An organic compound with a furan-containing mother nucleus and application thereof

Abstract

The application provides an organic compound with a furan structure as a mother nucleus and an application thereof, and belongs to the technical field of semiconductor materials.The organic compound has a structure shown in general formula 1.The organic compound can be used as an NCGL material, thereby reducing the driving voltage of an OLED, improving the light-emitting efficiency of the OLED, and prolonging the service life of the OLED.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor materials, and relates to an organic compound with furan structure as a parent core and application thereof. BACKGROUND

[0002] Organic electroluminescence (OLED: Organic Light Emission Diodes) device technology can be used to manufacture new display products and new lighting products, and is expected to replace existing liquid crystal display and fluorescent lamp lighting, and has a very wide application prospect. The OLED light-emitting device has a sandwich structure, including an electrode material film layer and organic functional materials sandwiched between different electrode film layers, and various different functional materials are stacked together according to the use to jointly constitute the OLED light-emitting device. As a current device, when a voltage is applied to the two electrodes of the OLED light-emitting device, and the positive and negative charges in the organic layer functional material film layer are acted on by the electric field, the positive and negative charges are further recombined in the light-emitting layer, that is, OLED electroluminescence is generated.

[0003] In a stacked OLED, the stacked OLED is a series connection of two or more independent light emitting units through a charge generation layer (CGL). Under the action of an applied electric field, electrons and holes generated by the CGL are injected into adjacent light emitting units and recombine into excitons to emit light. Therefore, the material selection and design of the CGL are key factors affecting the optical and electrical performance and the lifetime of the stacked OLED. The CGL layer is constructed in the form of a P-N structure, in which the P-type material mainly generates holes, such as F4-TCNQ and HAT-CN materials, and the N-type doped material is a low work function metal doped with an electron transport layer material, such as Alq3:Mg and Bphen:Li. Therefore, the performance of the electron transport material of the N-type doped material in the CGL has a very large influence on the performance of the device, and it is required to have high efficiency of electron injection, transport and high durability of electrons. At the same time, the heat resistance and film stability of the material are also important. Materials with low heat resistance not only decompose easily during material evaporation, but also decompose thermally during device operation and cause material degradation. In the case of poor film phase stability of the material, the material also crystallizes in the form of a thin film in a short period of time, resulting in direct separation of the organic film layer and causing device degradation. Therefore, it is required to use a material with high heat resistance and good film stability. OLED has developed a variety of structures, among which a series connection type OLED with a plurality of light reflection layers stacked has been developed. The series connection type OLED has the following structure: a plurality of stacks each formed of a hole injection layer (HIL) / a hole transport layer (HTL) / a light emitting layer / an electron transport layer (ETL) / an electron injection layer (EIL) are stacked between an anode electrode and a cathode electrode. In particular, a charge generation layer (CGL) formed of an NCGL (N-type charge generation layer) and a PCGL (P-type charge generation layer) is provided between the stacks to generate charges or inject charges into the light emitting layer.

[0004] However, in the CGL, the property of injecting electrons generated at the interface between the PCGL and the adjacent hole injection layer into the NCGL through charge generation between the NCGL and the PCGL is insufficient. In addition, when a conventional NCGL is doped with an alkali metal, the alkali metal diffuses into the PCGL, resulting in a decrease in the lifetime of the OLED.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide an organic compound with a furan-containing mother nucleus and its application. The organic compound of the present application can be used as an NCGL material, thereby reducing the driving voltage of the OLED, improving the light emitting efficiency of the OLED, and prolonging the device lifetime of the OLED.

[0007] To achieve the object of the present application, the present application adopts the following technical solutions:

[0008] In one aspect, the present application provides an organic compound with furan structure as a mother nucleus, the organic compound has a structure shown in general formula 1:

[0009]

[0010] X1-X8, same or different from each other, are each independently selected from N or CR, and at least one of which is an N atom, and the rest are CR;

[0011] R is selected from hydrogen, deuterium, a substituted or unsubstituted C6-C 24 aryl, a substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S;

[0012] A, B, same or different from each other, are each independently selected from hydrogen, deuterium, phenyl, naphthyl, bi-phenyl, tri-phenyl or phenanthryl; A, B are connected to the ring group where they are located by a single bond or fused with the ring group connected thereto;

[0013] L is selected from a substituted or unsubstituted C6-C 24 aryl, a substituted or unsubstituted C6-C 24 heteroaryl, wherein the heteroatom is selected from O, N or S;

[0014] R1 is selected from hydrogen, deuterium, a substituted or unsubstituted C6-C 24 aryl, a substituted or unsubstituted C6-C 24 heteroaryl, wherein the heteroatom is selected from O, N or S;

[0015] Ar is selected from a substituted or unsubstituted C6-C 24 aryl, a substituted or unsubstituted C6-C 24 heteroaryl, wherein the heteroatom is selected from O, N or S;

[0016] All hydrogens in general formula 1 are unsubstituted by deuterium, partially substituted by deuterium or completely substituted by deuterium.

[0017] Preferably, when A, B are connected to the ring group where they are located by a single bond, the substitution number of A, B is mono-substitution, di-substitution, tri-substitution or tetra-substitution.

[0018] Preferably, when A, B are fused with the ring group connected thereto, the fusion mode is that A is fused with the bond where X1, X2 are located or X2, X3 are located or X3, X4 are located, and B is fused with the bond where X5, X6 are located or X6, X7 are located or X7, X8 are located.

[0019] Further preferably, L is selected from substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl or substituted or unsubstituted naphthyl.

[0020] Further preferably, R is selected from hydrogen, deuterium, phenyl, biphenyl, terphenyl or naphthyl.

[0021] Further preferably, R1is selected from hydrogen, deuterium, phenyl, biphenyl, terphenyl, naphthyl or pyridyl.

[0022] Further preferably, Ar is selected from phenyl, biphenyl, terphenyl, naphthyl or pyridyl.

[0023] The above "substitution" is mono-substitution or poly-substitution, and the substituted groups (e.g. the substituted C6-C 24 C6-C 24 The substituents in the aryl, substituted C6-C 10 alkyl, C6-C 24 aryl, C6-C 24 heteroaryl, wherein the heteroatom is selected from O, N or S.

[0024] In the above technical solution, further preferably, the organic compound containing furan structure is any one of the following structures, but is not limited thereto:

[0025] ;

[0026] ;

[0027] ;

[0028] ;

[0029] ;

[0030] ;

[0031] ;

[0032] ;

[0033] ;

[0034] ;

[0035] ;

[0036] ;

[0037] ;

[0038] ;

[0039] ;

[0040] ;

[0041] ;

[0042] ;

[0043] ;

[0044] ;

[0045] ;

[0046] .

[0047] The method for preparing the organic compound of the present application is as follows:

[0048]

[0049] wherein Hal1, Hal2 are selected from halogen.

[0050] The starting material A (1.0 eq) and the starting material B (1.0-1.1 eq) are put into a mixture of toluene, ethanol, and water under nitrogen protection, then the gas is exchanged 3 times, potassium carbonate (2.0 eq-2.5 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq-0.015 eq) are added under nitrogen protection, stirred uniformly, heated to 90-100°C, refluxed for 8-10 h, the reaction is completed, the temperature is slightly lowered, diatomite is used for filtration to remove the salt and catalyst, the filtrate is cooled to room temperature, washed with water 3 times, the organic phase is reserved, then the water phase is extracted with ethyl acetate; the organic phases are combined, dried with anhydrous magnesium sulfate, and the solvent is removed with a rotary evaporator to obtain the intermediate 1.

[0051] Under nitrogen protection, intermediate 1 (1.0 eq) and raw material C (1.0-1.1 eq) are uniformly stirred in a mixed solvent of 280 mL of toluene, ethanol and water (volume ratio of 2:1:1), then X-Phos (2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 0.05 eq-1.0 eq), palladium acetate (Pd(OAc)2) (0.05 eq-1.0 eq), cesium carbonate (2.0 eq-2.5 eq) are added, the mixture is stirred thoroughly, then heated to 90-100°C and stirred for 8-10 h, after the reaction is completed, the temperature is slightly lowered, diatomite is used for filtration to remove the salt and catalyst, the filtrate is cooled to room temperature, washed with water for three times, the organic phase is reserved, then the water phase is extracted with ethyl acetate; the organic phases are combined, dried with anhydrous magnesium sulfate, and the solvent is removed by using a rotary evaporator to obtain a compound represented by general formula 1.

[0052] In another aspect, the present application provides an organic electroluminescence device, which comprises an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, and the organic thin film layer comprises the organic compound as described above.

[0053] Preferably, the organic thin film layer comprises a charge generation layer, and the material of the charge generation layer comprises the organic compound as described above.

[0054] Preferably, the charge generation layer comprises an N-type charge generation layer and a P-type charge generation layer, and the material of the N-type charge generation layer comprises the organic compound as described above.

[0055] Preferably, the organic thin film layer further comprises any one or a combination of at least two of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer or an electron transport layer.

[0056] Compared with the prior art, the present application has the following beneficial effects:

[0057] The compound provided by the present application takes furan structure as a mother nucleus structure, and contains unsaturated nitrogen atoms in the mother nucleus, so that the compound has suitable LUMO and HOMO energy levels, high charge generation capacity and high electron transport performance, can effectively improve the light emitting efficiency of the organic electroluminescence device, reduce the driving voltage of the device, and prolong the service life of the organic electroluminescence device. The compound of the present application can effectively inhibit the film crystallinity of the molecule, improve the film stability and heat resistance of the material, and is beneficial to improve the efficiency and service life of the device.

[0058] After the compound of the present application is applied to the OLED device as an organic electroluminescence NCGL layer material, the driving voltage of the device can be effectively reduced, and the light emitting efficiency and service life of the device can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the compound 2 prepared in Example 1 was measured. DETAILED DESCRIPTION

[0060] The technical solutions of the present application are further illustrated by the specific embodiments. It should be understood by those skilled in the art that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0061] Example 1

[0062] The starting material C was synthesized by the following preparation method

[0063]

[0064] Under the protection of nitrogen, the starting material C-1 (1.0 eq) and the starting material C-2 (1.0 eq) were put into a DMF solution, K2CO3 (2.0 eq) was added under the protection of nitrogen, and stirred uniformly, and then heated to 150°C, and refluxed for 8h. After the reaction was completed, the reaction liquid was introduced into ice water after being cooled to room temperature, and a solid was precipitated to obtain the target product intermediate C-1.

[0065] Under the protection of nitrogen, the intermediate C-1 (1.0 eq) and the starting material C-3 (1.1 eq) were stirred uniformly in a mixed solvent of 280 mL of toluene, ethanol and water (volume ratio 2:1:1), and then X-Phos (0.05 eq), palladium acetate (Pd(OAc)2) (0.05 eq) and cesium carbonate (2.0 eq) were added. After stirring sufficiently, the temperature was increased to 90°C and stirred for 10h. After the reaction was completed, the temperature was slightly lowered, and diatomite was used for filtration to remove the salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water for three times, and the organic phase was retained. Then, the water phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent to obtain the starting material C (yield: 52.6%).

[0066]

[0067] Under the protection of nitrogen, the starting material A (1.0 eq) and the starting material B (1.0 eq) were put into a mixed solution of toluene, ethanol and water (volume ratio = 2:1:1), and then the gas was exchanged for 3 times. Potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under the protection of nitrogen, and stirred uniformly. The temperature was increased to 90°C, and refluxed for 8h. After the reaction was completed, the temperature was slightly lowered, and diatomite was used for filtration to remove the salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water for three times, and the organic phase was retained. Then, the water phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent to obtain the intermediate 1.

[0068] The intermediate 1 (1.0 eq) and the raw material C (1.1 eq) were stirred in a mixed solvent of 280 mL of toluene, ethanol and water (volume ratio of 2:1:1) under nitrogen protection, then X-Phos (0.05 eq), palladium acetate (Pd(OAc)2) (0.05 eq), cesium carbonate (2.0 eq) were added, the reaction was stirred at 90°C for 10 h after being heated to 90°C, the temperature was slightly lowered after the reaction was completed, diatomite was used for filtration to remove the salt and catalyst, the filtrate was cooled to room temperature, washed with water three times, the organic phase was reserved, then the water phase was extracted with ethyl acetate; the organic phase was combined, dried with anhydrous magnesium sulfate, and the solvent was removed by using a rotary evaporator to obtain compound 2 (yield: 70.2%).

[0069] The obtained compound 2 was detected and analyzed, and the results were as follows:

[0070] HPLC purity: >99.95%.

[0071] MS (ESI, m / Z): [M+H] + : 551.19

[0072] Elemental analysis:

[0073] Calculated value: C, 82.89; H, 4.03; N, 10.18; O, 2.91.

[0074] Test value: C, 82.75; H, 4.42; N, 10.34; O, 3.18.

[0075] The nuclear magnetic hydrogen spectrum of compound 2 is shown in Figure 1 .

[0076] Example 2

[0077] The raw material C needs to be synthesized by the following preparation method

[0078]

[0079] The raw material C-1 (1.0 eq) and the raw material C-2 (1.0 eq) were put into a DMF solution under nitrogen protection, K2CO3 (2.0 eq) was added under nitrogen protection, stirred uniformly, heated to 150°C, refluxed for 8 h, after the reaction was completed, the reaction liquid was introduced into ice water, and a solid was precipitated to obtain the target product intermediate C-1.

[0080] Under nitrogen protection, intermediate C-1 (1.0 eq) and raw material C-3 (1.1 eq) were stirred in a mixed solvent of 280 mL of toluene, ethanol and water (volume ratio 2:1:1), then X-Phos (0.05 eq), palladium acetate (Pd(OAc)2) (0.05 eq), cesium carbonate (2.0 eq) were added, stirred fully, then heated to 90°C and stirred for 10 h. After the reaction was completed, the temperature was slightly lowered, diatomite was used for filtration, the salt and catalyst were removed, the filtrate was cooled to room temperature, washed with water three times, the organic phase was reserved, then the aqueous phase was extracted with ethyl acetate; the organic phases were combined, dried with anhydrous magnesium sulfate, and the solvent was removed by using a rotary evaporator to obtain raw material C (yield: 53.1%).

[0081]

[0082] Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.1 eq) were put into a mixed solution of toluene, ethanol and water (volume ratio = 2:1:1), then the gas was exchanged three times, potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under nitrogen protection, stirred fully, heated to 90°C, refluxed for 8 h, the reaction was completed, the temperature was slightly lowered, diatomite was used for filtration, the salt and catalyst were removed, the filtrate was cooled to room temperature, washed with water three times, the organic phase was reserved, then the aqueous phase was extracted with ethyl acetate; the organic phases were combined, dried with anhydrous magnesium sulfate, and the solvent was removed by using a rotary evaporator to obtain intermediate 1.

[0083] Under nitrogen protection, intermediate 1 (1.0 eq) and raw material C (1.1 eq) were stirred in a mixed solvent of 280 mL of toluene, ethanol and water (volume ratio 2:1:1), then X-Phos (0.05 eq), palladium acetate (Pd(OAc)2) (0.05 eq), cesium carbonate (2.0 eq) were added, stirred fully, then heated to 90°C and stirred for 10 h. After the reaction was completed, the temperature was slightly lowered, diatomite was used for filtration, the salt and catalyst were removed, the filtrate was cooled to room temperature, washed with water three times, the organic phase was reserved, then the aqueous phase was extracted with ethyl acetate; the organic phases were combined, dried with anhydrous magnesium sulfate, and the solvent was removed by using a rotary evaporator to obtain compound 160 (yield: 68.2%).

[0084] The obtained compound 160 was detected and analyzed, and the results were as follows:

[0085] HPLC purity: >99.95%.

[0086] MS (ESI, m / Z): [M+H] + : 577.21

[0087] Elemental analysis:

[0088] Calculated values: C, 83.31; H, 4.20; N, 9.72; O, 2.77.

[0089] Analytical values: C, 83.12; H, 4.58; N, 10.09; O, 2.98.

[0090] The synthesis methods of other compounds are the same as those in the above examples and are not described in detail here.

[0091] Device Application Example 1: Preparation of Organic Electroluminescent Devices

[0092] Anode: ITO anode: A 150nm thick ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice in distilled water, ultrasonically cleaned for 30 minutes, then rinsed twice in distilled water, ultrasonically cleaned for 10 minutes, and then baked in a vacuum oven at 220°C for 2 hours. After baking, the substrate was cooled and ready for use. This substrate served as the anode and was deposited using an evaporation device. Other functional layers were then deposited on top.

[0093] First hole injection layer: On the washed anode layer, HT-1 and P-1 were deposited with a thickness of 10 nm using a vacuum evaporation device. The mass ratio of HT-1 to P-1 was 97:3 as the first hole injection layer.

[0094] First hole transport layer: On the first hole injection layer, HT-1 was evaporated to a thickness of 24 nm as the first hole transport layer.

[0095] First electron blocking layer: EB-1 was then evaporated on the first hole transport layer to a thickness of 5 nm as the first electron blocking layer.

[0096] First light-emitting layer: After the above-mentioned first electron blocking material is evaporated, the light-emitting layer of the OLED light-emitting device is prepared. Its structure includes the OLED light-emitting layer using BH-1 as the main material and BD-1 as the doping material. The doping ratio of the doping material is 3% by weight, and the light-emitting layer film thickness is 20nm.

[0097] First hole blocking layer: After the first light-emitting layer, 5 nm of HB-1 was evaporated as the first hole blocking layer;

[0098] First electron transport layer: After the first hole blocking layer, 10 nm of ETM-1 and Liq were vacuum evaporated, with the mass ratio of ETM-1:Liq being 1:1 as the first electron transport layer.

[0099] NCGL layer: On the first electron transport layer, an N-type charge generation layer (NCGL layer) was deposited by a vacuum evaporation device, in which the mass ratio of compound 2:Yb was 95:5, and the film thickness was 20 nm.

[0100] PCGL layer: On the NCGL layer, a co-evaporated layer of HT-1 and P-1 with a film thickness of 10 nm was deposited by a vacuum evaporation device, and the mass ratio of HT-1 and P-1 was 95:5 as the P-CGL layer.

[0101] Second hole transport layer: Then, HT-1 with a film thickness of 30 nm was evaporated as the second hole transport layer.

[0102] Second electron blocking layer: Subsequently, EB-1 with a thickness of 5 nm was evaporated on the above-mentioned second hole transport layer as the second electron blocking layer.

[0103] Second light-emitting layer: After the evaporation of the above-mentioned second electron blocking material was completed, the second light-emitting layer of the OLED light-emitting device was prepared, and the structure included that BH-1 was used as the host material and BD-1 was used as the dopant material in the OLED second light-emitting layer, the doping ratio of the dopant material was 3% by weight, and the film thickness of the light-emitting layer was 20 nm.

[0104] Second hole blocking layer: After the above-mentioned second light-emitting layer, 5 nm of HB-1 was continuously evaporated by a vacuum evaporation device, and this layer was the second hole blocking layer.

[0105] Second electron transport layer: On the second hole blocking layer, 15 nm of ETM-1 and Liq were evaporated as the second electron transport layer, and the mass ratio of ETM-1: Liq was 1:1.

[0106] Second electron injection layer: On the second electron transport layer, 1 nm of YB was prepared as the second electron injection layer by a vacuum evaporation device.

[0107] Cathode: A Mg:Ag electrode layer with a thickness of 13 nm was evaporated, the mass ratio of Mg to Ag was 1:9, and this layer was the cathode layer.

[0108] Light extraction layer: CPL-1 with a thickness of 65 nm was vacuum-evaporated on the cathode as the light extraction layer.

[0109] The substrate after evaporation was packaged; first, a coating device was used to coat the cover plate after cleaning with UV glue, then the coated cover plate was moved to the pressing section, the substrate after evaporation was placed on the end of the cover plate, and finally the substrate and the cover plate were bonded under the action of the bonding device, and the UV glue was cured by light at the same time.

[0110] The structures of the materials used are shown below:

[0111]

[0112] Device application example 2-Device application example 52, referring to the above method, the compound 2 used in device application example 1 is replaced by compound 160, compound 1, compound 4, compound 6, compound 8, compound 9, compound 12, compound 18, compound 20, compound 25, compound 31, compound 36, compound 42, compound 48, compound 51, compound 53, compound 56, compound 62, compound 66, compound 70, compound 79, compound 85, compound 93, compound 95, compound 105, compound 110, compound 118, compound 121, compound 125, compound 133, compound 137, compound 143, compound 148, compound 152, compound 157, compound 161, compound 167, compound 170, compound 175, compound 189, compound 192, compound 200, compound 212, compound 219, compound 223, compound 229, compound 232, compound 239, compound 241, compound 243, compound 246 as the compound in the NCGL layer, respectively, to prepare the corresponding organic electroluminescent device.

[0113] Device control example: the device control example provides an organic electroluminescent device, the preparation method of the organic electroluminescent device is the only difference from device example 1, the organic electroluminescent device is respectively prepared by using the existing comparative compound a, b, c, d instead of compound 2 in the NCGL layer in the above device example 1 to evaporate, and the device of device control example 1-4 is prepared. Among them, the chemical structural formula of comparative compound a, b, c, d is:

[0114]

[0115] The driving voltage, luminous efficiency and lifetime of the organic electroluminescent devices obtained by the above device examples 2-52 and device control examples 1-4 are characterized at 1000 (nits) brightness, and the test results are as shown in Table 1.

[0116] Table 1

[0117]

[0118]

[0119] Note: in the blue light top emitting device, the current efficiency is greatly affected by the chromaticity, therefore, the influence factor of chromaticity on efficiency is considered, the luminous efficiency and CIEy ratio are defined as BI value, that is, BI=(cd / A) / CIEy.

[0120] As can be seen from Table 1, in the stacked device, the compound provided by the present application has high charge generation ability and high electron transport performance, and can effectively improve the luminous efficiency of the organic electroluminescent device, reduce the driving voltage of the device, and prolong the service life of the organic electroluminescent device. When used as an NCGL material, compared with the comparative compound, the device voltage is reduced, the device efficiency and the device life are improved, which further shows that the compound of the present application has good technical effect when used as an NCGL material in a stacked OLED device.

[0121] The applicant declares that the parent nucleus of the present application is an organic compound containing a furan structure and its application is illustrated by the above examples, but the present application is not limited to the above examples, that is, it does not mean that the present application must rely on the above examples to be implemented. Those skilled in the art should understand that any improvement of the present application, equivalent replacement of the raw materials selected by the present application, addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. An organic compound having a furan structure as a parent nucleus, characterized by comprising: The organic compound is any one of the following compounds:

2. An organic electroluminescent device, characterized by The organic electroluminescence device includes an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, and the organic thin film layer includes the organic compound with the furan-containing structure as the parent nucleus according to claim 1.

3. The organic electroluminescent device according to claim 2, characterized in that The organic thin film layer includes a charge generation layer, and the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, and the material of the N-type charge generation layer includes the organic compound with the furan-containing structure as the parent nucleus according to claim 1. The organic thin film layer further includes any one or a combination of at least two of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, or an electron transport layer.

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