Organic electroluminescent device and use thereof

Abstract

The application provides an organic electroluminescent device and application thereof, and belongs to the technical field of organic electroluminescent devices. The organic electroluminescent device is prepared by combining a compound shown in formula I in a hole transport region and a blue light dopant material shown in formula II in a light-emitting layer. The compound can still have excellent luminous efficiency, long service life and low driving voltage under high brightness.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic electroluminescent devices, and relates to an organic electroluminescent device and application thereof. BACKGROUND

[0002] An organic light emitting diode (OLED) has the advantages of thinness, lightness, active light emission, wide viewing angle, fast response, low energy consumption, excellent low-temperature and anti-vibration performance, and potential flexible design. The OLED is a full-solid device, has no vacuum cavity and no liquid component, and is therefore not afraid of vibration, is convenient to use, has high resolution, a wide viewing angle, and a wide working temperature range, and the like, so that the use scenarios of the OLED device are increasingly wide.

[0003] A blue OLED is a key to realizing full-color display. By combining red, green and blue OLEDs, a rich and colorful image can be generated, and the blue OLED is widely applied to display devices such as televisions, mobile phones, tablet computers and the like. The blue organic electroluminescent device is a weak link in the development of full-color OLEDs, and the performance such as efficiency and service life of the blue light device has been difficult to improve comprehensively so far, and the service life may be attenuated for a long time, which needs to be solved by optimizing the material and the device structure.

[0004] Therefore, it is a technical problem to be solved by those skilled in the art to provide an OLED display device with excellent light-emitting efficiency, long service life and low driving voltage. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide an organic electroluminescent device and application thereof. The organic electroluminescent device prepared by combining a compound represented by formula I in the hole transport region and a blue light doping material represented by formula II in the light-emitting layer has excellent light-emitting efficiency, long service life and low driving voltage under high brightness.

[0006] To achieve the purpose of the present application, the following technical solutions are adopted:

[0007] In one aspect, the present application provides an organic electroluminescent device, which comprises a first electrode, a second electrode facing the first electrode, a light-emitting layer between the first electrode and the second electrode, and a hole transport region between the first electrode and the light-emitting layer.

[0008] The hole transport region comprises a compound represented by formula I.

[0009]

[0010] X in formula I is O or S.

[0011] Ar is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthryl and phenanthryl, and Ar is fused and cyclic with the adjacent benzene ring on the mother nucleus at 1,2-, 2,3- or 3,4-position of the benzene ring;

[0012] L is selected from a bond or When L is a bond, the N atom is directly connected to the benzene ring;

[0013] R3 is selected from any one of substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3- to 30-membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted 3- to 30-membered heteroaryl, and the heteroatom in the heterocycloalkyl and heteroaryl is independently selected from oxygen, nitrogen or sulfur;

[0014] R1 is selected from any one of hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3- to 30-membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted 3- to 30-membered heteroaryl, and the heteroatom in the heterocycloalkyl and heteroaryl is independently selected from oxygen, nitrogen or sulfur;

[0015] Ar1 and Ar2 are each independently selected from any one of substituted or unsubstituted 3- to 30-membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted 3- to 30-membered heteroaryl, and the heteroatom in the heterocycloalkyl and heteroaryl is independently selected from oxygen, nitrogen or sulfur.

[0016] Further preferably, L is selected from a bond or any one of the following groups:

[0017]

[0018] * represents the connection site of the group.

[0019] Further preferably, R1 is selected from hydrogen or any one of the following groups:

[0020]

[0021] * represents the connection site of the group.

[0022] Further preferably, Ar1 and Ar2 are the same as or different from each other and are each independently selected from one or a combination of several groups of the following groups:

[0023]

[0024] * represents the point of attachment of the radical.

[0025] The dopant material in the light-emitting layer is a compound of formula II:

[0026]

[0027] In formula II,

[0028] R4is selected from the group consisting of a substituted or unsubstituted diarylamine group, a substituted or unsubstituted C1-C30alkyl group, a substituted or unsubstituted C6-C30aryl group;

[0029] R a -R d each independently of one another, is selected from the group consisting of a substituted or unsubstituted C1-C30alkyl group, a substituted or unsubstituted C6-C30aryl group;

[0030] R4, R a -R d each independently represents a mono-, di-, tri-, tetra-, penta- or unsubstituted radical;

[0031] In case R4is selected from the group consisting of a diarylamine group, formula II is selected from the group consisting of formula II-1, R a In case R4is selected from the group consisting of a substituted or unsubstituted C6-C30aryl group, formula II is selected from the group consisting of formula II-2:

[0032]

[0033] In the substituted radicals of formula I and formula II, the substituents are selected from any one or a combination of at least two of deuterium, a C1-C30alkyl group or a C6-C30aryl group.

[0034] Further preferably, the compound of formula I can be exemplified by, but is not limited to, the following compounds:

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] Preferably, the dopant material selected from the group consisting of a compound of formula II can be exemplified by, but is not limited to, the following compounds:

[0042]

[0043]

[0044]

[0045] When R4 is diarylamino group, the second hole transport layer material of the present application can be effectively improved in device efficiency when combined with boron-nitrogen-based doped compounds. When R4 is aryl group, substitution at the ortho position of the phenyl group can significantly improve the device lifetime when combined with the second hole transport layer material of the present application. a

[0046] In the present application, the compounds of formula I and formula II are known in the art.

[0047] For the starting materials not disclosed, the skilled person can employ classical Suzuki coupling reaction (Suzuki reaction), Buchwald-Hartwig coupling reaction (Buchwald-Hartwig reaction) synthesis and apply it to the present application.

[0048] The compounds of formula I in the present application can be synthesized by referring to the following reaction scheme:

[0049]

[0050] wherein Hal1, Hal2 and Hal3 are each independently selected from halogen.

[0051] The specific steps of the above synthesis route are as follows:

[0052] (1) Dissolve the starting material A and starting material B in toluene, then add Pd2(dba)3 (tris(dibenzylideneacetone)dipalladium), P(t-Bu)3 (tri(tert-butyl)phosphine) and t-BuONa (sodium tert-butoxide) under N2 atmosphere, warm up to 105-115°C and stir for 8-12h, then after the reaction is completed, hot filter with diatomite to remove salt and catalyst, cool the filtrate to room temperature, then add distilled water to the filtrate for washing, separate the organic phase after separation, extract the aqueous phase with ethyl acetate, then dry the combined organic layer with magnesium sulfate, remove the solvent with a rotary evaporator, finally purify the remaining substance with column chromatography using a mixture of dichloromethane and petroleum ether as eluent to obtain the compound shown in intermediate 1.

[0053] ​(2) After dissolving the intermediate 1 and the raw material C in toluene, Pd2(dba)3, P(t-Bu)3, and t-BuONa are added under N2atmosphere, the temperature is raised to 105-115°C, and the reaction is stirred for 8-12 hours. After the reaction is completed, the reaction solution is filtered hot using celite to remove the salt and catalyst. After the reaction solution is cooled to room temperature, distilled water is added to the reaction solution to wash, and the organic layer is separated. The water layer is extracted with ethyl acetate, and the combined organic layer is dried using magnesium sulfate. The solvent is removed using a rotary evaporator, and the remaining material is purified by column chromatography using a mixture of dichloromethane and petroleum ether as an eluent to obtain the compound represented by intermediate 2.

[0054] (3) Under N2protection, the intermediate 2, the raw material D, tetrakis(triphenylphosphine)palladium, and potassium carbonate are added to a mixed solvent of toluene, ethanol, and water, respectively, and the temperature is raised to 90-100°C to react for 8-10 hours. After the reaction is completed, the reaction solution is cooled to room temperature, and the solid is precipitated. After the solid is completely precipitated, the reaction solution is filtered, and the salt is removed by washing with water. The filtered cake is washed with a small amount of ethanol, dried, recrystallized in a methanol solution, and the compound represented by the above general formula 1 is obtained.

[0055] The compound of formula II according to the present application can be synthesized by referring to the following reaction scheme:

[0056]

[0057] A flask containing the raw material a, the raw material b, Pd2(dba)3, P(t-Bu)3, NaOtBu, and a toluene solution is heated to 110-120°C and stirred for 8-10 hours. The reaction solution is cooled to room temperature, and water and ethyl acetate are added to separate the liquid layer. Then, the solvent is distilled off under reduced pressure, and the resulting material is purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 50% / 50% (volume / volume)) to obtain the compound represented by intermediate 1.

[0058] A flask containing the intermediate 1, the raw material c, Pd2(dba)3, P(t-Bu)3, NaOtBu, and a toluene solution is heated to 110-120°C and stirred for 8-10 hours. The reaction solution is cooled to room temperature, and water and ethyl acetate are added to separate the liquid layer. Then, the solvent is distilled off under reduced pressure, and the resulting material is purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 50% / 50% (volume / volume)) to obtain the compound represented by intermediate 2.

[0059] Under a nitrogen atmosphere, a tert-butyl lithium pentane solution was added to a flask containing intermediate 2 and tert-butylbenzene at -40°C. After completion of the dropwise addition, the temperature was raised to 70-80°C, and the mixture was stirred for 1-2 hours, and pentane was distilled off. After cooling to -40°C, boron tribromide was added thereto, and the mixture was raised to room temperature and stirred for 1-2 hours. Thereafter, the mixture was again cooled to 0°C, and N,N-diisopropylethylamine was added thereto and stirred at room temperature, and then stirred at 90-100°C for 2-3 hours. The reaction solution was cooled to 0°C and potassium acetate saturated solution and ethyl acetate were added thereto to separate the liquid layer. Then the solvent was distilled off under reduced pressure. It was purified by silica gel column chromatography (developing agent: hexane / dichloromethane = 40 / 1 (volume / volume)) to obtain a compound represented by Chemical Formula II.

[0060] Preferably, the hole transport region includes at least a hole injection layer, a first hole transport layer, a second hole transport layer, and the second hole transport layer is a compound represented by Formula I.

[0061] The organic electroluminescent device of the present application can be a top emission type, a bottom emission type, or a bidirectional emission type. The device described in the present application can be used in an organic light emitting device, an organic solar cell, electronic paper, an organic photoreceptor, or an organic thin film transistor.

[0062] The organic light emitting device can have a structure including a hole injection layer, a hole transport layer, an electron blocking layer, a second hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and the like as organic layers. However, the structure of the organic light emitting device is not limited thereto, and can include a smaller or larger number of organic layers.

[0063] The organic light emitting device can be manufactured by sequentially stacking a first electrode, an organic layer, and a second electrode on a substrate. The manufacturing can be performed by a physical vapor deposition (PVD) method such as sputtering or e-beam evaporation.

[0064] A first electrode is formed by evaporating a metal or a metal oxide having conductivity or an alloy thereof on a substrate, an organic layer including a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer is formed on the first electrode, and a substance that can be used as a second electrode is evaporated on the organic layer. In addition to such a method, an organic light emitting device can be manufactured by sequentially evaporating a second electrode substance, an organic layer, a first electrode substance on a substrate.

[0065] Further, with respect to the compound represented by the above formula I, formula II, in the production of an organic light emitting device (or element), not only a vacuum evaporation method but also a solution coating method can be used to form an organic layer. The solution coating method includes, but is not limited to, a spin coating method, a dip coating method, a blade coating method, an inkjet printing method, a screen printing method, a spray method, a roll coating method, and the like.

[0066] The first electrode is an anode, and the second electrode is a cathode.

[0067] As the anode material, in order to smoothly inject holes into the organic layer, a material having a large work function is preferable. Specific examples of the anode material that can be used in the present application include metals such as vanadium, chromium, copper, zinc, gold, and alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), and the like; combinations of a metal and an oxide such as ZnO:Al or SnO2:Sb; and electrically conductive polymers such as polypyrrole and polyaniline.

[0068] As the cathode material, in order to easily inject electrons into the organic layer, a material having a small work function is preferable. Specific examples of the cathode material include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, and alloys thereof; multilayered structure materials such as LiF / Al or LiO2 / Al, and Mg / Ag; and the like.

[0069] The hole transport region means a region in which holes are transported between the first electrode and the light emitting layer. The hole transport region is a region that receives holes from the hole injection layer and transports the holes to the light emitting layer. The hole transport region can be disposed between the anode (or the hole injection layer) and the light emitting layer. The hole transport region can be used to smoothly move holes transferred from the anode to the light emitting layer and to block electrons transferred from the cathode to remain in the light emitting layer.

[0070] In the present application, the hole injection layer is preferably a p-doped hole injection layer, which means a hole injection layer doped with a p-dopant. The p-dopant is a material that imparts a p-type semiconductor property. The p-type semiconductor property means a property of injecting or transporting holes at the HOMO level, i.e., a property of a material having a high hole conductivity.

[0071] The second hole transport layer can be disposed between the anode and the light emitting layer, or between the cathode and the light emitting layer. When the second hole transport layer is disposed between the anode and the light emitting layer, it can be used to promote hole injection and / or hole transport, or to prevent electron overflow. When the second hole transport layer is disposed between the cathode and the light emitting layer, it can be used to promote electron injection and / or electron transport, or to prevent hole overflow.

[0072] The light emitting substance of the light emitting layer is a substance capable of receiving holes and electrons from the hole transport layer and the electron transport layer, respectively, and emitting light in the visible light region by combining the holes and the electrons, and is preferably a substance having high quantum efficiency for fluorescence or phosphorescence.

[0073] The electron transport region can include at least one of an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer, and preferably at least one of the electron transport layer and the electron injection layer. The electron transport region is a layer capable of improving a problem of deterioration of light emitting brightness due to a change in current characteristics in the device when the device is exposed to high temperature during a process of manufacturing a panel, and it can control charge flow characteristics.

[0074] In addition to the specific combination of including Formula I in the second hole transport layer and including Formula II in the light emitting layer as disclosed herein, there is no particular limitation on the materials for other layers in the OLED device. Existing hole injection materials, hole transport materials, host materials, hole blocking layer materials, electron transport layer materials, and electron injection materials can be used.

[0075] The hole injection layer material has metal porphyrin, oligothiophene, arylamine derivative, hexacyno hexaazatriphenylene derivative, quinacridone derivative, perylene derivative, anthraquinone, and polyaniline and polythiophene conductive polymer, and the P-doped P-dopant can be exemplified by the following compounds, but is not limited thereto:

[0076]

[0077]

[0078] The first hole transport material can be selected from arylamine derivative, conductive polymer, and block copolymer having both conjugated portion and non-conjugated portion, and specifically, the first hole transport material is selected from the following compounds, but is not limited thereto:

[0079]

[0080]

[0081] The second hole transport layer of the present application is a compound represented by Formula I.

[0082] The host material preferably uses the following anthracene compound, but is not limited thereto:

[0083]

[0084] The dopant material of the present application is a compound represented by Formula II.

[0085] The material of the electron transport layer (hole blocking layer) can be oxazole, imidazole, thiazole, triazine, metal chelate, quinoline derivative, oxinyl derivative, dioxazine derivative, phenanthroline derivative, silicon-containing heterocyclic compound, perfluorinated oligomer, etc., and specifically, the electron transport layer material is selected from the following compounds, but is not limited thereto:

[0086]

[0087] The electron injection layer material specifically includes fluorenone, anthraquinone dimethane, diphenylquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylene tetracarboxylic acid, fluorenylmethane, anthrone, and derivatives, metal complexes, and nitrogen-containing 5-membered ring derivatives thereof, but is not limited thereto.

[0088] On the other hand, the present application provides a display panel comprising the organic electroluminescent device as described above.

[0089] On the other hand, the present application provides the use of the organic electroluminescent device as described above in an organic light-emitting device, an organic solar cell, electronic paper, an organic photoreceptor, or an organic thin film transistor.

[0090] Compared with the prior art, the present application has the following beneficial effects:

[0091] The organic electroluminescent device prepared by the combination of the compound of formula I and the blue dopant material of formula II in the light-emitting layer has a more suitable HOMO energy level of the compound of formula I as the second hole transport layer and the dopant material of formula II, which makes the exciton more effectively transfer, so that the device has excellent performance, lower driving voltage, and solves the problems of the lifetime decay and efficiency decline of the organic electroluminescent device. DETAILED DESCRIPTION

[0092] The technical solutions of the present application are further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitations on the present application.

[0093] Example 1

[0094]

[0095] After dissolving raw material A (1.0 eq, CAS: 125404-00-4) and raw material B (1.0 eq, CAS: 204530-94-9) in toluene, Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under N2 atmosphere, the temperature was raised to 115°C and the reaction was stirred for 12 h. After the reaction was completed, the hot filter was extracted using diatomite to remove the salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After the liquid-liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried using magnesium sulfate. The solvent was removed using a rotary evaporator, and finally, the residue was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:16) as the eluent to obtain the compound shown in intermediate 1 (yield: 80.21%).

[0096] After dissolving intermediate 1 (1.0 eq) and raw material C (1.0 eq, CAS: 108313-41-3) in toluene, Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under N2 atmosphere, the temperature was raised to 115°C and the reaction was stirred for 8 h. After the reaction was completed, the hot filter was extracted using diatomite to remove the salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After the liquid-liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried using magnesium sulfate. The solvent was removed using a rotary evaporator, and finally, the residue was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:8) as the eluent to obtain the compound shown in intermediate 2 (yield: 75.34%).

[0097] Under N2 protection, intermediate 2 (1.0 eq), raw material D (1.0 eq, CAS: 1446515-26-2), tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added to a mixed solvent of toluene, ethanol and water, respectively, the temperature was raised to 100°C and the reaction was carried out for 10 h. After the reaction was completed, the temperature was cooled to room temperature, and after the solid was completely precipitated, it was filtered and washed with water to remove the salt, then washed with a small amount of ethanol, the filter cake was dried, recrystallized in methanol solution to obtain compound 1; (yield: 78.52%).

[0098] The obtained compound 1 was detected and analyzed, and the results were as follows:

[0099] HPLC purity: >99.95%.

[0100] MS (ESI, m / Z): [M+H]+: 713.36.

[0101] Elemental analysis:

[0102] Calculated values: C, 90.85; H, 4.94; N, 1.96; O, 2.24.

[0103] The test values ​​are: C, 90.16; H, 5.45; N, 2.28; O, 2.53.

[0104] Example 2

[0105]

[0106] Raw material A (1.0 eq, CAS: 125404-00-4) and raw material B (1.0 eq, CAS: 204530-94-9) were dissolved in toluene, and Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under a N2 atmosphere. The temperature was raised to 115°C and stirred for 12 hours. After the reaction, the salt and catalyst were removed by hot filtration using diatomaceous earth. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate. The combined organic layers were dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. Finally, the remaining substance was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:16) as eluent to obtain the compound shown in Intermediate 1 (yield: 77.58%).

[0107] Intermediate 1 (1.0 eq) and raw material C (1.0 eq, CAS: 108313-41-3) were dissolved in toluene, and Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under a N2 atmosphere. The temperature was raised to 115°C and stirred for 8 hours. After the reaction, the salt and catalyst were removed by hot filtration using diatomaceous earth. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained and the aqueous phase was extracted with ethyl acetate. The combined organic layers were dried over magnesium sulfate and the solvent was removed using a rotary evaporator. Finally, the remaining substance was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:8) as an eluent to obtain the compound shown in Intermediate 2 (yield: 78.29%).

[0108] Intermediate 2 (1.0 eq), starting material D (1.0 eq, CAS: 1548470-92-3), tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added to a mixture solvent of toluene, ethanol and water respectively under N2 protection, and the reaction was carried out at 100°C for 10 h. After the reaction was completed, the mixture was cooled to room temperature, and the solid was allowed to precipitate completely. After filtration, the salt was removed by washing with water, and then the residue was washed with a small amount of ethanol, and the filter cake was dried and recrystallized in methanol to obtain compound 2 (yield: 74.96%).

[0109] The obtained compound 2 was subjected to detection analysis, and the results were as follows:

[0110] HPLC purity: >99.95%.

[0111] MS (ESI, m / Z): [M+H]+: 713.41.

[0112] Elemental analysis:

[0113] Calculated value: C, 90.85; H, 4.94; N, 1.96; O, 2.24.

[0114] Test value: C, 90.21; H, 5.34; N, 2.32; O, 2.36.

[0115] Example 3

[0116]

[0117] Starting material A (1.0 eq, CAS: 125404-00-4) and starting material B (1.0 eq, CAS: 204530-94-9) were dissolved in toluene, and then Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under N2 atmosphere. The reaction was carried out at 115°C for 12 h. After the reaction was completed, the mixture was hot-filtered with diatomite to remove the salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After the liquid was separated, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate. Then, the combined organic layer was dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. Finally, the remaining material was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V=1:16) as the eluent to obtain the compound shown in intermediate 1 (yield: 79.26%).

[0118] After intermediate 1 (1.0 eq) and raw material C (1.0 eq, CAS: 108313-41-3) were dissolved in toluene, Pd2(dba)3(0.01 eq), P(t-Bu)3(0.5 eq) and t-BuONa (2.0 eq) were added under N2 atmosphere, the reaction was heated to 115℃ and stirred for 8 h. After the reaction was completed, the filtrate was hot-filtrated using diatomite to remove the salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After the liquid-liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried using magnesium sulfate, and the solvent was removed using a rotary evaporator. Finally, the remaining substance was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:8) as the eluent, to obtain the compound shown in intermediate 2 (yield: 75.34%).

[0119] Under N2 protection, intermediate 2 (1.0 eq), raw material D (1.0 eq, CAS: 1256544-74-7), tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added to a mixed solvent of toluene, ethanol and water, respectively, and the reaction was heated to 100℃ for 10 h. After the reaction was completed, the reaction was cooled to room temperature, and after the solid was completely precipitated, it was filtered and washed with water to remove the salt, then washed with a small amount of ethanol, and the filter cake was dried and recrystallized in a methanol solution to obtain compound 4; (yield: 81.57%).

[0120] The obtained compound 4 was detected and analyzed, and the results were as follows:

[0121] HPLC purity: >99.95%.

[0122] MS (ESI, m / Z): [M+H]+: 713.40.

[0123] Elemental analysis:

[0124] Calculated value: C, 90.85; H, 4.94; N, 1.96; O, 2.24.

[0125] Test value: C, 90.01; H, 5.29; N, 2.22; O, 2.41.

[0126] Example 4

[0127]

[0128] After dissolving raw material A (1.0 eq, CAS: 125404-00-4) and raw material B (1.0 eq, CAS: 204530-94-9) in toluene, Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under N2 atmosphere, the temperature was raised to 115℃ and the reaction was stirred for 12 h. After the reaction was completed, the hot filter was extracted using diatomite to remove the salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After the liquid-liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried using magnesium sulfate. The solvent was removed using a rotary evaporator, and finally, the residue was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:16) as the eluent to obtain the compound shown in intermediate 1 (yield: 80.29%).

[0129] After dissolving intermediate 1 (1.0 eq) and raw material C (1.0 eq, CAS: 108313-41-3) in toluene, Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under N2 atmosphere, the temperature was raised to 115℃ and the reaction was stirred for 8 h. After the reaction was completed, the hot filter was extracted using diatomite to remove the salt and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After the liquid-liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layer was dried using magnesium sulfate. The solvent was removed using a rotary evaporator, and finally, the residue was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:8) as the eluent to obtain the compound shown in intermediate 2 (yield: 76.49%).

[0130] Under N2 protection, intermediate 2 (1.0 eq), raw material D (1.0 eq, CAS: 1627917-17-2), tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added to a mixed solvent of toluene, ethanol and water, respectively, the temperature was raised to 100℃ and the reaction was carried out for 10 h. After the reaction was completed, the temperature was cooled to room temperature, and after the solid was completely precipitated, it was filtered and washed with water to remove the salt, then washed with a small amount of ethanol, the filter cake was dried, recrystallized in methanol solution to obtain compound 5; (yield: 78.11%).

[0131] The obtained compound 5 was detected and analyzed, and the results were as follows:

[0132] HPLC purity: >99.95%.

[0133] MS (ESI, m / Z): [M+H]+: 713.45.

[0134] Elemental analysis:

[0135] Calculated values: C, 90.85; H, 4.94; N, 1.96; O, 2.24.

[0136] The test values ​​are: C, 90.25; H, 5.24; N, 2.22; O, 2.41.

[0137] Example 5

[0138]

[0139] Raw material A (1.0 eq, CAS: 125404-00-4) and raw material B (1.0 eq, CAS: 204530-94-9) were dissolved in toluene, and Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under a N2 atmosphere. The temperature was raised to 115°C and stirred for 12 hours. After the reaction, the salt and catalyst were removed by hot filtration using diatomaceous earth. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate. The combined organic layers were dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. Finally, the remaining substance was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:16) as eluent to obtain the compound shown in Intermediate 1 (yield: 79.88%).

[0140] Intermediate 1 (1.0 eq) and raw material C (1.0 eq, CAS: 108313-41-3) were dissolved in toluene, and Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.5 eq) and t-BuONa (2.0 eq) were added under a N2 atmosphere. The temperature was raised to 115°C and stirred for 8 hours. After the reaction, the salt and catalyst were removed by hot filtration using diatomaceous earth. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. After separation, the organic phase was retained and the aqueous phase was extracted with ethyl acetate. The combined organic layers were dried over magnesium sulfate and the solvent was removed using a rotary evaporator. Finally, the remaining substance was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:8) as an eluent to obtain the compound shown in Intermediate 2 (yield: 75.92%).

[0141] The intermediate 2 (1.0 eq), raw material D (1.0 eq, CAS: 2261008-20-0), tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added to a mixed solvent of toluene, ethanol and water under N2protection, respectively, and heated to 100°C for 10h. After the reaction was completed, it was cooled to room temperature. After the solid was completely precipitated, it was filtered and washed with water to remove the salt, then washed with a small amount of ethanol, and the filter cake was dried and recrystallized in a methanol solution to obtain compound 6; (yield: 76.47%).

[0142] The obtained compound 6 was detected and analyzed, and the results were as follows:

[0143] HPLC purity: >99.95%.

[0144] MS (ESI, m / Z): [M+H]+: 713.39.

[0145] Elemental analysis:

[0146] Calculated value: C, 90.85; H, 4.94; N, 1.96; O, 2.24.

[0147] Test value: C, 90.31; H, 5.30; N, 2.24; O, 2.37.

[0148] Example 6

[0149]

[0150] A flask containing raw material a (1.0 eq, CAS: 2409562-95-2), raw material b (1.0 eq, CAS: 2648147-42-4), Pd2(dba)3(0.02 eq), P(t-Bu)3(0.5 eq), NaOtBu (2.0 eq) and toluene solution was heated to 120°C and stirred for 8 hours. The reaction solution was cooled to room temperature, and water and ethyl acetate were added to separate the liquid layer. Then the solvent was removed by distillation under reduced pressure and purified by silica gel column chromatography (developing agent: hexane / ethyl acetate = 50% / 50% (volume / volume)) to obtain the compound shown in intermediate 1. (yield: 64.35%).

[0151] A flask containing intermediate 1 (1.0 eq), starting material c (1.0 eq, CAS: 3034693-54-1), Pd2(dba)3(0.02 eq), P(t-Bu)3(0.5 eq), NaOtBu (2.0 eq) and toluene solution was heated to 120 °C and stirred for 8 hours. The reaction solution was cooled to room temperature, and water and ethyl acetate were added to separate the liquid layer. Then the solvent was removed by distillation under reduced pressure and purified by silica gel column chromatography (developing agent: hexane / ethyl acetate = 50 / 50 (volume / volume)) to obtain the compound shown in intermediate 2 (yield: 59.87%).

[0152] Under a nitrogen atmosphere, tert-butyl lithium pentane solution (5.0 eq) was added to a flask containing intermediate 2 (1.0 eq) and tert-butyl benzene solution at -40 °C. After completing the dropwise addition, the temperature was raised to 70 °C, and the mixture was stirred for 1 hour, and pentane was distilled off. After cooling to -40 °C, boron tribromide (3.0 eq) was added thereto, and the mixture was raised to room temperature and stirred for 1 hour. Thereafter, the mixture was again cooled to 0 °C, and N,N-diisopropyl ethylamine (3.0 eq) was added thereto and stirred at room temperature, and then stirred at 100 °C for 3 hours. The reaction solution was cooled to 0 °C and potassium acetate saturated solution and ethyl acetate were added thereto to separate the liquid layer. Then the solvent was removed by distillation under reduced pressure. It was purified by silica gel column chromatography (developing agent: hexane / dichloromethane = 40 / 1 (volume / volume)) to obtain compound BD-1. (yield: 42.8%).

[0153] The resulting compound BD-1 was subjected to detection analysis, and the results were as follows:

[0154] HPLC purity: >99.95%.

[0155] MS (ESI, m / Z): [M+H]+: 999.66.

[0156] Elemental analysis:

[0157] Calculated value: C, 84.06; H, 7.46; N, 4.20; S, 3.21; B, 1.08.

[0158] Test value: C, 83.66; H, 7.69; N, 4.35; S, 3.25; B, 1.18.

[0159] Example 7

[0160]

[0161] A flask containing starting material a (1.0 eq, CAS: 2409562-95-2), starting material b (1.0 eq, CAS: 2648147-42-4), Pd2(dba)3 (0.02 eq), P(t-Bu)3 (0.5 eq), NaOtBu (2.0 eq) and toluene solution was heated to 120 °C and stirred for 8 hours. The reaction solution was cooled to room temperature, and water and ethyl acetate were added to separate the liquid layer. Then the solvent was removed by distillation under reduced pressure and purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 50 / 50 (volume / volume)) to obtain the compound shown in Intermediate 1; (yield: 67.51%).

[0162] A flask containing Intermediate 1 (1.0 eq), starting material c (1.0 eq, CAS: 2262575-20-0), Pd2(dba)3 (0.02 eq), P(t-Bu)3 (0.5 eq), NaOtBu (2.0 eq) and toluene solution was heated to 120 °C and stirred for 8 hours. The reaction solution was cooled to room temperature, and water and ethyl acetate were added to separate the liquid layer. Then the solvent was removed by distillation under reduced pressure and purified by silica gel column chromatography (eluent: hexane / ethyl acetate = 50 / 50 (volume / volume)) to obtain the compound shown in Intermediate 2; (yield: 52.31%).

[0163] Under a nitrogen atmosphere, tert-butyl lithium pentane solution (5.0 eq) was added to a flask containing Intermediate 2 (1.0 eq) and tert-butyl benzene solution at -40 °C. After completing the dropwise addition, the temperature was raised to 70 °C, and the mixture was stirred for 1 hour, and pentane was distilled off. After cooling to -40 °C, boron tribromide (3.0 eq) was added thereto, and the mixture was raised to room temperature and stirred for 1 hour. Thereafter, the mixture was again cooled to 0 °C, and N,N-diisopropylethylamine (3.0 eq) was added thereto and stirred at room temperature, and then stirred at 100 °C for 3 hours. The reaction solution was cooled to 0 °C and potassium acetate saturated solution and ethyl acetate were added thereto to separate the liquid layer. Then the solvent was removed by distillation under reduced pressure. It was purified by silica gel column chromatography (eluent: hexane / methylene chloride = 40 / 1 (volume / volume)) to obtain Compound BD-37; (yield: 41.96%).

[0164] The resulting compound BD-37 was subjected to detection analysis, and the results were as follows:

[0165] HPLC purity: >99.95%.

[0166] MS (ESI, m / Z): [M+H]+: 944.88.

[0167] Elemental analysis:

[0168] Calculated: C, 83.86; H, 8.64; N, 2.96; S, 3.39; B, 1.14.

[0169] Test: C, 83.43; H, 8.89; N, 3.21; S, 3.43; B, 1.20.

[0170] The synthesis of the compound of formula I is the same as the above examples, which will not be repeated here, and the mass spectrum, molecular formula and yield of other synthesis examples are shown in Table 1 below.

[0171] Table 1

[0172] Compound Molecular formula Mass calculated Mass found Yield (%) Compound 3 C54H35NO 713.27 713.35 65.98 Compound 8 C54H35NO 713.27 713.36 74.94 Compound 9 C54H35NO 713.27 713.4 70.68 Compound 10 C46H31NO 613.24 613.41 66.78 Compound 14 C50H33NO 663.26 663.45 77.74 Compound 18 C46H31NO 613.24 613.46 66.58 Compound 21 C54H35NO 713.27 713.36 70.55 Compound 25 C52H34N2O 702.27 702.45 68.88 Compound 33 C52H34N2O 702.27 702.37 73.06 Compound 37 C54H35NS 729.25 729.44 67.07 Compound 41 C54H35NS 729.25 729.39 69.28 Compound 47 C46H31NS 629.22 629.47 66.49 Compound 54 C46H31NS 629.22 629.39 68.02 Compound 59 C48H29NS2 683.17 683.34 72.7 Compound 64 C55H38N2S 758.28 758.45 77.37 Compound 72 C55H38N2S 758.28 758.38 71.1 Compound 78 C58H38N2S 794.28 794.35 77.71 Compound 82 C58H38N2O 778.30 778.57 69.82

[0173] The synthesis of the compound of formula II is the same as the above examples, which will not be repeated here, and the mass spectrum, molecular formula and yield of other synthesis examples are shown in Table 2 below.

[0174] Table 2

[0175]

[0176] [Application Example 1] Preparation of an organic electroluminescent device:

[0177] a. ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150 nm is cleaned in distilled water for 2 times, ultrasonic washing for 30 min, and then repeatedly cleaned with distilled water for 2 times, ultrasonic washing for 10 min. After washing, it is baked in a vacuum oven at 220°C for 2 hours, and then cooled to room temperature for use. The substrate is used as an anode, and a device process is performed by using an evaporation machine to evaporate other functional layers on it.

[0178] b. HIL (hole injection layer): The hole injection layer materials HT1-8 and P-9 are vacuum evaporated at an evaporation rate of , and the evaporation rate ratio of HT1-8 and P-9 is 97:3, and the thickness is 10 nm;

[0179] c. HTL (hole transport layer): The HT1-8 is vacuum evaporated on the hole injection layer as a hole transport layer at an evaporation rate of 130 nm;

[0180] d. Prime (second hole transport layer): The compound of formula I is vacuum evaporated on the hole transport layer as a second hole transport layer at an evaporation rate of 5 nm;

[0181] e. EML (emitting layer): Then, the second hole transport layer is evaporated on the above-mentioned second hole transport layer at an evaporation rate of BH-9 host material and the dopant of formula II were vacuum deposited at a thickness of 25 nm as the light-emitting layer, wherein the deposition rate ratio of the host material and the dopant of formula II was 97:3.

[0182] f、HB (hole blocking layer): the compound ET-7 was vacuum deposited at a thickness of 5.0 nm as the hole blocking layer. f、HB (hole blocking layer): the compound ET-7 was vacuum deposited at a thickness of 5.0 nm as the hole blocking layer.

[0183] g、ETL (electron transport layer): the compound ET-14 and Liq were vacuum deposited at a thickness of 30 nm as the electron transport layer, wherein the deposition rate ratio of ET and Liq was 50:50. g、ETL (electron transport layer): the compound ET-14 and Liq were vacuum deposited at a thickness of 30 nm as the electron transport layer, wherein the deposition rate ratio of ET and Liq was 50:50.

[0184] h、EIL (electron injection layer): Yb film was deposited at a thickness of 1.0 nm as the electron injection layer. h、EIL (electron injection layer): Yb film was deposited at a thickness of 1.0 nm as the electron injection layer.

[0185] i、cathode: Mg and Ag were deposited at a thickness of 13 nm as the cathode, wherein the deposition rate ratio of Mg and Ag was 1:9, thereby obtaining the OLED device. i、cathode: Mg and Ag were deposited at a thickness of 13 nm as the cathode, wherein the deposition rate ratio of Mg and Ag was 1:9, thereby obtaining the OLED device.

[0186] j、light extraction layer: CPL was vacuum deposited at a thickness of 70 nm on the cathode as the light extraction layer. j、light extraction layer: CPL was vacuum deposited at a thickness of 70 nm on the cathode as the light extraction layer.

[0187] k、the substrate after the deposition was encapsulated. First, the cleaned cover plate was coated with UV glue by using a gluing device, then the coated cover plate was moved to the pressing section, the substrate after the deposition was placed on the end of the cover plate, finally the substrate and the cover plate were adhered under the action of the adhering device, and the UV glue was simultaneously cured by light.

[0188] The compounds used in the device are as follows:

[0189]

[0190] Device Comparative Example:

[0191] The device comparative example provides an organic electroluminescent device, and the only difference between the preparation method of the organic electroluminescent device and the device embodiment 1 is that the organic electroluminescent device is prepared by vacuum depositing the second hole transport layer or the dopant material in the device embodiment 1 with the existing comparative compounds, respectively, wherein the chemical structural formula of the comparative compound related to the present application is as follows:

[0192]

[0193] The driving voltage, luminous efficiency and lifespan of the organic electroluminescent devices obtained from Examples 1-23 and Device Comparative Examples 1-19 above were characterized at a brightness of 1000 (nits), and the test results are shown in Table 3 below.

[0194] 1. Comparative Examples 1-4, Examples 1-9

[0195] The organic electroluminescent devices of Comparative Examples 1-4, Examples 1-9 were prepared according to the above preparation method of the organic electroluminescent device, and BD-1 was used as the dopant material, and the second hole transport material was selected from the compounds shown in Table 3.

[0196] 2. Comparative Examples 5-8, Examples 10-19

[0197] The organic electroluminescent devices of Comparative Examples 5-8, Examples 10-19 were prepared according to the above preparation method of the organic electroluminescent device, and BD-37 was used as the dopant material, and the second hole transport material was selected from the compounds shown in Table 3.

[0198] 3. Comparative Examples 9-12, Examples 20-23

[0199] The organic electroluminescent devices of Comparative Examples 9-12, Examples 20-23 were prepared according to the above preparation method of the organic electroluminescent device, and BD-38 was used as the dopant material, and the second hole transport material was selected from the compounds shown in Table 3.

[0200] 4. Comparative Examples 13-19

[0201] The organic electroluminescent devices of Comparative Examples 13-19 were prepared according to the above preparation method of the organic electroluminescent device, and the dopant material and the second hole transport material were selected from the corresponding compounds in Table 3, respectively.

[0202] The performance of the organic electroluminescent devices of the comparative examples and examples was determined, and the test results are shown in Table 3.

[0203] Table 3: Test results of luminescent properties (brightness value is 1000 nits)

[0204]

[0205]

[0206] Specifically, the overall drive voltage of the organic electroluminescent device of the present application is 3.43-3.58 V, the BI value is 190.1-203.9, and the lifetime is 489-513 h when BD-1 is used as the doping material; the drive voltage of Comparative Examples 1-4 is 3.63-3.70 V, the BI is 178.6-186.3, and the lifetime is 460-473 h. When BD-37 and BD-38 are used as the doping material, the overall drive voltage is 3.54-3.68 V, the BI value is 178.4-185.9, and the lifetime is 500-525 h; the drive voltage of Comparative Examples 5-12 is 3.69-3.75 V, the BI is 170.5-175.5, and the lifetime is 483-491 h. The drive voltage of Comparative Examples 13-19 prepared from Compound 1, Compound 2, Compound 4, Compound 5, Compound 47, Compound 59, and Compound 82 is 3.69-3.75 V, the BI is 158.4-162.5, and the lifetime is 358-378 h; it can be seen that the performance of the blue organic electroluminescent device prepared from the second hole transport material of Formula I and the doping material of Formula II is much higher than that of the comparative examples.

[0207] The applicant states that the organic electroluminescent device and the application thereof of the present application are illustrated by the above examples, but the present application is not limited to the above examples, i.e., it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. An organic electroluminescent device, characterized by comprising: The organic electroluminescent device comprises a first electrode, a second electrode facing the first electrode, a light-emitting layer between the first electrode and the second electrode, and a hole transport region between the first electrode and the light-emitting layer; The hole transport region comprises a compound represented by Formula I; X in Formula I is O or S; Ar is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthryl and phenanthryl, and Ar is fused and annulated with the adjacent benzene ring on the mother nucleus, and the fused position is 1,2, 2,3 or 3,4 of the benzene ring; L is selected from a bond or L is a bond when the N atom is directly attached to the phenyl ring; R3 is selected from any one of substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3-30 membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted 3-30 membered heteroaryl, and the heteroatoms in the heterocycloalkyl and heteroaryl are independently selected from oxygen, nitrogen or sulfur; R1 is selected from any one of hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3-30 membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted 3-30 membered heteroaryl, and the heteroatoms in the heterocycloalkyl and heteroaryl are independently selected from oxygen, nitrogen or sulfur; Ar1 and Ar2 are each independently selected from any one of substituted or unsubstituted 3-30 membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted 3-30 membered heteroaryl, and the heteroatoms in the heterocycloalkyl and heteroaryl are independently selected from oxygen, nitrogen or sulfur; The dopant material in the light-emitting layer is a compound represented by Formula II: In Formula II, R4 is selected from substituted or unsubstituted diarylamine, substituted or unsubstituted C1-C30 alkyl, and substituted or unsubstituted C6-C30 aryl. R a -R d each independently of one another, is selected from the group consisting of substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl; R4, R a R d each independently represents a mono-, di-, tri-, tetra-, penta-substituted or unsubstituted group; The substituents in the substituted groups in Formula I and Formula II are selected from any one or a combination of at least two of deuterium, C1-C30 alkyl or C6-C30 aryl.

2. The organic electroluminescent device according to claim 1, wherein L is selected from a linking bond or any one of the following groups: * represents the linking position of the group.

3. The organic electroluminescent device according to claim 1, wherein R1 is independently selected from hydrogen or any one of the following groups: * represents the linking position of the group.

4. The organic electroluminescent device according to claim 1, wherein Ar1 and Ar2 are the same as or different from each other and are each independently selected from one or a combination of several groups: * represents the linking position of the group.

5. The organic electroluminescent device according to claim 1, wherein R4is selected from the group consisting of diaromatic amine groups, formula II is selected from the group consisting of formulae II-1, R a R4is selected from the group consisting of substituted or unsubstituted C6-C30aryl groups, formula II is selected from the group consisting of formulae II-2:

6. The organic electroluminescent device according to claim 1, wherein The compound represented by Formula I is any one of the following compounds:

7. The organic electroluminescent device according to claim 1, wherein The compound represented by Formula II is any one of the following compounds:

8. The organic electroluminescent device according to claim 1, wherein The hole transport region at least comprises a hole injection layer, a first hole transport layer, and a second hole transport layer, and the second hole transport layer is a compound represented by Formula I.

9. A display panel, characterized by, The display panel comprises the organic electroluminescent device according to any one of claims 1-8.

10. Use of the organic electroluminescent device according to any one of claims 1-8 in an organic light-emitting device, an organic solar cell, electronic paper, an organic photoreceptor or an organic thin-film transistor.

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