A composition for an organic electroluminescent device and an organic electroluminescent device comprising the same

Abstract

The application discloses a composition for an organic electroluminescent device and an organic electroluminescent device comprising the same, the composition comprising a first compound represented by general formula (1) and a second compound represented by general formula (2): The composition provided by the application is used for an organic electroluminescent device. Preferably, the composition is used as a light-emitting layer material in the organic electroluminescent device. In the organic electroluminescent device prepared by using the composition of the application, the material aggregation can be effectively inhibited, the device efficiency and the service life are improved, and the risk of crucible hole blocking is reduced. Meanwhile, the host of the application can regulate the electron and hole recombination rate, and increase the utilization of the guest to the light-emitting exciton. Moreover, the hexamethyl indene on the guest can also inhibit the aggregation of the host to a certain extent, thereby improving the device efficiency and the service life.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescence technology, and particularly to a composition for an organic electroluminescent device, and an organic electroluminescent device comprising the composition. Background Technology

[0002] Organic light-emitting devices (OLEDs) are current-driven thin-film devices with a sandwich-like structure, consisting of one or more layers of organic functional materials sandwiched between the anode and cathode. Under the influence of an electric field, holes generated at the anode and electrons at the cathode move and are injected into the hole transport layer and electron transport layer, respectively, migrating to the light-emitting layer. When these two electrons recombine in the light-emitting layer, they generate excitons, which excite the light-emitting molecules to ultimately produce visible light. OLEDs are characterized by self-emission, wide viewing angle, wide color gamut, short response time, high luminous efficiency, low operating voltage, low cost, and simple manufacturing process. They can be fabricated into large-size and / or flexible ultra-thin panels. OLEDs are a rapidly developing new display technology with high process integration and are currently widely used in televisions, smartphones, tablets, automotive displays, lighting, and other display products. They will be further applied in large-size displays, flexible screens, and other creative display products.

[0003] For blue light devices, high efficiency and long lifespan have always been the goals pursued by the OLED industry. Currently, the commonly used host material for blue light is anthracene core matrix material; the commonly used guest materials for blue light are mainly pyrene-based and BN-based luminescent materials. Planar anthracene core, pyrene-based, and BN-based materials all exhibit molecular aggregation, thereby reducing the efficiency and lifespan of the device. Summary of the Invention

[0004] Through in-depth research, the inventors discovered that introducing suitable linking fragments into the anthracene core and benzofuran unit, and introducing hexamethylindene into the BN-type luminescent material, can effectively suppress material aggregation, thereby improving device efficiency and lifespan, while reducing the risk of crucible blockage.

[0005] Specifically, to solve the above-mentioned technical problems, the present invention provides: 1) a composition for an organic electroluminescent device, characterized in that the composition comprises a first compound represented by general formula (1) and a second compound represented by general formula (2):

[0006]

[0007] Among them, R1~R 10 Each of the following groups independently represents a hydrogen atom or a substituent, R1 to R2. 10 At least one of them is Ar 1’ The Ar1’ From the following formula Ar 1’ express:

[0008]

[0009] Formula Ar 1’ In the middle, R 11 ~R 13 Each of them independently represents a hydrogen atom or a substituent, and --- represents a single bond connected to the general formula (1);

[0010] R1~R 10 At least one of them is Ar 2’ The Ar 2’ From the following formula Ar 2’ express:

[0011]

[0012] Formula Ar 2’ In the middle, R 14 ~R 17 One of them is a single bond connected to the general formula (1), R 14 ~R 17 The remaining ones and R 18 ~R 21 Each can independently represent a hydrogen atom or a substituent, where X is selected from O, S, or Se;

[0013] R1~R 21 The substituents are independently selected from hydrogen atoms, deuterium atoms, halogen atoms, cyano, nitro, substituted silyl, substituted or unsubstituted alkyl with 1 to 50 carbon atoms, substituted or unsubstituted alkenyl with 1 to 20 carbon atoms, substituted or unsubstituted alkoxy with 1 to 50 carbon atoms, substituted or unsubstituted fluoroalkyl with 1 to 20 carbon atoms, substituted or unsubstituted fluoroalkoxy with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl with 3 to 50 cyclic carbon atoms, substituted or unsubstituted aryl with 6 to 50 cyclic carbon atoms, and substituted or unsubstituted monovalent heterocyclic with 5 to 50 cyclic carbon atoms.

[0014] R1~R 21 Substituent groups can bond with each other to form substituted or unsubstituted saturated or unsaturated rings;

[0015]

[0016] Among them: Ar1, Ar2, Ar3, Ar4, and Ar5 are each independently selected from aryl groups with 6 to 50 cyclic carbon atoms (substituted or unsubstituted), heteroaryl groups with 2 to 30 cyclic carbon atoms (substituted or unsubstituted), fused aryl rings with 10 to 50 cyclic carbon atoms (substituted or unsubstituted), and monovalent fused heterocycles with 6 to 50 cyclic carbon atoms (substituted or unsubstituted).

[0017] At the same time, at least one of Ar1, Ar2, Ar3, Ar4, and Ar5 contains the following aromatic ring structure:

[0018]

[0019] Where: R 22 ~R 25 The substituents are independently selected from single bonds, hydrogen atoms, deuterium atoms, halogen atoms, cyano, nitro, substituted silyl, substituted or unsubstituted alkyl with 1 to 30 carbon atoms, substituted or unsubstituted alkenyl with 1 to 20 carbon atoms, substituted or unsubstituted alkoxy with 1 to 30 carbon atoms, substituted or unsubstituted fluoroalkyl with 1 to 20 carbon atoms, substituted or unsubstituted fluoroalkoxy with 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl with 3 to 30 cyclic carbon atoms, substituted or unsubstituted aryl with 6 to 30 cyclic carbon atoms, and substituted or unsubstituted monovalent heterocyclic with 5 to 30 cyclic carbon atoms.

[0020] R 22 ~R 25 Substituent groups can bond with each other to form substituted or unsubstituted saturated or unsaturated rings.

[0021] 2) The composition for an organic electroluminescent device according to 1), characterized in that the first compound comprises at least one of the following structural formulas:

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] 3) The composition for an organic electroluminescent device according to 1), characterized in that the second compound comprises at least one of the following structural formulas:

[0034]

[0035]

[0036]

[0037] 4) The composition for an organic electroluminescent device according to 1), characterized in that R1 to R 21 The substituents are selected independently from:

[0038] Hydrogen atom, deuterium atom, chlorine atom, bromine atom, fluorine atom, cyano group, nitro group, substituted silyl group, substituted or unsubstituted methyl group, substituted or unsubstituted ethyl group, substituted or unsubstituted n-propyl group, substituted or unsubstituted isopropyl group, substituted or unsubstituted n-butyl group, substituted or unsubstituted isobutyl group, substituted or unsubstituted sec-butyl group, substituted or unsubstituted tert-butyl group, substituted or unsubstituted 2-methylbutyl group, substituted or unsubstituted n-pentyl group, substituted or unsubstituted sec-pentyl group, substituted or unsubstituted trimethylbutyl group Fluoromethyl, substituted or unsubstituted pentafluoroethyl, substituted or unsubstituted 2,2,2-trifluoroethyl, substituted or unsubstituted vinyl, substituted or unsubstituted propenyl, substituted or unsubstituted n-butenyl, substituted or unsubstituted isobutenyl, substituted or unsubstituted n-pentenyl, substituted or unsubstituted isopentenyl, substituted or unsubstituted neopentenyl, substituted or unsubstituted ethynyl, substituted or unsubstituted propynyl, substituted or unsubstituted n-butynyl, substituted or unsubstituted isobutynyl, Substituted or unsubstituted n-pentynyl, substituted or unsubstituted isopentenynyl, substituted or unsubstituted neopentynyl, substituted or unsubstituted cyclopropyl, substituted or unsubstituted cyclobutyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted adamantyl, substituted or unsubstituted thiophene, substituted or unsubstituted indole, substituted or unsubstituted furanyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthraceneyl, substituted or unsubstituted phenanthrene, substituted or unsubstituted indene, substituted or unsubstituted fluorenyl, substituted or unsubstituted spirodifluorenyl, substituted or unsubstituted indofluorenyl, substituted or unsubstituted fluoranyl, substituted or unsubstituted pyrene, substituted or unsubstituted perylyl, substituted or unsubstituted The group includes substituted or unsubstituted tetraphenyl, substituted or unsubstituted benzothiophene, substituted or unsubstituted benzothiophene, substituted or unsubstituted benzofuran, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dibenzofuran, substituted or unsubstituted dibenzoselenyl, and substituted or unsubstituted carbazolyl.

[0039] 5) The composition for an organic electroluminescent device according to claim 1, wherein the "substituted or unsubstituted" in the compound refers to a substituent independently selected from deuterium, tritium, halogen, cyano, nitro, hydroxyl, a monovalent alkyl or cycloalkyl group having 1 to 10 carbon atoms, a monovalent monocyclic aryl or fused-ring aryl group having 6 to 30 carbon atoms, or a monovalent heterocyclic group or fused-ring heteroaryl group having 2 to 50 carbon atoms.

[0040] A second objective of this invention is to provide an application of the composition described in one objective, wherein the composition is used in an organic electroluminescent device. Preferably, the composition serves as both the host material and the guest material of the light-emitting layer in the organic electroluminescent device.

[0041] A third objective of this invention is to provide an organic electroluminescent device. Specifically, an embodiment of this invention provides an organic electroluminescent device comprising a substrate, and an anode layer, a plurality of light-emitting functional layers, and a cathode layer sequentially formed on the substrate; the light-emitting functional layers include any one or at least two combinations of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an exciton blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer. Preferably, at least one of the electron transport layer, the hole blocking layer, and the light-emitting layer contains the composition for an organic electroluminescent device as described in any one of 1) to 5).

[0042] The beneficial effects of this invention include: inserting connecting fragments into the host anthracene core and benzofuran unit; and introducing hexamethylindene into the guest BN-type luminescent material. This effectively suppresses material aggregation, improves device efficiency and lifetime, and reduces the risk of crucible blockage. Furthermore, the host material can regulate the electron-hole recombination rate and increase the guest material's utilization of luminescent excitons. Moreover, the hexamethylindene on the guest material can also suppress host aggregation to a certain extent, thereby improving device efficiency and lifetime. Attached Figure Description

[0043] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0044] Figure 1 The diagram below shows the structure of an organic electroluminescent device using the compounds of this invention. The meanings of each layer in the device are as follows:

[0045] 1. Transparent substrate layer, 2. ITO anode layer, 3. Hole injection layer, 4. Hole transport layer A, 5. Hole transport layer B (or electron blocking layer), 6. Light-emitting layer, 7. Electron transport layer B (or hole blocking layer), 8. Electron transport layer A, 9. Electron injection layer, 10. Cathode reflective electrode layer. Detailed Implementation

[0046] The principles and features of the present invention will be further illustrated below with several synthetic embodiments. The embodiments are only used to explain the present invention, but are not intended to limit the scope of the present invention.

[0047] Unless otherwise stated, the synthesis methods of the specific compounds of formula (1) listed below are carried out in an anhydrous solvent under a protective gas atmosphere.

[0048] Synthesis Example 1: Synthesis of H1

[0049]

[0050] 5.32 g (20.0 mmol, 1.0 eq) of 2-bromo-3'-biphenyl (a1), 4.45 g (21.0 mmol, 1.05 eq) of dibenzofuran-2-boronic acid (b1), and 5.52 g (40 mmol, 2 eq) of potassium carbonate were added, along with 20 mL of water and 50 mL of toluene. The reaction mixture was purged three times under nitrogen protection, and 0.92 g (0.8 mmol, 0.04 eq) of tetrakis(triphenylphosphine)palladium was added. The mixture was heated and stirred under nitrogen protection, and refluxed at 120 °C for 12 h. The reaction was stopped, cooled to room temperature, and 100 mL of deionized water was added. The mixture was extracted three times with ethyl acetate. The solvent was removed by rotary evaporation, and the mixture was separated by silica gel column chromatography. The solvent was evaporated, and the residue was dried under vacuum to obtain 5.80 g of intermediate M1, with a yield of 82%. Mass spectrometry determined the molecular weight to be m / z = 355.1(M+H)+.

[0051] 4.25 g (12.0 mmol, 1.0 eq) of intermediate M1, 3.75 g (12.6 mmol, 1.05 eq) of (10-phenylanthracene-9-yl)boric acid (c1), 5.09 g (24 mmol, 2.00 eq) of potassium phosphate, 20 mL of water, and 40 mL of toluene were added to the reaction mixture. The reaction system was purged three times under nitrogen protection. Then, 0.96 mL (0.96 mmol, 0.08 eq) of a 1 mol / L toluene solution of tri-tert-butylphosphine and 0.22 g (0.24 mmol, 0.02 eq) of tris(dibenzylacetone)palladium were added via syringe. The mixture was heated and stirred under nitrogen protection and refluxed at 120 °C for 12 h. The reaction was stopped, cooled to room temperature, and 100 mL of deionized water was added. The mixture was extracted three times with ethyl acetate. The solvent was removed by rotary evaporation, followed by silica gel column chromatography, solvent removal by rotary evaporation, and vacuum drying to obtain 5.35 g of the target product H1, with a yield of 78%. The solid was a pale yellow color and its molecular weight was determined by mass spectrometry to be m / z = 573.2(M+H)+. Similarly, by changing the reactants, the following compounds can be prepared:

[0052] Table 1

[0053]

[0054]

[0055] Synthesis Example 22: Synthesis of D2

[0056]

[0057] 12.5 g (30.0 mmol, 3.0 eq) of d2, 2.70 g (10 mmol, 1 eq) of 1,3-dibromo-2-chlorobenzene (e2), 0.26 g (0.5 mmol, 0.05 eq) of bis(tris(tert-butyl)phosphine)palladium(0), and 2.88 g (30 mmol, 3.00 eq) of sodium tert-butoxide were added to the reaction mixture. The reaction system was purged three times under nitrogen protection, and then 50 mL of oxygen-free toluene was added via syringe. Under nitrogen protection, the mixture was heated and stirred, and refluxed at 120 °C for 12 h. The reaction was stopped, cooled to room temperature, and 100 mL of deionized water was added. The mixture was extracted three times with ethyl acetate. The solvent was removed by rotary evaporation, separated by silica gel column chromatography, the solvent was evaporated, and the residue was dried under vacuum to obtain 5.85 g of intermediate N2, with a yield of 62%. The molecular weight was determined by mass spectrometry to be m / z = 943.7(M+H)+.

[0058] Under nitrogen protection, 4.72 g (10 mmol, 1.0 eq) of intermediate N2 was added to 40 mL of tert-butylbenzene, and 12 mL (30 mmol, 3.0 eq) of n-butyllithium (2.5 M) was added dropwise at -78 °C. After the addition was complete, the mixture was stirred at 60 °C for 3 hours. Then, 5.0 g (20 mmol, 2 eq) of boron tribromide was added dropwise at -78 °C, and the resulting mixture was stirred at room temperature for 1 hour. Finally, 2.63 g (20 mmol, 2 eq) of N,N-diisopropylethylamine was added dropwise at 0 °C. After the addition was complete, the mixture was stirred at 120 °C for 2 hours. After the reaction was complete, an aqueous sodium acetate solution was added to the reaction mixture at room temperature, stirred, and extracted with ethyl acetate. The solvent was removed by rotary evaporation, separated by silica gel column chromatography, and dried under vacuum to give 2.93 g of intermediate D2, with a yield of 32% and a molecular weight of m / z = 917.7(M+H)+ as determined by mass spectrometry.

[0059] By similarly changing the reactants, the following compounds can be prepared:

[0060] Table 2

[0061]

[0062]

[0063] The film layer function of the organic electroluminescent device involved is described below according to a preferred embodiment of the present invention.

[0064] The organic electroluminescent device described in this invention comprises an anode layer, a cathode layer, and at least one organic layer between the anode and the cathode. Alternatively, the organic layer may be a film layer composed of multiple layers of organic compounds. The organic layer may also contain inorganic compounds.

[0065] At least one organic layer in the organic layer of the organic electroluminescent device described in this invention is a light-emitting layer. Besides the light-emitting layer, the organic layer may also contain other functional layers. For example, one or more hole injection layers, hole transport layers, or electron blocking layers may exist between the anode layer and the light-emitting layer. It is also feasible to have an exciton blocking layer or an intermediate layer with similar function between two light-emitting layers. Similarly, one or more hole blocking layers, electron transport layers, or electron injection layers may exist between the light-emitting layer and the cathode layer. It should be noted that these functional layers are not necessarily present.

[0066] The organic electroluminescent device described in this invention can be a device with a single light emission or a device with multiple light-emitting units connected in series; it can be a monochromatic light-emitting device, a mixed-color device, or a white light-emitting device; furthermore, it can be a bottom-emitting device or a top-emitting device.

[0067] The compounds of the present invention according to the above embodiments can be used in different organic layers. Preferably, the compositions of the present invention are used as blue light-emitting layers in organic electroluminescent devices. The uses of the compositions of the present invention according to the above embodiments are also applicable to organic electronic devices.

[0068] In a preferred embodiment of the present invention, the composition of the present invention is used as both the host and guest material in the light-emitting layer of an organic electroluminescent device. The light-emitting layer in this embodiment can be a single layer or multiple layers.

[0069] When used as the main material, the composition of the present invention can be used alone or in combination with other main materials in the light-emitting layer of the organic electroluminescent device described herein. It should be noted that when multiple main materials are used together, at least one main material is the compound of the present invention, while other main materials can be other compounds of the present invention, or other known or undisclosed main materials. The composition can be used by pre-mixing or co-deposition.

[0070] In a preferred embodiment of the present invention, the doping ratio of the mixture of luminescent material and host material in the luminescent layer of the organic electroluminescent device is preferably 0.1% to 30% by weight of the luminescent material.

[0071] These methods are generally known to those skilled in the art and can be applied to organic electroluminescent devices containing the compositions of the present invention without any inventive effort.

[0072] The following examples, 1-15 and 1-3, detail the application effects of the compounds of the present invention in organic electroluminescent devices, to verify the technical progress and beneficial effects of the compounds of the present invention in the field. The device examples and comparative examples are merely further elaborations of the present invention, but the present invention is not limited by technical conditions.

[0073] Device Example 1: Fabrication of an Organic Electroluminescent Device Used as the Light-Emitting Layer Material

[0074] A 25mm × 75mm × 1.1mm thick glass substrate with an indium tin oxide (ITO) transparent electrode (anode) was ultrasonically cleaned in isopropanol for 5 minutes, followed by ultraviolet (UV)-ozone cleaning for 30 minutes. The ITO film thickness was 130nm. The cleaned glass substrate was then mounted on the substrate holder of a vacuum evaporation apparatus, and a vacuum of 1×10⁻⁶ was applied. -5 ~1×10 -6 A hole injection layer (HIL) with a thickness of 15 nm is deposited on an ITO transparent conductive layer. A hole transport layer (HTL) with a thickness of 60 nm is then deposited on top of the hole injection layer. Subsequently, an electron blocking layer (EBL) with a thickness of 5 nm is deposited on top of the hole transport layer. Next, an emissive layer (EML) with a thickness of 20 nm is co-deposited on top of the electron blocking layer. The emissive layer (EML) uses a multi-source co-deposition method to deposit the luminescent material and the host material, with the luminescent material having a doping concentration of 2% by weight. To ensure the accuracy of the luminescent material doping concentration, the evaporation rates of the luminescent material and the host material are allowed to stabilize before the shielding barrier is opened for multi-source co-deposition. Then, a hole blocking layer (HBL) with a thickness of 10 nm is deposited on top of the emissive layer. Finally, an electron transport layer (ETL) with a thickness of 25 nm is co-deposited on top of the hole blocking layer. Furthermore, an electron injection electrode (EIL) of lithium 8-hydroxyquinoline (Liq) with a film thickness of 1 nm was deposited on top of the ETL. Then, an aluminum (Al) metal cathode with a film thickness of 80 nm was deposited on top of the EIL. The organic electroluminescent device structure of Example 1 is as follows. Figure 1 As shown, Figure 1 It also shows the stacking order and function of each functional layer.

[0075] The OLED, in principle, has the following layer structure: substrate / hole injection layer (HIL) / hole injection layer (HTL) / electron blocking layer (EBL) / emitting layer (EML) / hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) and finally, a cathode. The exact structure of the OLED is shown in Table 3.

[0076] Table 3 Materials used in OLEDs

[0077]

[0078] Device Example 1:

[0079] ITO(130) / HATCN(15) / HTL(60) / EBL(5) / H1:BD-1(20, 2% by weight) / HBL(10) / ETL:Liq(25, 50% by weight) / Liq(1) / Al(80), it should be noted that the numbers in parentheses represent the film thickness (unit: nm).

[0080] Device Example 2:

[0081] ITO(130) / HATCN(15) / HTL(60) / EBL(5) / H241:BD-2(20, 2% by weight) / HBL(10) / ETL:Liq(25, 50% by weight) / Liq(1) / Al(80), it should be noted that the numbers in parentheses represent the film thickness (unit: nm).

[0082] Device Example 3:

[0083] ITO(130) / HATCN(15) / HTL(60) / EBL(5) / BH-1:D2(20, 2% by weight) / HBL(10) / ETL:Liq(25, 50% by weight) / Liq(1) / Al(80), it should be noted that the numbers in parentheses represent the film thickness (unit: nm).

[0084] Device Example 4:

[0085] ITO(130) / HATCN(15) / HTL(60) / EBL(5) / BH-2:D10(20, 2% by weight) / HBL(10) / ETL:Liq(25, 50% by weight) / Liq(1) / Al(80), it should be noted that the numbers in parentheses represent the film thickness (unit: nm).

[0086] Device Example 5:

[0087] ITO(130) / HATCN(15) / HTL(60) / EBL(5) / H1:D2(20, 2% by weight) / HBL(10) / ETL:Liq(25, 50% by weight) / Liq(1) / Al(80), it should be noted that the numbers in parentheses represent the film thickness (unit: nm).

[0088] The only difference between Device Examples 6-15 and Device Example 5 is that the composition H1:D2 used in the light-emitting layer of the present invention is replaced with other compositions of the present invention, as detailed in Table 4.

[0089] Comparative Examples 1-3:

[0090] The difference between this comparative example and device example 5 is that BH and BD in the organic electroluminescent device are changed to those that are well-known in the industry and have been commercially applied. The device performance test data obtained are shown in Table 4.

[0091] The OLED was characterized using standard methods. For this purpose, the electroluminescence spectrum, current efficiency (measured in cd / A), power efficiency (measured in lm / W), and external quantum efficiency (EQE, measured as a percentage) were determined, calculated as a function of luminous density from the current / voltage / luminous density characteristic line (IUL characteristic line) exhibiting Lambertian emission characteristics. At 1000 cd / m²... 2 The required voltage V1000 is determined at a brightness level of 1000 cd / m². CE1000 indicates the voltage required at 1000 cd / m². 2 The achieved current efficiency. Finally, EQE1000 indicates an efficiency of 1000 cd / m². 2 The external quantum efficiency at operating brightness, T90, indicates the device's efficiency at 1000 cd / m². 2 The operating time from the initial brightness of the device to 90% of its original brightness. The device performance of Examples 1-7 and Comparative Examples 1-3 of the present invention is summarized in Table 4.

[0092] Table 4

[0093]

[0094]

[0095] As can be seen from Table 4, compared with the prior art, using the devices of Embodiments 1-16 of the present invention can improve efficiency and lifetime while maintaining a slight reduction in the driving voltage of the OLED. For example, T90 in Device Embodiment 1 (H1) is improved by 13% compared with Comparative Example 2; CE1000 in Device Embodiment 4 (D10) is improved by 23% compared with Comparative Example 2. More importantly, when BH and BD of the present invention are used in combination, efficiency and lifetime are significantly improved. For example, CE1000 and T90 in Device Embodiment 12 (H241 and D43) are improved by 42% and 32% respectively compared with Comparative Example 2.

Claims

1. A composition for use in organic electroluminescent devices, characterized in that, The composition comprises a first compound represented by general formula (1) and a second compound represented by general formula (2): General formula (1) General formula (2) The first compound is selected from at least one of the following structural formulas: ； The second compound is selected from at least one of the following structural formulas: 。 2. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and at least one organic thin film located between the anode and the cathode, the organic thin film containing the composition for an organic electroluminescent device as described in claim 1.

3. The organic electroluminescent device according to claim 2, characterized in that, The composition for organic electroluminescent devices serves as both the host and guest material for the light-emitting layer.

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