Organic electroluminescent device and electronic device

Abstract

The application discloses an organic electroluminescent device and an electronic device, the organic electroluminescent device comprises a cathode, an anode and an organic layer formed between the cathode and the anode, the organic layer comprises a light-emitting layer, and a hole injection layer, a hole transport layer and a plurality of light-emitting auxiliary layers are sequentially arranged between the anode and the light-emitting layer, the light-emitting auxiliary layers comprise a first light-emitting auxiliary layer adjacent to the hole transport layer and a second light-emitting auxiliary layer adjacent to the light-emitting layer, wherein the refractive index of the first light-emitting auxiliary layer is lower than that of the second light-emitting auxiliary layer. The device adopts the design scheme of the multiple light-emitting auxiliary layers matched with different refractive index materials, optimizes the energy level transition between the organic layers of the device, smoothes the transmission path of the carriers, realizes the stepwise injection of the holes from the hole transport layer to the light-emitting layer, is favorable to improving the hole transport efficiency, and through the careful control of the refractive index, the light field distribution of the microcavity of the device is optimized, the light extraction efficiency is improved, and the device has a good application prospect.

Description

Technical Field

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

[0002] Organic electroluminescent devices typically consist of a cathode, an anode, and multiple organic film layers disposed between them. For devices containing corresponding organic 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 light is emitted when the excitons re-transition to the ground state.

[0003] In the field of organic electroluminescent technology, the luminous efficiency and lifetime of devices have always been the focus of industry attention. To improve the overall performance of organic electroluminescent devices, traditional improvement approaches mainly include two categories: one is developing novel organic functional materials, such as hole transport materials with high mobility; the other is optimizing the device structure, such as designing the hole transport layer as a multi-layer stacked structure, thereby allowing for more precise control of energy levels to improve the hole injection barrier. Based on this, the field has also gradually begun to focus on controlling the optical performance of the device's microcavity, such as improving the light extraction efficiency of the device by combining layers with different refractive indices. For example, invention documents such as CN102742352A ("Organic Electroluminescent Element and Lighting Device"), CN121865836A ("An Organic Electroluminescent Device"), and CN118830343A ("Composition, Organic Electroluminescent Element, and Electronic Device") all involve one or more of the above-mentioned aspects in their improvement strategies.

[0004] However, there is an urgent need in this field to develop more high-performance devices. Summary of the Invention

[0005] The present invention aims to provide a new design scheme to optimize organic electroluminescent devices in order to improve device performance.

[0006] The technical solution provided by this invention includes: An organic electroluminescent device includes a cathode, an anode, and an organic layer formed between the cathode and the anode. The organic layer includes a light-emitting layer, and a hole injection layer, a hole transport layer, and a plurality of light-emitting auxiliary layers sequentially disposed between the anode and the light-emitting layer. The device is characterized by: The light-emitting auxiliary layer includes a first light-emitting auxiliary layer and a second light-emitting auxiliary layer, wherein the first light-emitting auxiliary layer is adjacent to the hole transport layer, the second light-emitting auxiliary layer is adjacent to the light-emitting layer, and the material forming the first light-emitting auxiliary layer is selected from the compound shown in Formula 1, and the material forming the second light-emitting auxiliary layer is selected from the compound shown in Formula 2. Formula 1 In Equation 1: R1, R2, R3, R4, R5 and R6 represent deuterium, n is an integer selected from 0 to 5, m, j, k and q are each independently selected from 0 to 4, and p is an integer selected from 0 to 3; X represents a CR7R8 group, and R7 and R8 being the same or different indicates a C1-C4 alkyl group that is substituted with deuterium or unsubstituted. Ar1 is a C6-C20 aryl group that is substituted or unsubstituted, and the substituents of Ar1 are selected from deuterium, deuterated or unsubstituted C1-C4 alkyl groups. Formula 2 In Equation 2: R9 is a C1-C4 alkyl group that is either deuterated or unsubstituted; R 10 R 11 R 12 R 15 and R 16 Let represent deuterium, where s, t, i, and z are each independent integers selected from 0 to 4, and w is an integer selected from 0 to 3; Y represents CR 13 R 14 Group, R 13 and R 14 The same or different indicates C1-C4 alkyl groups that are deuterated or unsubstituted; Ar2 is a C5-C20 heteroaryl group that is substituted or unsubstituted, and the substituents of Ar2 are selected from deuterium, deuterium-substituted or unsubstituted C6-C12 aryl groups.

[0007] Based on the above scheme, a more preferred implementation scheme also includes: Furthermore, in Formulas 1 and 2, the deuterated or unsubstituted C1-C4 alkyl group is selected from the following deuterated or unsubstituted groups: methyl, ethyl, isopropyl, and tert-butyl.

[0008] Furthermore, in Formula 1, Ar1 is selected from substituted or unsubstituted biphenyl groups, and the substituents of Ar1 are deuterium, methyl, or deuterated methyl.

[0009] Furthermore, in Formula 2, Ar2 is selected from heteroaryl groups containing O or S heteroatoms, whether substituted or unsubstituted.

[0010] Furthermore, the material forming the first light-emitting auxiliary layer in this invention is selected from compounds shown in Formula 1-1: Equation 1-1 In Equation 1-1: R1, R2, R3, R4, R5, and R6 represent deuterium; n is an integer selected from 0 to 5, m, j, k and q are each independently selected from 0 to 4, and p is an integer selected from 0 to 3; The same or different R7 and R8 indicate methyl groups that are deuterated or unsubstituted; Ar1 is a biphenyl that is substituted or unsubstituted, and the substituents of Ar1 are selected from deuterated or unsubstituted methyl groups.

[0011] Furthermore, the material forming the second light-emitting auxiliary layer in this invention is selected from compounds shown in Formula 2-1: In Equation 2-1: R9 is a methyl group that is either deuterated or unsubstituted; R 10 R 11 R 12 R 15 and R 16 Let represent deuterium, where s, t, i, and z are each independently selected from integers from 0 to 4, and w is selected from integers from 0 to 3; R 13 and R 14 The terms "same" or "different" indicate whether the methyl group is deuterated or unsubstituted. Ar2 is dibenzofuran.

[0012] Furthermore, the material forming the first light-emitting auxiliary layer in this invention is selected from the following compounds: .

[0013] Furthermore, the material used to form the second light-emitting auxiliary layer in this invention is selected from the following compounds: .

[0014] Furthermore, the refractive index of the first light-emitting auxiliary layer material is lower than that of the second light-emitting auxiliary layer material, and the difference in refractive index between the first and second light-emitting auxiliary layers is not less than 0.02.

[0015] Furthermore, the refractive index of the first light-emitting auxiliary layer material is ≤1.80.

[0016] An electronic device, characterized in that it comprises an organic electroluminescent device as described in any of the preceding embodiments.

[0017] Beneficial effects: This invention relates to an organic electroluminescent device employing a multi-emissive auxiliary layer design. Between the hole transport layer and the auxiliary layer adjacent to the light-emitting layer, another auxiliary layer with a lower refractive index is introduced. On one hand, by incorporating compounds within a defined scope, the multi-emissive auxiliary layer design optimizes the energy level transition between the organic layers, smooths the carrier transport path, and enables a stepped injection of holes from the hole transport layer to the light-emitting layer, thus improving hole transport efficiency. On the other hand, by precisely controlling the refractive index, the internal light field distribution of the device is optimized, improving light extraction efficiency. Compared to existing technologies, this invention, through the synergistic cooperation of multiple auxiliary layers made of suitable materials, further improves the device's performance and has promising application prospects. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the organic electroluminescent device provided by the present invention; Figure 2 This is the HPLC spectrum of compound 1; Figure 3 This is the NMR spectrum of compound 1; Figure 4 This is the HPLC spectrum of compound 17; Figure 5 This is the NMR spectrum of compound 17.

[0019] Figure 1 The reference numerals in the figures represent: 1-anode, 2-hole injection layer, 3-hole transport layer, 4-first light-emitting auxiliary layer, 5-second light-emitting auxiliary layer, 6-light-emitting layer, 7-hole blocking layer, 8-electron transport layer, 9-electron injection layer, and 10-cathode. Detailed Implementation

[0020] 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.

[0021] In this document, the terms "substituted" and "unsubstituted" refer to the recoordination of at least one hydrogen atom of a group with a substituent group such as deuterium, alkyl, aryl, or heteroaryl. "Aryl" in this document refers to a group containing one or more aromatic rings, including but not limited to benzene, naphthalene, phenanthrene, fluorene, and acenaphthene. "Heteroaryl" in this document refers to a heteroaryl group obtained by substituting one or more carbon atoms in the structure of an "aryl" group with one or more heteroatoms (such as N, O, or S), including but not limited to pyridine, pyrimidine, pyrrole, furan, thiophene, dibenzofuran, dibenzothiophene, and carbazole.

[0022] The terms C6-C20, C5-C20, C1C4, and C6-C12 in the text indicate that the modified groups contain 6-20, 5-20, 14, and 6-12 carbon atoms, respectively. If the corresponding groups can be substituted, C6-C20, C5-C20, C1C4, and C6-C12 here do not include the number of carbon atoms of the substituents.

[0023] In this invention, "deuterium" refers to a stable isotope of hydrogen, also known as heavy hydrogen, and its element symbol is D.

[0024] Unless otherwise specified in the following synthesis examples, the synthesis should be carried out under standard conditions or the manufacturer's recommended conditions. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0025] I. Material Synthesis 1. Synthesis of the first light-emitting auxiliary layer material 1.1. Synthesis of Compound 17 1) Synthetic route ; .

[0026] 2) Synthesis steps S1: Under nitrogen protection, compound 17-a (1 eq, 20 g, 162.02 g / mol, 0.1234 mol) and ultradry THF (200 ml) were added to a reaction flask. The temperature was lowered to below -65°C, and n-butyllithium (1.05 eq, 51.8 ml, 2.5 mol / L, 0.1296 mol) was added dropwise. After the addition was complete, the mixture was kept at this temperature and stirred for 1 h. Then, ultradry THF (87 ml) containing 17-b (0.95 eq, 21.7 g, 185.02 g / mol, 0.1172 mol) was added dropwise, keeping the internal temperature below -60°C. After the addition was complete, the mixture was moved to room temperature and stirred for 1 h. Finally, saturated ammonium chloride aqueous solution (300 ml) was added. The mixture was stirred and quenched in 200 ml of water, separated, and the aqueous phase was extracted with DCM (200 ml). The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to dryness to obtain compound 17-c (32.7 g), which was used directly in the next reaction without purification.

[0027] S2: Under nitrogen protection, compound 17-c (1 eq, theoretical 31.42 g, 268.09 g / mol, 0.1172 mol), potassium carbonate (3 eq, 48.6 g, 138.21 g / mol, 0.3516 mol), iodine (1.6 eq, 47.6 g, 253.81 g / mol, 0.1875 mol) and tert-butanol (300 ml) were added to a reaction flask. The mixture was heated to 95 °C and stirred for 5 h. After the reaction was completed, the mixture was cooled to room temperature and quenched with 50% sodium thiosulfate (300 ml). The mixture was then filtered, the filter cake was washed with water, and dried at 65 °C with forced air to obtain compound 17-d (24.7 g, two-step yield 79.2%).

[0028] S3: Under nitrogen protection, compound 17-e (1 eq, 22.78 g, 233.11 g / mol, 0.097715 mol) and ultradry THF (200 ml) were added to a reaction flask. The mixture was cooled to below -65°C, and n-butyllithium (1.05 eq, 41 ml, 2.5 mol / L, 0.1026 mol) was added dropwise. After the addition was complete, the mixture was kept at this temperature and stirred for 1 h. Then, ultradry THF (75 ml) of 17-d (0.95 eq, 24.7 g, 266.08 g / mol, 0.09283 mol) was added dropwise, keeping the internal temperature below -60°C. After the addition was complete, the mixture was moved to room temperature and stirred for 1 h. A saturated ammonium chloride aqueous solution (200 ml) was added and stirred to quench the reaction. The mixture was separated, and the aqueous phase was extracted with DCM (200 ml). The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to dryness to obtain compound 17-f (42... g), without purification, is used directly in the next reaction.

[0029] S4: Compound 17-f (1 eq, 39 g, 420.29 g / mol, 0.09283 mol) and DCM (400 ml) were added to a reaction flask and cooled to below 0 °C. Methanesulfonic acid (2.5 eq, 22.3 g, 96.1 g / mol, 0.2321 mol) was added dropwise. After the addition was complete, the mixture was moved to room temperature and stirred for 1 h. After the reaction was complete, ethanol (400 ml) was added. After 400 ml of solvent was distilled off under normal pressure, the mixture was cooled to room temperature and stirred to crystallize for 1 h. The mixture was filtered, and the filter cake was recrystallized twice with DCM / ethanol and dried in a forced-air environment at 85 °C to obtain compound 17-g (30.3 g, yield 81.2%).

[0030] S5: Under nitrogen protection, compound 17-g (1 eq, 30.3 g, 402.27 g / mol, 75.32 mmol), compound 17-h (1 eq, 27.23 g, 361.49 g / mol, 75.32 mmol), sodium tert-butoxide (1.5 eq, 10.86 g, 96.1 g / mol, 112.98 mmol), 10% tritert-tert-butylphosphine toluene solution (0.04 eq, 6.1 ml, 202.32 g / mol, 3.0128 mmol), tris(dibenzylacetone)palladium (0.02 eq, 1.38 g, 915.7 g / mol, 1.5064 mmol), and toluene (300 mg / mL) were mixed. Add (mL) to the reaction flask. After the addition is complete, heat to 110℃ and stir for 3 hours. After the reaction is complete, filter while hot through silica gel. Wash the filter cake with dichloromethane. Concentrate the filtrate under reduced pressure to dryness. Add toluene (200ml) and heat to dissolve. Add ethanol (400ml) and cool to room temperature for 2 hours to crystallize. The filtered solid is recrystallized twice with toluene (200ml) + ethanol (400ml). The filtered solid is dried at 85℃ to give compound 17 (38.2g, yield 74.3%). ESI-MS (m / z, [M+H)) + Theoretical value: 683.35; Measured value: 683.39.

[0031] 1.2. Synthesis of Compound 22 ; .

[0032] Following the same synthetic route as compound 17, compound 22 was obtained (79% yield) by the reaction. ESI-MS (m / z, [M+H]) + Theoretical value: 697.37, measured value: 697.38.

[0033] 1.3. Synthesis of Compound 24 ; .

[0034] Following the same synthetic route as compound 17, compound 24 was obtained (yield 70.2%). ESI-MS (m / z, [M+H]) was performed. + Theoretical value: 697.37, measured value: 697.39.

[0035] 1.4. Synthesis of Compound 1 .

[0036] Following the preparation method described in the final step of compound 17, and taking the above synthetic route, compound 1 was obtained (yield 76.5%). ESI-MS (m / z, [M+H]) + Theoretical value: 678.32, measured value: 678.36. Compound 1-a can be synthesized by directly purchasing raw materials or by referring to the synthesis example described above.

[0037] 1.5. Synthesis of Compound 6 .

[0038] Following the preparation method of the last step of compound 17, and according to the above synthetic route, compound 6 was obtained (yield 78.1%). ESI-MS (m / z, [M+H]) + Theoretical value: 692.33, measured value: 692.39. Compound 6-a can be synthesized by directly purchasing raw materials or by referring to the synthesis example described above.

[0039] 1.6 Synthesis of other compounds Other compounds used in the first luminescent auxiliary layer can be prepared by referring to the preparation method of compound 17, and will not be listed here one by one.

[0040] 2. Synthesis of the second light-emitting auxiliary layer 2.1. Synthesis of Compound 127 1) Synthetic route ; .

[0041] 2) Synthesis steps S1: Under nitrogen protection, compound 127-a (1 eq, 20 g, 195.42 g / mol, 102.34 mmol) and ultra-dry THF (200 mL) were added to a reaction flask. The mixture was cooled to below -65 °C, and n-butyllithium (1.05 eq, 43 mL, 2.5 mol / L, 107.46 mmol) was added dropwise. After the addition was complete, the mixture was kept at this temperature and stirred for 1 h. Then, 127-b (0.95 eq, 17.52 g, 180.21 mmol) was added dropwise. Add 88 ml of ultradry THF (g / mol, 97.22 mmol) and control the internal temperature to not exceed -60 °C. After the addition is complete, move to room temperature and stir for 1 h. After the reaction is complete, add 300 ml of saturated ammonium chloride aqueous solution and stir to quench. Separate the liquid and extract the aqueous phase with dichloromethane (200 ml). Combine the organic phases, dry with anhydrous sodium sulfate, and concentrate to dryness to obtain compound 127-c (32.7 g, over-yield). Without purification, it is used directly in the next reaction.

[0042] S2: Under nitrogen protection, compound 127-c (1 eq, theoretical 28.85 g, 296.73 g / mol, 97.22 mmol), triethylsilane (1.5 eq, 16.96 g, 116.28 g / mol, 145.83 mmol), and dichloromethane (300 ml) were added to a reaction flask. The mixture was cooled to -10 °C, and trifluoroacetic acid (3 eq, 33.26 g, 114.02 g / mol, 291.66 mmol) was added dropwise. After the addition was complete, the mixture was moved to room temperature and reacted for 3 h. After the reaction was complete, the mixture was concentrated to dryness, and n-heptane (200 ml) was added and stirred for 2 h. A solid precipitated, which was filtered. The filter cake was washed with water and dried at 65 °C with forced air to obtain compound 127-d (23.33 g, two-step yield 85.5%).

[0043] S3: Under nitrogen protection, compound 127-d (1 eq, 23.33 g, 280.73 g / mol, 83.1 mmol) and ultradry THF (200 mL) were added to a reaction flask. The mixture was cooled to below -20 °C, and 60% sodium hydride (3 eq, 10 g, 24 g / mol, 249.31 mmol) was added dropwise. After the addition was complete, the mixture was heated to 45 °C and reacted for 1 h. The mixture was then cooled to below -20 °C, and deuterated iodomethane (1.5 eq, 18.07 g, 144.96 g / mol, 124.66 mmol) was added dropwise. After the first addition of mmol, the mixture was moved to room temperature and stirred for 1 hour. After the reaction was complete, the temperature was lowered to below -10°C, and water (500 ml) was slowly added dropwise until no more bubbles were generated. The mixture was separated, and the aqueous phase was extracted once with dichloromethane (250 ml). The organic phases were combined and concentrated to dryness. Heptane (200 ml) was added and stirred to induce crystallization. The mixture was filtered, and the filter cake was dried at 65°C with a forced air to obtain compound 127-e (21.4 g, yield 86.5%).

[0044] S4: Under nitrogen protection, compound 127-e (1 eq, 21.4 g, 297.72 g / mol, 71.88 mmol), compound 127-f (1 eq, 13.17 g, 183.21 g / mol, 71.88 mmol), sodium tert-butoxide (1.5 eq, 10.36 g, 96.1 g / mol, 107.82 mmol), 10% tritert-tert-butylphosphine toluene solution (0.04 eq, 5.8 ml, 202.32 g / mol, 2.88 mmol), tris(dibenzylacetone)palladium (0.02 eq, 1.32 g, 915.7 g / mol, 1.44 mmol), and toluene (200 mg / mL) were mixed. Add ethanol (mL) to the reaction flask. After the addition is complete, heat to 110℃ and stir for 3 hours. After the reaction is complete, filter the mixture through silica gel while hot. Wash the filter cake with toluene. Concentrate the filtrate under reduced pressure to dryness. Add ethanol (200 mL), heat to dissolve, cool to room temperature and stir to crystallize for 1 hour. Filter the mixture and dry the filter cake at 85℃ to obtain compound 127-g (24.54 g, yield 76.8%).

[0045] S5: Under nitrogen protection, compound 127-g (1 eq, 24.54 g, 444.48 g / mol, 55.21 mmol), compound 127-h (1 eq, 15.41 g, 279.2 g / mol, 55.21 mmol), sodium tert-butoxide (1.5 eq, 7.96 g, 96.1 g / mol, 82.82 mmol), 10% tritert-tert-butylphosphine toluene solution (0.04 eq, 4.5 ml, 202.32 g / mol, 2.21 mmol), tris(dibenzylacetone)palladium (0.02 eq, 1.01 g, 915.7 g / mol, 1.1 mmol), and toluene (250 mg / mL) were mixed. Add mL of the mixture to the reaction flask. After the addition is complete, heat to 110℃ and stir for 3 hours. After the reaction is complete, filter the mixture while hot through silica gel. Wash the filter cake with dichloromethane. Concentrate the filtrate under reduced pressure to dryness. Add toluene (100 mL) and heat to dissolve the solid. Add ethanol (400 mL) and cool to room temperature for 2 hours to allow crystallization. Recrystallize the filtered solid twice with toluene (50 mL) + ethanol (200 mL). Dry the filtered solid at 85℃ to obtain compound 127 (24.45 g, yield 68.9%). ESI-MS (m / z, [M+H)) + Theoretical value: 643.36, measured value: 643.38.

[0046] 2.2. Synthesis of Compound 126 ; .

[0047] Following the same synthetic route as compound 127, compound 126 was obtained (72.4% yield) by the reaction. ESI-MS (m / z, [M+H]) + Theoretical value: 637.33, measured value: 637.30.

[0048] 2.3 Synthesis of other compounds Other compounds used for the second luminescent auxiliary layer can be prepared by referring to the preparation method of compound 127, and will not be listed here one by one.

[0049] II. Device Testing 1. Application Examples 1.1. Application Example 1 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 hole injection layer (HIL) was formed by depositing 10 nm of HT1 doped with 5% NDP-9 on top of the ITO / Ag / ITO anode substrate. A hole transport layer (HTL) is formed by vacuum evaporating 100 nm of HT1 above the hole injection layer (HIL); A first light-emitting auxiliary layer (GPL) is formed by vacuum evaporating 20 nm of the low-refractive-index compound 1 of the present invention above the hole transport layer (HTL); A second light-emitting auxiliary layer (GPL') is formed by vacuum evaporating 20 nm of the high-refractive-index compound 125 of the present invention above the first light-emitting auxiliary layer (GPL); GH-1 and GH-2 were used as the main light-emitting materials (the mass ratio of GH-1 and GH-2 was 5:5), and GD-1 was used as the light-emitting dopant (the amount of GD-1 was 4% of the total weight of GH-1 and GH-2). They were co-deposited on the second light-emitting auxiliary layer (GPL') to form a light-emitting layer (EML) with a thickness of 40 nm. HB-1 was deposited onto the light-emitting layer (EML) 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 an electron transport layer (ETL) with a thickness of 30 nm. Ytterbium (Yb) is vapor-deposited onto the electron transport layer (ETL) to form an electron injection layer (EIL) with a thickness of 1 nm; Magnesium (Mg) and silver (Ag) are mixed in a mass ratio of 1:9 and vapor-deposited onto the electron injection layer (EIL) to form a cathode with a thickness of 12 nm. A CP-1 layer with a thickness of 60 nm is deposited on the cathode sealing layer 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 the influence of oxygen or moisture in the atmosphere. Thus, an organic electroluminescent device is prepared.

[0050] 1.2. Application Example 2-5 With all other conditions the same as in Application Example 1, compound 1 in the first light-emitting auxiliary layer was replaced with 6, 17, 22 and 24 respectively, thereby obtaining the organic electroluminescent devices of Application Examples 2-5.

[0051] 1.3. Application Examples 6-9 With all other conditions the same as in Application Example 1, compound 1 in the first light-emitting auxiliary layer was replaced with compound 17, and compound 125 in the second light-emitting auxiliary layer was replaced with 126, 127, 128 and 129, respectively, thereby obtaining the organic electroluminescent devices of Application Examples 6-9.

[0052] 1.4. Application Examples 10-12 With all other conditions the same as in Application Example 1, compound 1 in the first light-emitting auxiliary layer was replaced with compound 22, and compound 125 in the second light-emitting auxiliary layer was replaced with 130, 131 and 132, respectively, thereby obtaining the organic electroluminescent devices of Application Examples 10-12.

[0053] In addition to the compounds of this invention, other compounds involved in the test systems of the above application examples are shown in Table 1 below: Table 1 2. Comparative Example 2.1. Comparative Examples 1-4 With all other conditions being the same as in Application Example 1, the first and second light-emitting auxiliary layers made of different materials in Application Example 1 were replaced with the entire light-emitting auxiliary layer made of single compounds 1, 17, 125 and 129, respectively, thereby obtaining organic electroluminescent devices of Comparative Examples 1-4.

[0054] 2.3. Comparative Example 5 With all other conditions consistent with Application Example 1, the material combination scheme provided in the patent document with publication number CN114725301A was introduced, and the material of the first light-emitting auxiliary layer was replaced with D-1, and the material of the second light-emitting auxiliary layer was replaced with D-1', as shown in Table 2 below, thereby obtaining Comparative Example 5.

[0055] Table 2 At a current density of 10 mA / cm 2 Under the specified conditions, the operating characteristics of the organic electroluminescent devices prepared in each application example and comparative example were tested, including key parameters such as start-up voltage, luminous efficiency, and luminous lifetime. The test results are shown in Tables 3 and 4 below: Table 3 In Table 4, the T97% data refers to the relative time it takes for the device's luminance to decrease to 97% of its initial luminance. The test results are based on the device lifetime data of Comparative Example 2. Table 4 The devices of the present invention are provided with two Prime material layers, namely a first light-emitting auxiliary layer and a second light-emitting auxiliary layer. The refractive index of the material of the first light-emitting auxiliary layer is lower than that of the second light-emitting auxiliary layer. Specifically, in the above application example, the refractive index of the material of the first light-emitting auxiliary layer is ≤1.80, and the difference between the refractive index of the first light-emitting auxiliary layer and the refractive index of the second light-emitting auxiliary layer is not less than 0.02.

[0056] The test data above shows that, compared with devices using a single material for the light-emitting auxiliary layer, or with devices containing a combination of materials provided by existing technologies, the device in this invention exhibits better performance in terms of parameters such as voltage, luminous efficiency, and luminous lifetime. This includes a trend towards lower voltage, higher luminous efficiency, and longer luminous lifetime, thus verifying that the solution provided by this invention has a significant optimization effect on device performance and has promising application prospects.

[0057] 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 a cathode, an anode, and an organic layer formed between the cathode and the anode, said organic layer comprising a light-emitting layer, and a hole injection layer, a hole transport layer, and a plurality of light-emitting auxiliary layers sequentially disposed between the anode and the light-emitting layer, characterized in that: The light-emitting auxiliary layer includes a first light-emitting auxiliary layer and a second light-emitting auxiliary layer, wherein the first light-emitting auxiliary layer is adjacent to the hole transport layer, and the second light-emitting auxiliary layer is adjacent to the light-emitting layer. The refractive index of the material of the first light-emitting auxiliary layer is lower than that of the material of the second light-emitting auxiliary layer, and the difference in refractive index between the two materials is not less than 0.

02. The material forming the first light-emitting auxiliary layer is selected from compounds shown in Formula 1, and the material forming the second light-emitting auxiliary layer is selected from compounds shown in Formula 2. Formula 1 ； In Equation 1: R1, R2, R3, R4, R5 and R6 represent deuterium, n is an integer selected from 0 to 5, m, j, k and q are each independently selected from 0 to 4, and p is an integer selected from 0 to 3; X represents the CR7R8 group, and R7 and R8 being the same or different indicates a C1-C4 alkyl group that is substituted with deuterium or unsubstituted. Ar1 is a C6-C20 aryl group that is substituted or unsubstituted, and the substituents of Ar1 are selected from deuterium, deuterium-substituted or unsubstituted C1-C4 alkyl groups. Formula 2 ； In Equation 2: R9 is a C1-C4 alkyl group that is either deuterated or unsubstituted; R 10 R 11 R 12 R 15 and R 16 Let denot deuterium, where s, t, i, and z are each independent integers selected from 0 to 4, and w is an integer selected from 0 to 3; Y represents CR 13 R 14 Group, R 13 and R 14 The same or different indicates C1-C4 alkyl groups that are deuterated or unsubstituted; Ar2 is a C5-C20 heteroaryl group that is substituted or unsubstituted, and the substituents of Ar2 are selected from deuterium, deuterium-substituted or unsubstituted C6-C12 aryl groups.

2. The organic electroluminescent device as described in claim 1, characterized in that, In Formulas 1 and 2, the deuterium-substituted or unsubstituted C1-C4 alkyl group is selected from the following deuterium-substituted or unsubstituted groups: Methyl, ethyl, isopropyl, and tert-butyl.

3. The organic electroluminescent device as described in claim 1, characterized in that, In Formula 1, Ar1 is selected from substituted or unsubstituted biphenyl groups, and the substituents of Ar1 are deuterium, methyl or deuterated methyl.

4. An organic electroluminescent device as described in claim 1, characterized in that, In Formula 2, Ar2 is selected from heteroaryl groups containing O or S heteroatoms, whether substituted or unsubstituted.

5. An organic electroluminescent device as described in claim 1, characterized in that, The material forming the first light-emitting auxiliary layer is selected from compounds shown in Formula 1-1: Equation 1-1 ； In Equation 1-1: R1, R2, R3, R4, R5, and R6 represent deuterium; n is an integer selected from 0 to 5, m, j, k and q are each independently selected from 0 to 4, and p is an integer selected from 0 to 3; The same or different R7 and R8 indicate methyl groups that are deuterated or unsubstituted; Ar1 is a biphenyl that is substituted or unsubstituted, and the substituents of Ar1 are selected from deuterium, deuterated or unsubstituted methyl groups.

6. An organic electroluminescent device as described in claim 1, characterized in that, The material forming the second light-emitting auxiliary layer is selected from compounds shown in Formula 2-1: ； In Equation 2-1: R9 is a methyl group that is either deuterated or unsubstituted; R 10 R 11 R 12 R 15 and R 16 Let represent deuterium, where s, t, i, and z are each independently selected from integers from 0 to 4, and w is selected from integers from 0 to 3; R 13 and R 14 The same or different indicates a methyl group that is deuterated or unsubstituted; Ar2 is dibenzofuran.

7. An organic electroluminescent device as described in claim 1, characterized in that, The material forming the first light-emitting auxiliary layer is selected from the following compounds: 。 8. An organic electroluminescent device as described in claim 1, characterized in that, The material forming the second light-emitting auxiliary layer is selected from the following compounds: 。 9. An organic electroluminescent device as described in claim 1, characterized in that, The refractive index of the first light-emitting auxiliary layer material is ≤1.

80.

10. An electronic device, characterized in that, The organic electroluminescent device includes any one of claims 1-9.

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