95.4%.

Intermediate M2(4.96g,10mmol), 2-chloro-4, 6-diphenyl-1, 3, 5-triazine (2.94g,11mmol), ethylene glycol dimethyl ether (50mL), and an aqueous potassium carbonate solution (1M,20mL,20mmol) were added to a 250mL four-necked flask, stirring was started, nitrogen was introduced to remove oxygen for 15 minutes, the mixture was heated to 50 ℃ for reaction for 15 minutes, and then tetrakis (triphenylphosphine) palladium (350mg,1.49mmol) was added to the four-necked flask, and the mixture was heated to 85 ℃ for reflux for 4 hours. After the reaction is completed, the temperature is reduced to room temperature and the mixture is filtered to obtain a crude product containing the compound A, the crude product is subjected to soxhlet extraction by tetrahydrofuran and then filtered, and the obtained filter cake is washed by a tetrahydrofuran-ethanol mixed solvent (1: 4) to obtain 3.4g of the compound A which is orange solid powder with the yield of 56.5 percent. The purity is 97.5%. The compound a was further purified twice by vacuum sublimation with a purity of 99.97%.

The structural characterization results for compound a are as follows:

¹H NMR(400MHz,CDC1₃)δ9.16(d,J＝8.2Hz,1H),8.79(d,J＝8.1Hz,SH),8.36(s,2H),8.21(dd,J＝16.2,8.2Hz,3H),7.99-7.84(m,1H),7.76(d,J＝7.4Hz,4H),7.70-7.4S(m,9H),7.40(dd,J＝13.8,7.0Hz,2H).

1.3 Synthesis of Compound B

Intermediate M1(4.04g,10mmol), 2, 3-dimethylquinoxaline-6-boronic acid pinacol ester (3.12g,11mmol), ethylene glycol dimethyl ether (50mL), and an aqueous potassium carbonate solution (1M,20mL,20mmol) were added to a 250mL four-necked flask, stirred and purged with nitrogen to remove oxygen for 15 minutes, and then heated to 50 ℃ for 15 minutes, and after reaction, tetrakis (triphenylphosphine) palladium (350mg,1.49mmol) was added to the four-necked flask and heated to 85 ℃ for 4 hours under reflux. After the reaction was completed, the pad silica gel was filtered while it was hot, and the solvent was distilled off from the obtained filtrate in vacuo to obtain a crude product containing compound B, which was recrystallized from ethanol to obtain 4.52g of compound B as pale yellow solid powder with a yield of 86%. The purity is 99.3%. Compound B was further purified twice by vacuum sublimation with a purity of 99.98%.

The structural characterization results for compound B are as follows:

¹H NMR(400MHz,CDCl₃)δ8.32(dd,J＝22.8,4.7Hz,3H),8.25-8.08(m,4H),8.01(d,J＝8.3Hz,1H),7.97-7.88(m,2H),7.88-7.80(m,1H),7.74(d,J＝8.1Hz,3H),7.57(t,J＝7.2Hz,1H),7.50(dd,J＝14.7,7.2Hz,3H),7.37(q,J＝7.2Hz,2H),2.81(d,J＝4.2Hz,6H).

synthesis of Compound C

In a 500mL three-necked flask, 4-bromoo-phenylenediamine (20g,0.106mol), 2, 3-butanedione (9.66g,0.112mol) and toluene (200mL) were added, and the mixture was refluxed for 3 hours. After the reaction is finished, cooling to room temperature, filtering with silica gel pad, evaporating the solvent in the obtained filtrate in vacuum to obtain a crude product, dissolving the crude product with n-hexane for decoloration and recrystallization to obtain 18.0g of an intermediate M3, wherein the intermediate M3 is off-white solid powder, and the yield is 71%. The purity is 99.95%.

In a three-necked flask, intermediate M3(10g,0.042mol), 2- [3- (4,4,5, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl) phenyl ] -4, 6-diphenyl-1, 3, 5-triazine (18.36g,0.042mol), potassium carbonate (11.65g,0.084mol), tetrakis- (triphenylphosphine) palladium (0.49g), toluene (150ml), ethanol (45ml) and water (30ml) were charged, and heated under nitrogen atmosphere to reflux for 8 hours. After the reaction is finished, cooling to room temperature, extracting with toluene and water, filtering the organic layer pad silica gel, evaporating the solvent in the obtained filtrate in vacuum to obtain a crude product, dissolving the crude product with toluene, decoloring and recrystallizing to obtain 13.3g of a compound C, wherein the compound C is white solid powder, the yield is 68%, and the purity is 99.93%. The compound C is purified by vacuum sublimation for 2 times, and the purity is 99.96%.

The structural characterization results for compound C are as follows:

1H NMR(400MHz,CDCl₃)δ9.13(s,1H),8.83-8.79(m,5H),8.36(d,J＝1.6Hz,1H),8.14-8.07(m,2H),7.97(d,J＝8Hz,1H),7.71(t,J＝7.8Hz,1H),7.63-7.57(m,6H),2.79(d,J＝2.8Hz,6H).

2. performance characterization

The physicochemical properties of the compound A, the compound B and the compound C are characterized, the absorption wavelength of the material is measured by using an Shimadzu UV-2600 type ultraviolet spectrophotometer, the solvent is THF, the material concentration is about 10ppm, and the material concentration is measured to be E_g＝1240/UV_onset(ii) a Then, a Vertex.C.EIS type electrochemical workstation is utilized, a glassy carbon electrode is used as a working electrode, a saturated calomel electrode-saturated potassium chloride solution is used as a reference electrode, a platinum wire electrode is used as a counter electrode, and dichloromethane 50% + acetonitrile 50% (material concentration is about 5 multiplied by 10) is used as a solvent^-4mol/L), 0.1M tetrabutylammonium hexafluorophosphate as an electrolyte, ferrocene as a standard substance, starting measurement after nitrogen is introduced for 10 minutes at normal temperature, measuring the oxidation-reduction potential of the material under the scanning condition of the speed of 0.1V/s, and finally converting the oxidation-reduction potential into LUMO and HOMO energy poles. The characterization results are shown in table 1.

TABLE 1

3. Preparation of organic electroluminescent element

Practical effects of the organic electroluminescent device prepared by the material combination used in the present invention are explained in detail by specific examples and comparative examples below.

Device example 1

Referring to the structure shown in fig. 1, the method for manufacturing the OLED device by using a Sunic sp1710 evaporator comprises the following specific steps: a glass substrate (corning glass 40mm x 0.7mm) coated with ITO (indium tin oxide, as anode layer 1) having a thickness of 135nm was ultrasonically washed with isopropyl alcohol and pure water for 5 minutes, then cleaned with ultraviolet ozone, and then transferred to a vacuum deposition chamber; compound 1-1 and compound 2-2 were mixed (compound 2-2 was mixed at a ratio of 4%) and vacuum-coated on a transparent ITO electrode (about 10%^-7Torr) thermal deposition to a thickness of 20nm to form a hole injection layer 2; compound 1-1 was then vacuum deposited on the hole injection layer to a thickness of 60nm as a first hole transport layer 3; then, vacuum deposition is carried out on the compound 3-3 with the thickness of 10nm to form a second hole transport layer 4; then, a 25nm compound A with the doping mass fraction of 4% of the compound 4-1 is deposited in vacuum to be used as a light-emitting layer 5; then, depositing a compound C doped with 50% LiQ (8-hydroxyquinoline lithium) in vacuum to form an electron transport layer 6 with the thickness of 30 nm; finally depositing metal ytterbium (Yb) with the thickness of 2nm as an electron injection layer 7 and magnesium-silver alloy with the doping ratio of 10:1 in sequence to form a cathode layer 8; the components were finally transferred from the deposition chamber into a glove box, which was then encapsulated with a UV curable epoxy resin and a glass cover plate containing a moisture absorber.

In the above manufacturing steps, the deposition rates of the organic material, ytterbium metal and Mg metal were maintained at 0.1nm/s, 0.05nm/s and 0.2nm/s, respectively.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-2(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A: 4% compound 4-1(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 2

An experiment was performed in the same manner as in example 1 except that: compound 1-3 was used in place of compound 1-1, compound 2-4 was used in place of compound 2-2, compound 3-6 was used in place of compound 3-3, and compound 4-4 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-3: 4% compound 2-4(20 nm)/compound 1-3(60 nm)/compound 3-6(10 nm)/compound A: 4% compound 4-4(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 3

An experiment was performed in the same manner as in example 1 except that: instead of Compound 1-1, Compound 1-8 was used, Compound 2-6 was used instead of Compound 2-2, Compound 3-8 was used instead of Compound 3-3, and Compound 4-6 was used instead of Compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-8: 4% compound 2-6(20 nm)/compound 1-8(60 nm)/compound 3-8(10 nm)/compound A: 4% compound 4-6(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 4

An experiment was performed in the same manner as in example 1 except that: compounds 1-10 were used in place of compound 1-1, compound 2-8 was used in place of compound 2-2, compound 3-12 was used in place of compound 3-3, and compound 4-10 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-10: 4% compound 2-8(20 nm)/compound 1-10(60 nm)/compound 3-12(10 nm)/compound A: 4% compound 4-10(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 5

An experiment was performed in the same manner as in example 1 except that: compound 2-7 was used in place of compound 2-2, and compound 4-6 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-7(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A: 4% compound 4-6(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 6

An experiment was performed in the same manner as in example 1 except that: compound 2-9 was used in place of compound 2-2, and compound 4-12 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-9(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A: 4% compound 4-12(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 7

An experiment was performed in the same manner as in example 1 except that: compound B was used instead of compound a.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-2(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound B: 4% compound 4-1(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 8

An experiment was performed in the same manner as in example 1 except that: compound B was used in place of compound A, compound 1-3 was used in place of compound 1-1, compound 2-4 was used in place of compound 2-2, and compound 4-4 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-3: 4% compound 2-4(20 nm)/compound 1-3(60 nm)/compound 3-3(10 nm)/compound B: 4% compound 4-4(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 9

An experiment was performed in the same manner as in example 1 except that: compound B was used in place of compound A, compound 1-8 was used in place of compound 1-1, compound 2-6 was used in place of compound 2-2, and compound 4-6 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-8: 4% compound 2-6(20 nm)/compound 1-8(60 nm)/compound 3-3(10 nm)/compound B: 4% compound 4-6(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 10

An experiment was performed in the same manner as in example 1 except that: compound B was used in place of compound A, compound 1-10 was used in place of compound 1-1, compound 2-8 was used in place of compound 2-2, and compound 4-10 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-10: 4% compound 2-8(20 nm)/compound 1-10(60 nm)/compound 3-3(10 nm)/compound B4% compound 4-10(25 nm)/compound C LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 11

An experiment was performed in the same manner as in example 1 except that: compound B was used in place of compound A, compound 2-7 was used in place of compound 2-2, and compound 4-6 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-7(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound B: 4% compound 4-6(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 12

An experiment was performed in the same manner as in example 1 except that: compound B was used in place of compound A, compound 2-9 was used in place of compound 2-2, and compound 4-12 was used in place of compound 4-1.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-9(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound B: 4% compound 4-12(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 13

An experiment was performed in the same manner as in example 1 except that the impurity doping amount ratio of the compound 2-2 was 2% when the hole injection layer was formed.

The element structure is represented as: ITO (135 nm)/compound 1-1: 2% compound 2-2(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A: 4% compound 4-1(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 14

An experiment was performed in the same manner as in example 1, except that the doping content ratio of compound 2-2 was 6% when the hole injection layer was formed.

The element structure is represented as: ITO (135 nm)/compound 1-1: 6% compound 2-2(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A: 4% compound 4-1(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 15

An experiment was performed in the same manner as in example 1, except that the doping content ratio of compound 2-2 was 8% when the hole injection layer was formed.

The element structure is represented as: ITO (135 nm)/compound 1-1: 8% compound 2-2(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A: 4% compound 4-1(25 nm)/compound C: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Device example 16

An experiment was performed in the same manner as in example 1 except that compound 2-2 was not used in forming the hole injection layer.

The element structure is represented as: ITO (135 nm)/compound 1-1(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A4% compound 4-1(25 nm)/compound C LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Comparative device example 1

An experiment was performed in the same manner as in example 1 except that: compound 2-7 was used in place of compound 2-2, compound 4-6 was used in place of compound 4-1, and compound ETA was used in place of compound C.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-7(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound A: 4% compound 4-6(25nm)/ETA: LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

Comparative device example 2

An experiment was performed in the same manner as in device comparative example 1 except that: compound B was used instead of compound a.

The element structure is represented as: ITO (135 nm)/compound 1-1: 4% compound 2-7(20 nm)/compound 1-1(60 nm)/compound 3-3(10 nm)/compound B4% compound 4-6(25nm)/ETA LiQ (5:5,30nm)/Yb (2nm)/Mg: Ag (10:1,150 nm).

The luminance of the element, the luminous efficiency, the EQE (external quantum efficiency) were measured by the sfs-100 GA4 test, french, all in a room temperature atmosphere. The element is at 10mA/cm²Specific performance data for operating voltage (V), current efficiency (C.E.), External Quantum Efficiency (EQE), and color coordinates (CIEx, CIEy) at current density are shown in table 2.

TABLE 2

As can be seen from the table, the above-described embodiments of the present invention achieve the following technical effects: device efficiencies of device examples 1 to 6 were improved as compared with device comparative example 1, and similarly, device efficiencies of device examples 7 to 12 were further improved as compared with device comparative example 2, and the improvement was more remarkable as compared with the device using compound a as a host. This is because the difference in LUMO energy levels of both compounds B and C is smaller (0.03eV), while the difference in LUMO energy levels of both compounds a and C is 0.41eV, so electrons are more easily injected into the light-emitting layer in device example 2, and thus are more easily combined with holes, further improving the light-emitting efficiency.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. an organic electroluminescence element, the organic electroluminescence element comprises a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer stacked in sequence, wherein the main body of the light-emitting layer comprises Compound A or Compound B,

The electron transport layer includes Compound C:

2 . The organic electroluminescent element according to claim 1 , wherein the hole injection layer comprises any one or more arylamine compounds and any one or more alkenes doped therein. 3 . derivative,

The arylamine compound has the general formula I:

Wherein, Ar ₁ to Ar ₄ each independently represent a substituted or unsubstituted C ₆ -C ₃₀ aryl group, a substituted or unsubstituted C ₅ -C ₃₀ heteroaryl group, and both the Ar ₁ and the Ar ₂ , the substituents on both the Ar ₃ and the Ar ₄ can be combined with each other to form a ring via a single bond, a substituted or unsubstituted methylene group, an oxygen atom or a sulfur atom, and n is any integer from 0 to 4;

The alkene derivatives have the general formula II:

Wherein, Ar ₆ is an aryl group containing C ₆ -C ₁₈ substituted with an electron withdrawing group, preferably the electron withdrawing group is a fluorine or a cyano group.

3. The organic electroluminescence element according to claim 2, wherein in the general formula I, the Ar ₁ to the Ar ₄ are each independently selected from substituted or unsubstituted phenyl, biphenyl any one of phenyl, naphthyl, fluorenyl, phenyl or carbazolyl.

4. The organic electroluminescence element according to claim 2 or 3, characterized in that, in the general _formula II, the Ar is selected from phenyl or biphenyl substituted with at least one cyano group or F atom .

5. The organic electroluminescence element according to any one of claims 2 to 4, wherein among the plurality of arylamine compounds and the alkene derivatives, the alkene derivatives are doped with The impurity ratio is 2% to 20%.

6. The organic electroluminescent element according to claim 2 or 3, wherein the hole transport layer comprises a first hole transport layer and a second hole transport layer which are stacked away from the hole injection layer in sequence layer, the first hole transport layer includes any one or more of the arylamine compounds.

7. The organic electroluminescence element according to claim 6, wherein the second hole transport layer comprises any one or more triarylamine compounds represented by the general formula III:

Wherein, Ar ₇ , Ar ₈ and Ar ₉ each independently represent any one of a substituted or unsubstituted C ₆ -C ₃₀ aryl group and a substituted or unsubstituted C ₅ -C ₃₀ heteroaryl group.

8 . The organic electroluminescence element according to claim 5 , wherein, in the general formula III, the Ar ₇ , the Ar ₈ and the Ar ₉ are each independently selected from biphenyl, fluorene any of phenyl, dibenzofuranyl, phenyl-substituted naphthyl, phenyl-substituted dibenzofuryl, or phenyl-substituted carbazolyl.

9. The organic electroluminescent element according to claim 1, wherein the guest of the light-emitting layer is any one or more phosphorescent red dyes represented by the general formula IV:

Wherein, R ₁ , R ₂ , R ₃ , and R ₄ are each independently selected from substituted or unsubstituted C ₁ -C ₁₀ alkyl, substituted or unsubstituted C ₆ -C ₃₀ aryl, or substituted or unsubstituted C 6 -C 30 aryl C ₅ -C ₃₀ heteroaryl;

m and n are each independently any integer from 0 to 4.

10 . The organic electroluminescence element according to claim 9 , wherein, in the general formula IV, the R ₁ , the R ₂ , the R ₃ , and the R ₄ are each independently selected from the group consisting of 10 . Any of methyl, ethyl, isopropyl, isobutyl or 3-methylpentyl, m is preferably 1 or 2, and n is preferably 1 or 2.