An organic electroluminescence device and a light emitting apparatus

Abstract

This invention discloses an organic electroluminescent device and a light-emitting apparatus. The electroluminescent device has two hole transport layers arranged in a high-low refractive index relationship near the anode side. The material of the first hole transport layer is shown in Equation 1, and the material of the second hole transport layer is shown in Equation 2. This invention, through optimization of the combination of film materials and the structural combination of films with different refractive indices, ensures both material stability and carrier transport. Simultaneously, by optimizing the optical microcavity structure, it improves the light field distribution, enhances the photon extraction efficiency of the device, and reduces the ineffective loss of photon energy within the organic layers. This results in improved performance in the organic electroluminescent device and the light-emitting apparatus containing it, in terms of luminous efficiency, start-up voltage, and luminous lifetime. (Equations 1 and 2 are referenced.)

Description

Technical Field

[0001] This invention belongs to the field of electroluminescence technology, specifically an organic electroluminescent device and light-emitting apparatus. Background Technology

[0002] Organic electroluminescent displays typically refer to devices such as OLEDs that use electric current to drive organic film layers to achieve the effect of emitting light, thereby realizing the purpose of display.

[0003] Organic electroluminescent devices consist of a cathode, an anode, and multiple organic film layers disposed between them, such as a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer. In devices containing these film layers, when a voltage is applied between the two electrodes, holes are injected into the organic layer from the anode, and electrons are injected into the organic layer from the cathode. When holes and electrons meet, excitons are formed, and when the excitons re-transition to the ground state, light is emitted.

[0004] In the field of organic electroluminescence technology, the luminous efficiency of light-emitting devices has always been a focus of industry attention. The luminous efficiency of these devices is affected by various electrical and optical factors, such as: electrical factors including exciton generation efficiency, carrier injection, transport, and balance design; and optical factors including material spectral properties, optical microcavity structure, and photon extraction efficiency. Furthermore, in organic electroluminescence devices, due to the presence of organic layers and metal electrodes, photons generated by the light-emitting layer are easily confined within the organic layer, forming waveguide modes, or coupled to the metal / organic interface to excite surface plasmon polaritons, resulting in energy loss as heat dissipation and making it difficult to effectively extract energy from the device.

[0005] The above factors collectively affect the luminous efficiency of organic electroluminescent devices. Changes in device materials or structure may have either positive or negative effects on these factors. Therefore, achieving a comprehensive improvement in device performance through material selection and structural design is challenging. Summary of the Invention

[0006] The technical objective of this invention is to design an improved solution that optimizes the material combination and structural composition of organic electroluminescent devices from both optoelectronic perspectives, thereby enhancing device performance.

[0007] The technical solution provided by this invention includes the following aspects:

[0008] In a first aspect, the present invention provides an organic electroluminescent device, comprising an anode, a cathode, and a light-emitting layer formed between the anode and the cathode, wherein a hole injection layer and a hole transport region are provided between the anode and the light-emitting layer closest to the anode, and the hole transport region includes a first hole transport layer, a second hole transport layer, and a third hole transport layer, wherein the material of the first hole transport layer is selected from the compound shown in Formula 1, the material of the second hole transport layer is selected from the compound shown in Formula 2, and the refractive index of the material of the first hole transport layer is greater than the refractive index of the material of the second hole transport layer;

[0009] Formula 1

[0010] ;

[0011] In Formula 1, rings A, B, E, F, G, and H are each independently selected from substituted or unsubstituted C6-C18 aryl groups, wherein the C6-C18 aryl group comprises phenyl, biphenyl, and fused ring groups formed by the fusion of no more than three cyclic groups, and the substituents of the C6-C18 aryl group are selected from deuterium, phenyl, and naphthyl.

[0012]

Formula 2

[0013] ;

[0014] In Equation 2, R1-R 31 Each is independently selected from hydrogen, deuterium, deuterated or unsubstituted C1-C4 alkyl groups, and,

[0015] The number of groups selected from C1-C4 alkyl groups that are simultaneously substituted with deuterium or unsubstituted in R1-R9 is ≤3;

[0016] R 10 -R 24 The number of groups simultaneously selected from C1-C4 alkyl groups that are either deuterated or unsubstituted is ≤4;

[0017] R 25 -R 31 The number of groups selected simultaneously from C1-C4 alkyl groups that are either deuterated or unsubstituted is ≤3.

[0018] Based on the above solutions, further improvements include:

[0019] Preferably, R1-R9 contain at least one C1-C4 alkyl group that is either deuterated or unsubstituted.

[0020] Preferably, the material of the hole injection layer comprises a first compound and a second compound with different structures, wherein the first compound is selected from compounds shown in Formula 1 or Formula 2, and the second compound is a dopant with a mass less than 5% of the mass of the first compound.

[0021] Preferably, the first compound of the hole injection layer is the same as the compound selected for the first hole transport layer or the second hole transport layer.

[0022] Preferably, in Formula 1, the A ring, B ring, E ring, F ring, G ring, and H ring are each independently selected from the group types shown in Formulas (a) to (j):

[0023]

[0024] In this context, * indicates a connection site.

[0025] Preferably, the compounds selected from Formula 1 have the same or partially the same structure for their A, B, E, F, G, and H rings, and contain no more than three types of functional groups.

[0026] Preferably, the material forming the first hole transport layer is selected from any of the following compounds:

[0027] .

[0028] Preferably, in Formula 2, the C1-C4 alkyl group that is substituted or unsubstituted with deuterium comprises methyl, isopropyl, tert-butyl, and deuterated methyl.

[0029] In R1-R9, all R1-R9 are hydrogen, and one or two of R1-R3, R5 and R9 are selected from C1-C4 alkyl groups that are substituted with deuterium or not substituted, and the rest are hydrogen.

[0030] R 10 -R 24 In the middle, R 10 -R 24 All are hydrogen, or R 10 -R 18 R 21 -R 24 One to three of them are selected from C1-C4 alkyl groups that are substituted with deuterium or unsubstituted, and the remainder are hydrogen or deuterium;

[0031] R 25 -R 31 In the middle, R 25 -R 31 All are hydrogen, or R 25 R 28 R 30 R 31 One or two of them are selected from C1-C4 alkyl groups that are substituted with deuterium or not, and the rest are hydrogen.

[0032] Preferably, the material forming the second hole transport layer is selected from any of the following compounds:

[0033] .

[0034] Furthermore, the organic electroluminescent device of the present invention is characterized in that a hole injection layer, a first hole transport layer, a second hole transport layer, a third hole transport layer, one or more light-emitting layers, a hole blocking layer, an electron transport layer and an electron injection layer are arranged sequentially between the anode and the cathode.

[0035] In a second aspect, the present invention provides a light-emitting device, characterized in that it comprises an organic electroluminescent device as described in any of the preceding claims.

[0036] The beneficial effects of this invention are as follows:

[0037] The organic electroluminescent device and light-emitting apparatus of the present invention optimize the combination of film materials and the structural combination of film layers with different refractive indices, which not only ensures the stability of materials and the transport of charge carriers, but also improves the light field distribution by optimizing the optical microcavity structure, thereby improving the photon extraction efficiency of the device and reducing the ineffective loss of photon energy inside the organic layer. This enables the organic electroluminescent device and the light-emitting apparatus containing the device to achieve performance improvements in luminous efficiency, start-up voltage and luminous lifetime. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the organic electroluminescent device provided by the present invention;

[0039] Figure 1 The reference numerals in the figures represent: 1-anode, 2-hole injection layer, 3-first hole transport layer, 4-second hole transport layer, 5-third hole transport layer, 6-first light-emitting layer, 7-second light-emitting layer, 8-hole blocking layer, 9-electron transport layer, 10-electron injection layer, 11-cathode, 12-light extraction layer. Detailed Implementation

[0040] Embodiments of various aspects of the invention are further described and illustrated below. It should be understood that the following description is not intended to limit the claims to the specific aspects described. Rather, it is intended to cover substitutions, modifications, and equivalents that may be included within the scope defined by the appended claims.

[0041] In the text, the term "substituted or unsubstituted" refers to the recoordination of at least one hydrogen atom of a group with a substituent group such as deuterium, alkyl, or aryl. "Aryl" refers to a group containing one or more aromatic rings, which, unless otherwise specified, includes, but is not limited to, benzene, naphthalene, phenanthrene, fluorene, and acenaphthene.

[0042] The terms C6-C18 and C1-C4 in the text indicate that the modified group contains 6-18 and 1-4 carbon atoms, respectively. If the corresponding group can be substituted, the terms C6-C18 and C1-C4 here do not need to include the number of carbon atoms of the substituent.

[0043] In this invention, "deuterium" refers to an isotope of hydrogen (H), also known as heavy hydrogen, and its corresponding element symbol is D.

[0044] The following describes the implementation scheme of the present invention and verifies the advancement of the design scheme in more detail with the synthesis and testing of materials. For the corresponding embodiments, if specific conditions are not specified, they shall be carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased commercially.

[0045] I. Synthesis of HTL1 material

[0046] 1. Synthesis of Compound 1

[0047] 1.1. Synthetic Route

[0048] ;

[0049] 1.2. Synthesis Process

[0050] S1: Under nitrogen protection, compounds 1-a (1 eq, 36.18 g, 361.8 g / mol, 0.1 mol), 1-b (1 eq, 16.92 g, 169.23 g / mol, 0.1 mol), sodium tert-butoxide (1.5 eq, 14.42 g, 96.1 g / mol, 0.15 mol), DPPF (0.04 eq, 2.22 g, 554.38 g / mol, 0.004 mol), tris(dibenzylacetone)palladium (0.02 eq, 1.83 g, 915.7 g / mol, 0.002 mol), and toluene (300 μL) were added. The solution was added to the reaction flask in mL. After the addition was complete, the temperature was raised to 110℃ and the mixture was stirred for 3 h. After the reaction was complete, the mixture was filtered through silica gel while hot. The filter cake was washed with dichloromethane, and the filtrate was concentrated to dryness under reduced pressure. Ethanol (200 mL) was added, and the mixture was stirred to induce crystallization for 2 h. The resulting gray solid was filtered and dried at 85℃ to give compound 1-c (32.2 g, yield 79.9%). MS (m / z): 401.95 ([M+H)). + );

[0051] S2: Under nitrogen protection, compounds 1-c (1 eq, 32.2 g, 403.12 g / mol, 79.9 mmol), 1-b (2.05 eq, 27.72 g, 169.23 g / mol, 163.8 mmol), sodium tert-butoxide (2.5 eq, 19.2 g, 96.1 g / mol, 0.2 mol), 10% tri-tert-butylphosphine toluene solution (0.04 eq, 6.5 ml, 202.32 g / mol, 3.196 mmol), tris(dibenzylacetone)palladium (0.02 eq, 1.46 g, 915.7 g / mol, 1.598 mmol), and toluene (300 mL) were mixed. The solution was added to a reaction flask (mL), and after the addition was complete, the temperature was raised to 110℃ and the mixture was stirred for 6 hours. After the reaction was complete, the mixture was filtered through silica gel while hot. The filter cake was washed with dichloromethane, and the filtrate was concentrated to dryness under reduced pressure. Toluene (150 mL) was added and heated to dissolve the solid, followed by the addition of ethanol (150 mL). The mixture was cooled to room temperature and allowed to crystallize for 2 hours. The filtered solid was recrystallized twice with toluene (150 mL). The filtered solid was dried at 85℃ to give compound 1 (24.23 g, yield 52.3%). ESI-MS (m / z, [M+H)) + Theoretical value: 580.28, measured value: 580.30. Elemental analysis results (molecular formula C42H33N3): Theoretical value: C, 87.01; H, 5.74; N, 7.25; Measured value: C, 87.03; H, 5.75; N, 7.22.

[0052] 2. Synthesis of Compound 2

[0053] 2.1. Synthetic Route

[0054] ;

[0055] 2.2. Synthesis Process

[0056] Compound 2 was prepared using a similar method to compound 1 (yield 54%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 630.29, measured value: 630.28. Elemental analysis results (molecular formula C46H35N3): Theoretical value: C, 87.73; H, 5.60; N, 6.67; Measured value: C, 87.72; H, 5.58; N, 6.70.

[0057] 3. Synthesis of Compound 3

[0058] 3.1. Synthetic Route

[0059] ;

[0060] 3.2. Synthesis Process

[0061] Compound 3 was prepared using a similar method to that used for compound 1 (yield 53.3%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 630.29, measured value: 630.26. Elemental analysis results (molecular formula C46H35N3): Theoretical value: C, 87.73; H, 5.60; N, 6.67; Measured value: C, 87.74; H, 5.61; N, 6.62.

[0062] 4. Synthesis of Compound 4

[0063] 4.1. Synthetic Route

[0064] ;

[0065] 4.2. Synthesis Process

[0066] Compound 4 was prepared by a similar method to that used for compound 1 (yield 49.8%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 680.31, measured value: 680.34. Elemental analysis results (molecular formula C50H37N3): Theoretical value: C, 88.33; H, 5.49; N, 6.18; Measured value: C, 88.34; H, 5.5; N, 6.16.

[0067] 5. Synthesis of Compound 5

[0068] 5.1. Synthetic Route

[0069] ;

[0070] 5.2. Synthesis Process

[0071] Compound 5 was prepared using a similar method to that used for compound 1 (yield 50.5%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 680.31, measured value: 680.36. Elemental analysis results (molecular formula C50H37N3): Theoretical value: C, 88.33; H, 5.49; N, 6.18; Measured value: C, 88.30; H, 5.51; N, 6.19.

[0072] 6. Synthesis of Compound 7

[0073] 6.1. Synthetic Route

[0074] ;

[0075] 6.2. Synthesis Process

[0076] Compound 7 was prepared using a similar method to that used for compound 1 (yield 55.3%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 730.32, measured value: 730.35. Elemental analysis results (molecular formula C54H39N3): Theoretical value: C, 88.86; H, 5.39; N, 5.76; Measured value: C, 88.88; H, 5.40; N, 5.72.

[0077] 7. Synthesis of Compound 8

[0078] 7.1. Synthetic Route

[0079] ;

[0080] 7.2. Synthesis Process

[0081] Compound 8 was prepared using a similar method to that used for compound 1 (yield 61.3%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 730.32, measured value: 730.36. Elemental analysis results (molecular formula C54H39N3): Theoretical value: C, 88.86; H, 5.39; N, 5.76; Measured value: C, 88.85; H, 5.38; N, 5.77.

[0082] 8. Synthesis of Compound 9

[0083] 8.1. Synthetic Route

[0084] ;

[0085] 8.2. Synthesis Process

[0086] Compound 9 was prepared using a similar method to that used for compound 1 (yield 60.7%). ESI-MS (m / z, [M+H]) yielded the compound. + Theoretical value: 730.32, measured value: 730.30. Elemental analysis results (molecular formula C54H39N3): Theoretical value: C, 88.86; H, 5.39; N, 5.76; Measured value: C, 88.89; H, 5.40; N, 5.72.

[0087] 9. Synthesis of Compound 10

[0088] 9.1. Synthetic Route

[0089] ;

[0090] 9.2. Synthesis Process

[0091] Compound 10 was prepared using a similar method to that used for compound 1 (yield 55.2%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 730.32, measured value: 730.29. Elemental analysis results (molecular formula C54H39N3): Theoretical value: C, 88.86; H, 5.39; N, 5.76; Measured value: C, 88.83; H, 5.32; N, 5.82.

[0092] 10. Synthesis of Compound 18

[0093] 10.1. Synthetic Route

[0094] ;

[0095] 10.2. Synthesis Process

[0096] Compound 18 was prepared by a similar method to that used for compound 1 (yield 60.1%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 732.34, measured value: 732.28. Elemental analysis results (molecular formula C54H41N3): Theoretical value: C, 88.61; H, 5.65; N, 5.74; Measured value: C, 88.63; H, 5.66; N, 5.72.

[0097] 11. Synthesis of Compound 21

[0098] 11.1. Synthetic Route

[0099] ;

[0100] 11.2. Synthesis Process

[0101] Under nitrogen protection, compounds 21-a (1 eq, 25.2 g, 314.80 g / mol, 79.9 mmol), 21-b (3.1 eq, 60.77 g, 245.32 g / mol, 247.7 mmol), sodium tert-butoxide (2.5 eq, 19.2 g, 96.1 g / mol, 0.2 mol), 10% tritert-tert-butylphosphine toluene solution (0.04 eq, 6.5 ml, 202.32 g / mol, 3.196 mmol), tris(dibenzylacetone)palladium (0.02 eq, 1.46 g, 915.7 g / mol, 1.598 mmol), and toluene (300 mL) were mixed. The compound was added to a reaction flask in mL. After the addition was complete, the temperature was raised to 110℃ and the mixture was stirred for 6 h. After the reaction was complete, the mixture was filtered through silica gel while hot. The filter cake was washed with dichloromethane, and the filtrate was concentrated to dryness under reduced pressure. Toluene (150 mL) was added and heated to dissolve the solid. Then, ethanol (150 mL) was added, and the mixture was cooled to room temperature to crystallize for 2 h. The filtered solid was recrystallized twice with toluene (150 mL). The filtered solid was dried at 85℃ to give compound 21 (42.35 g, yield 65.6%). ESI-MS (m / z, [M+H)) + Theoretical value: 808.37, measured value: 808.39. Elemental analysis results (molecular formula C60H45N3): Theoretical value: C, 89.19; H, 5.20; N, 5.61; Measured value: C, 89.16; H, 5.21; N, 5.63.

[0102] Compounds 1, 7, and 10 can also be prepared by referring to the synthetic route of compound 21 to simplify the process.

[0103] 2. HTL2 material synthesis

[0104] 12. Synthesis of Compound 101

[0105] 12.1. Synthetic Route

[0106] ;

[0107] 12.2. Synthesis Process

[0108] S1: Under nitrogen protection, compound 101-a (1 eq, 27.32 g, 273.17 g / mol, 0.1 mol), compound 101-b (1 eq, 18.33 g, 183.25 g / mol, 0.1 mol), sodium tert-butoxide (1.5 eq, 14.42 g, 96.1 g / mol, 0.15 mol), 10% tri-tert-butylphosphine toluene solution (0.04 eq, 8.1 ml, 202.32 g / mol, 0.004 mol), tris(dibenzylacetone)palladium (0.02 eq, 1.83 g, 915.7 g / mol, 0.002 mol), and toluene (300 mL) were mixed. The solution was added to the reaction flask in mL. After the addition was complete, the temperature was raised to 110℃ and the mixture was stirred for 6 h. After the reaction was complete, the mixture was filtered through silica gel while hot. The filter cake was washed with dichloromethane, and the filtrate was concentrated to dryness under reduced pressure. Ethanol (150 mL) was added, and the mixture was heated to 80℃ and stirred until dissolved. The mixture was then cooled to room temperature to crystallize for 5 h. The resulting gray solid was filtered and dried at 85℃ to give compound 101-c (28.5 g, yield 75.9%). MS (m / z): 376.21 ([M+H)). + ).

[0109] S2: Under nitrogen protection, compound 101-c (1 eq, 28.5 g, 375.51 g / mol, 75.9 mmol), compound 1-b (1 eq, 30 g, 395.3 g / mol, 75.9 mmol), sodium tert-butoxide (1.5 eq, 10.94 g, 96.1 g / mol, 0.114 mol), 10% tri-tert-butylphosphine toluene solution (0.04 eq, 6.1 ml, 202.32 g / mol, 3.036 mmol), tris(dibenzylacetone)palladium (0.02 eq, 1.39 g, 915.7 g / mol, 1.518 mmol), and toluene (300 mL) were mixed. The solution was added to a reaction flask (mL), and after the addition was complete, the temperature was raised to 110℃ and the mixture was stirred for 6 hours. After the reaction was complete, the mixture was filtered through silica gel while hot. The filter cake was washed with dichloromethane, and the filtrate was concentrated to dryness under reduced pressure. Toluene (150 mL) was added and heated to dissolve the solid. Then, ethanol (150 mL) was added, and the mixture was cooled to room temperature to crystallize for 2 hours. The filtered solid was recrystallized twice with toluene (150 mL) + ethanol (150 mL). The filtered solid was then recrystallized twice with toluene (75 mL). The resulting solid was dried at 85℃ to give compound 101 (31.2 g, yield 59.6%). ESI-MS (m / z, [M+H)) +Theoretical value: 690.32, measured value: 690.33. Elemental analysis results (molecular formula C53H39N): Theoretical value: C, 92.27; H, 5.70; N, 2.03; Measured value: C, 92.29; H, 5.69; N, 2.02.

[0110] 2. Synthesis of Compound 109

[0111] 2.1. Synthetic Route

[0112] ;

[0113] 2.2. Synthesis Process

[0114] Compound 109 was prepared using a similar method to that used for compound 101 (yield 60.3%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 802.44, measured value: 802.45. Elemental analysis results (molecular formula C61H55N): Theoretical value: C, 91.34; H, 6.91; N, 1.75; Measured value: C, 91.30; H, 6.94; N, 1.76.

[0115] 3. Synthesis of Compound 110

[0116] 3.1. Synthetic Route

[0117] ;

[0118] 3.2. Synthesis Process

[0119] Compound 110 was prepared using a similar method to that used for compound 101 (yield 62.3%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 802.44, measured value: 802.45. Elemental analysis results (molecular formula C61H55N): Theoretical value: C, 91.34; H, 6.91; N, 1.75; Measured value: C, 91.30; H, 6.94; N, 1.79.

[0120] 4. Synthesis of Compound 119

[0121] 4.1. Synthetic Route

[0122] ;

[0123] 4.2. Synthesis Process

[0124] Compound 119 was prepared using a similar method to that used for compound 101 (61% yield). ESI-MS (m / z, [M+H]) yielded

[119] . +Theoretical value: 746.38, measured value: 746.39. Elemental analysis results (molecular formula C57H47N): Theoretical value: C, 91.77; H, 6.35; N, 1.88; Measured value: C, 91.75; H, 6.36; N, 1.89.

[0125] 5. Synthesis of Compound 125

[0126] 5.1. Synthetic Route

[0127] ;

[0128] 5.2. Synthesis Process

[0129] Compound 125 was prepared using a similar method to that used for compound 101 (yield 58.2%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 690.32, measured value: 690.30. Elemental analysis results (molecular formula C53H39N): Theoretical value: C, 92.27; H, 5.70; N, 2.03; Measured value: C, 92.23; H, 5.74; N, 2.03.

[0130] 6. Synthesis of Compound 126

[0131] 6.1. Synthetic Route

[0132] ;

[0133] 6.2. Synthesis Process

[0134] Compound 126 was prepared by a similar method to that used for compound 101 (yield 60.1%). ESI-MS (m / z) ([M+H) + Theoretical value: 718.35, measured value: 718.28. Elemental analysis results (molecular formula C55H43N): Theoretical value: C, 92.05; H, 6.00; N, 1.95; Measured value: C, 92.10; H, 5.89; N, 2.01.

[0135] 7. Synthesis of Compound 129

[0136] 7.1. Synthetic Route

[0137] ;

[0138] 7.2. Synthesis Process

[0139] Compound 129 was prepared using a similar method to that used for compound 101 (yield 60.5%). ESI-MS (m / z, [M+H]) was performed. +Theoretical value: 704.33, measured value: 704.29. Elemental analysis results (molecular formula C54H41N): Theoretical value: C, 92.14; H, 5.87; N, 1.99; Measured value: C, 92.11; H, 5.88; N, 2.01.

[0140] 8. Synthesis of Compound 133

[0141] 8.1. Synthetic Route

[0142] ;

[0143] 8.2. Synthesis Process

[0144] Compound 133 was prepared using a similar method to that used for compound 101 (yield 59.8%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 816.46, measured value: 816.45. Elemental analysis results (molecular formula C62H57N): Theoretical value: C, 91.24; H, 7.04; N, 1.72; Measured value: C, 91.7; H, 7.07; N, 1.73.

[0145] 9. Synthesis of Compound 142

[0146] 9.1. Synthetic Route

[0147] ;

[0148] 9.2. Synthesis Process

[0149] Compound 142 was prepared using a similar method to that used for compound 101 (yield 65.1%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 844.49, measured value: 844.50. Elemental analysis results (molecular formula C64H61N): Theoretical value: C, 91.06; H, 7.28; N, 1.66; Measured value: C, 91.07; H, 7.30; N, 1.63.

[0150] III. Device Fabrication

[0151] (1) Application example preparation

[0152] 1. Application Example 1

[0153] ITO / Ag / ITO was used as the anode substrate material for the reflective layer, and its surface was treated sequentially with water, acetone, and N2 plasma. A 10 nm layer of compound 1 doped with 3% NDP-9 was deposited on top of the ITO / Ag / ITO anode substrate to form a hole injection layer (HIL). A 46 nm layer of compound 1 was vacuum-deposited on top of the hole injection layer (HIL) to form a first hole transport layer (HTL1). A 52 nm layer of compound 101 was vacuum-deposited on top of the first hole transport layer (HTL1) to form a second hole transport layer (HTL2). EB-1 was vacuum-deposited on top of the second hole transport layer (HTL2) to form a third hole transport layer (EBL) with a thickness of 10 nm. BH-1 was used as the host material and BD-1 as the dopant material (BD-1 doping ratio was 1% of the host material BH-1) were co-deposited to form a first emitting layer (EML1) with a thickness of 5 nm on the third hole transport layer (EBL). BH-2 was used as the host material and BD-1 as the dopant material (BD-1 doping ratio was 2% of the host material BH-2) were co-deposited to form a second emitting layer (EML2) with a thickness of 15 nm on the first emitting layer (EML1). HB-1 was deposited onto the second emitting layer (EML2) to obtain a hole blocking layer (HBL) with a thickness of 5 nm. ET-1 and LiQ were co-deposited onto the hole blocking layer (HBL) at a mass ratio of 5:5 to obtain a layer with a thickness of 30 nm. An electron transport layer (ETL) is formed; ytterbium (Yb) is deposited onto the ETL to form an electron injection layer (EIL) with a thickness of 1 nm; magnesium (Mg) and silver (Ag) are mixed in a 1:9 mass ratio and deposited onto the EIL to form a cathode with a thickness of 12 nm; a 60 nm thick CP-2 layer is deposited at the sealing layer of the cathode to form a light extraction layer (CPL); finally, the device surface is sealed with a UV-curable adhesive and a sealing film containing a desiccant to protect the organic electroluminescent device from atmospheric oxygen or moisture. This completes the fabrication of the organic electroluminescent device.

[0154] 2. Application Example 2

[0155] Based on Application Example 1, compound 1 in the hole injection layer was replaced with compound 101, and the organic electroluminescent device of Application Example 2 was prepared under the same preparation conditions as Application Example 1.

[0156] 3. Application Example 3

[0157] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 7, and the organic electroluminescent device of Application Example 3 was prepared under the same preparation conditions as Application Example 1.

[0158] 4. Application Example 4

[0159] Based on Application Example 1, compound 1 in the hole injection layer was replaced with compound 101, and compound 101 in the first hole transport layer was replaced with compound 7. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 4 was prepared.

[0160] 5. Application Example 5

[0161] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 21. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 5 was prepared.

[0162] 6. Application Example 6

[0163] Based on Application Example 1, compound 101 in the second hole transport layer was replaced with compound 109, and the organic electroluminescent device of Application Example 6 was prepared under the same preparation conditions as Application Example 1.

[0164] 7. Application Example 7

[0165] Based on Application Example 1, compound 1 in the hole injection layer was replaced with compound 109, compound 1 in the first hole transport layer was replaced with 7, and compound 101 in the second hole transport layer was replaced with compound 109. With other preparation conditions being the same as in Application Example 1, the organic electroluminescent device of Application Example 7 was prepared.

[0166] 8. Application Example 8

[0167] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 21, and compound 101 in the second hole transport layer was replaced with compound 109. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 8 was prepared.

[0168] 9. Application Example 9

[0169] Based on Application Example 1, compound 1 in the hole injection layer was replaced with compound 109, compound 1 in the first hole transport layer was replaced with compound 21, and compound 101 in the second hole transport layer was replaced with compound 109. With other preparation conditions being the same as in Application Example 1, the organic electroluminescent device of Application Example 9 was prepared.

[0170] 10. Application Example 10

[0171] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 2, and compound 101 in the second hole transport layer was replaced with compound 110. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 10 was prepared.

[0172] 11. Application Example 11

[0173] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 3, and compound 101 in the second hole transport layer was replaced with compound 110. With other preparation conditions being the same as in Application Example 1, the organic electroluminescent device of Application Example 11 was prepared.

[0174] 12. Application Example 12

[0175] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 4, and compound 101 in the second hole transport layer was replaced with compound 126. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 12 was prepared.

[0176] 13. Application Example 13

[0177] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 5, and compound 101 in the second hole transport layer was replaced with compound 126. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 13 was prepared.

[0178] 14. Application Example 14

[0179] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 7, and compound 101 in the second hole transport layer was replaced with compound 125. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 14 was prepared.

[0180] 15. Application Example 15

[0181] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 8, and compound 101 in the second hole transport layer was replaced with compound 125. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 12 was prepared.

[0182] 16. Application Example 16

[0183] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 9, and compound 101 in the second hole transport layer was replaced with compound 119. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 16 was prepared.

[0184] 17. Application Example 17

[0185] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 10, and compound 101 in the second hole transport layer was replaced with compound 129. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 17 was prepared.

[0186] 18. Application Example 18

[0187] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 18, and compound 101 in the second hole transport layer was replaced with compound 133. Under the same preparation conditions as Application Example 1, the organic electroluminescent device of Application Example 18 was prepared.

[0188] 19. Application Example 19

[0189] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 21, and compound 101 in the second hole transport layer was replaced with compound 142. With other preparation conditions being the same as in Application Example 1, the organic electroluminescent device of Application Example 19 was prepared.

[0190] 20. Application Example 20

[0191] Based on Application Example 1, compound 1 in the hole injection layer and the first hole transport layer was replaced with compound 21, and compound 101 in the second hole transport layer was replaced with compound 110. With other preparation conditions the same as in Application Example 1, an organic electroluminescent device of Application Example 20 was prepared.

[0192] (2) Comparative preparation

[0193] 1. Comparative Example 1

[0194] A hole transport layer with a thickness of 98 nm was deposited using compound 1 to replace the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 1. Under the same conditions as Application Example 1, an organic electroluminescent device of Comparative Example 1 was prepared.

[0195] 2. Comparative Example 2

[0196] An organic electroluminescent device of Comparative Example 2 was prepared by depositing a hole transport layer with a thickness of 98 nm using compound 101 instead of the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 1, under the same conditions as Application Example 1.

[0197] 3. Comparative Example 3

[0198] Organic electroluminescent devices of Comparative Example 3 were prepared by depositing a hole transport layer with a thickness of 98 nm using Compound 1 instead of the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 2, under the same conditions as Application Example 2.

[0199] 4. Comparative Example 4

[0200] An organic electroluminescent device of Comparative Example 4 was prepared by depositing a hole transport layer with a thickness of 98 nm using compound 101 instead of the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 2, under the same conditions as Application Example 2.

[0201] 5. Comparative Example 5

[0202] An organic electroluminescent device of Comparative Example 5 was prepared by depositing a hole transport layer with a thickness of 98 nm using compound 21 instead of the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 8, under the same conditions as Application Example 8.

[0203] 6. Comparative Example 6

[0204] An organic electroluminescent device of Comparative Example 6 was prepared by depositing a hole transport layer with a thickness of 98 nm using compound 109 instead of the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 8, under the same conditions as Application Example 8.

[0205] 7. Comparative Example 7

[0206] An organic electroluminescent device of Comparative Example 7 was prepared by depositing a hole transport layer with a thickness of 98 nm using compound 21 instead of the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 9, under the same conditions as Application Example 9.

[0207] 8. Comparative Example 8

[0208] An organic electroluminescent device of Comparative Example 9 was prepared by depositing a hole transport layer with a thickness of 98 nm using compound 109 instead of the first hole transport layer (HTL1) and the second hole transport layer (HTL2) in Application Example 1, under the same conditions as Application Example 9.

[0209] In addition to the compounds proposed in this invention, the structures of other compounds used in the above preparation process are as follows:

[0210]

[0211] IV. Device Testing

[0212] The characteristics of the organic electroluminescent devices prepared in Comparative Examples 1-8 and Application Examples 1-20 were tested respectively, including the start-up voltage, luminous efficiency and luminous lifetime. The luminous lifetime was T97% data (the relative time ratio of the device luminous brightness to 97% of the initial brightness, with Comparative Example 2 as the reference).

[0213] The test results are shown in Table 1 below:

[0214] Table 1

[0215]

[0216] The test data above shows that, within the scope of the compounds defined in this invention, compared to devices where the first and second hole transport layers are formed using a single material, the application example device, which replaces the first hole transport layer with a material of higher refractive index, exhibits a significant increase in luminous efficiency, a significant decrease in device startup voltage, reduced power consumption, and a longer luminous lifetime in the tests. This demonstrates that through material matching and structural optimization, the overall device performance can be improved.

[0217] In this invention, the NDP-9 content in the hole injection layer can generally be controlled to be below 5% of the mass of the hole injection layer bulk material, preferably a doping ratio of 1%-3%.

[0218] In the structural design of the hole transport layer (HTL) in this invention, the refractive index of the first hole transport layer is higher than that of the second hole transport layer. The first hole transport layer is made of an aromatic amine material based on three nitrogen atoms. The multi-nitrogen structure endows the material with high hole mobility and good electrochemical stability, which is beneficial to efficient hole injection and transport. The second hole transport layer is made of an aromatic amine material based on a single nitrogen atom and with large steric hindrance. The introduction of steric hindrance can effectively suppress the close packing between molecules, reduce the tendency to crystallize, and thus improve the film uniformity and thermal stability.

[0219] In the above test, the refractive index is the value at a wavelength of 460nm. As a more preferred embodiment of the present invention, a specific compound combination can be matched according to the scheme of "the refractive index of the first hole transport layer - the refractive index of the second hole transport layer ≥ 0.06".

[0220] This invention effectively controls the optical field distribution inside the device by optimizing the combination of hole transport layer materials and optical structure without affecting carrier transport performance and material stability, thereby reducing ineffective photon loss, improving the overall light extraction efficiency of the device, and giving the device a lower start-up voltage and better luminescence lifetime.

[0221] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An organic electroluminescent device, comprising an anode, a cathode, and a light-emitting layer formed between the anode and the cathode, wherein a hole injection layer and a hole transport region are provided between the anode and the light-emitting layer closest to the anode, characterized in that: The hole transport region includes a first hole transport layer and a second hole transport layer. The material of the first hole transport layer is selected from the compound shown in Formula 1, and the material of the second hole transport layer is selected from the compound shown in Formula 2. The refractive index of the material of the first hole transport layer is greater than the refractive index of the material of the second hole transport layer. Formula 1; In Formula 1, rings A, B, E, F, G, and H are each independently selected from substituted or unsubstituted C6-C18 aryl groups, wherein the C6-C18 aryl group comprises phenyl, biphenyl, and fused ring groups formed by the fusion of no more than three cyclic groups, and the substituents of the C6-C18 aryl group are selected from one or more of deuterium, phenyl, and naphthyl. Formula 2; In Formula 2, R1-R 31 each independently is selected from the group consisting of hydrogen, deuterium, C1-C4 alkyl substituted with deuterium or unsubstituted, and, The number of groups selected from C1-C4 alkyl groups that are either deuterated or unsubstituted in R1-R9 is ≤3; R 10 -R 24 R is selected from the group consisting of deuterium or unsubstituted C1-C4alkyl in an amount ≦4; R 25 -R 31 The number of groups selected from C1-C4 alkyl groups, substituted or not with deuterium, is ≦3.

2. The organic electroluminescent device according to claim 1, wherein R1-R9 contain at least one C1-C4 alkyl group that is either deuterated or unsubstituted.

3. The organic electroluminescent device as described in claim 1, characterized in that, The hole injection layer is made of a first compound and a second compound with different structures, wherein the first compound is selected from compounds shown in Formula 1 or Formula 2, and the second compound is a dopant with a mass less than 5% of the mass of the first compound.

4. The organic electroluminescent device as described in claim 3, characterized in that, The first compound of the hole injection layer is the same as the compound selected for the first hole transport layer or the second hole transport layer.

5. The organic electroluminescent device as described in claim 1, characterized in that, In Formula 1, the A ring, B ring, E ring, F ring, G ring, and H ring are each independently selected from the group types shown in Formulas (a) to (j): ； In this context, * indicates a connection site.

6. The organic electroluminescent device as described in claim 4, characterized in that, Among the compounds selected from Formula 1, the structures of their A ring, B ring, E ring, F ring, G ring and H ring are the same or partially the same, and the number of group types contained does not exceed three.

7. The organic electroluminescent device as described in claim 1, characterized in that, The compound shown in Formula 1 is selected from any one of the following compounds: 。 8. The organic electroluminescent device as described in claim 1, characterized in that, In Formula 2, the C1-C4 alkyl group that is substituted or unsubstituted with deuterium includes methyl, isopropyl, tert-butyl and deuterated methyl; In R1-R9, all of R1-R9 are hydrogen, or one or two of R1-R3, R5 and R9 are selected from C1-C4 alkyl groups that are substituted with deuterium or not substituted, and the rest are hydrogen; R 10 -R 24 wherein R 10 -R 24 are each hydrogen, or R 10 -R 18 , R 21 -R 24 1 to 4 of which are selected from C1-C4alkyl substituted with deuterium or unsubstituted, and the remainder are hydrogen or deuterium; R 25 -R 31 wherein R 25 -R 31 are each hydrogen, or R 25 , R 28 , R 30 , R 31 1 to 2 of which are selected from C1-C4alkyl substituted with deuterium or unsubstituted, and the remainder are hydrogen.

9. The organic electroluminescent device as described in claim 1, characterized in that, The compound shown in Formula 2 is selected from any one of the following compounds: 。 10. The organic electroluminescent device according to any one of claims 1-9, characterized in that, Between the anode and the cathode are arranged sequentially a hole injection layer, a first hole transport layer, a second hole transport layer, a third hole transport layer, one or more light-emitting layers, a hole blocking layer, an electron transport layer, and an electron injection layer.

11. A light-emitting device, characterized in that, The organic electroluminescent device includes any one of claims 1-9.

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