A spiroimidazole compound for organic electroluminescent devices

Abstract

The present invention discloses a spiroimidazole compound for use in organic electroluminescent devices, belonging to the technical field of organic electroluminescent materials. This compound, which uses a spiroimidazole derivative as a parent core and is modified with a group, exhibits superior frontier orbital energy levels and triplet energy. Application of this compound as a red light-emitting host material in organic electroluminescent devices can significantly improve the performance of the devices, increasing their luminous efficiency and service life. Compared to existing OLED devices, OLED devices whose light-emitting layers contain the spiroimidazole compound of the present invention as a red light-emitting host material have luminous efficiency increased by 15.2-41.6%, and device life extended by 15.3-56.2%.

Description

Technical Field

[0001] The invention belongs to the technical field of organic electroluminescent materials and relates to a spiroimidazole compound used for an organic electroluminescent device. Background Art

[0002] Organic electroluminescent devices (OLEDs) are current-type organic light-emitting devices (OLEDs). They offer advantages such as high efficiency, low power consumption, high contrast, thinness, and flexibility, making them widely used in display and lighting applications. Under the influence of an applied electric field, the physical process within the device is as follows: holes are injected from the anode into the organic layer, while electrons are injected from the cathode. When these injected holes and electrons meet in the light-emitting layer, they combine to form excitons. When the excitons transition back to their ground state, they release energy, which is emitted as light, creating the luminescent effect.

[0003] Exciton quenching refers to the phenomenon in which excitons lose energy prematurely during the luminescence process due to various reasons (such as interactions with impurities, defects, or other excitons), resulting in reduced luminescence efficiency. To further improve the optoelectronic properties of OLED devices, such as efficiency, brightness, and lifespan, existing technologies typically dope luminescent materials into specific host materials to reduce exciton quenching and optimize the device's luminescence performance. Because increasing the concentration of luminescent materials increases the probability of non-radiative transitions, which in turn reduces luminescence efficiency, doping luminescent materials into host materials can disperse excitons, optimize molecular stacking, and enhance reverse intersystem crossing, thereby reducing exciton quenching and improving the device's optoelectronic performance.

[0004] For phosphorescent devices, the host material not only needs to have good carrier transport properties to ensure that holes and electrons can be efficiently injected into the light-emitting layer, but also needs to have a high triplet energy to avoid exciton energy backtransfer. However, how to develop high-quality host materials that meet the above requirements and have good stability has always been a difficult and hot issue in the field of OLED technology. At present, although some host materials have been developed and applied to OLED devices, they still have certain limitations in performance and cannot meet the growing demand for higher quality OLED devices. Therefore, developing a high-performance host material is crucial to obtaining high-quality OLED devices. Summary of the Invention

[0005] To address the above technical issues, the present invention provides a spiroimidazole compound for use in organic electroluminescent devices. This compound, based on a spiro derivative as a core, is modified with a group to produce a spiroimidazole compound with superior frontier orbital energy levels and triplet state energies. Its application as a red-emitting host material in organic electroluminescent devices plays a key role in improving device performance, such as luminous efficiency and service life.

[0006] To achieve the technical purpose of the present invention, on the one hand, the present invention provides a spiroimidazole compound having a structure as shown in formula (I),

[0007] ;

[0008] X in the formula (I) is one of CR3R4, NR5, O, S, and Se;

[0009] R1 and R2 in the formula (I) are independently selected from one of hydrogen, deuterium, cyano, substituted or unsubstituted amino derivatives, C6-C30 aryl, and heteroaryl;

[0010] L1 and L2 in the formula (I) are independently selected from a single bond, an aryl group, and a heteroaryl group;

[0011] Ar1 and Ar2 in the formula (I) are independently selected from hydrogen, an amino derivative, a substituted or unsubstituted C6-C30 aryl group, and a heteroaryl group.

[0012] Furthermore, R3 and R4 in the CR3R4 are independently selected from one of a methyl group and a phenyl group; and R5 in the NR5 is one of a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted heteroaryl group.

[0013] Furthermore, the heteroaryl group contains at least one heteroatom, and the heteroatom in the heteroaryl group is selected from N, O, and S atoms; the heteroaryl group includes carbazolyl, furyl, acridinyl, fluorenyl, thienyl, triazine, pyrimidinyl, pyrazinyl, phenazinyl, pyridyl, benzimidazolyl, and phenanthroline.

[0014] Furthermore, when R1 and R2 are C6-C30 aryl groups, they are selected from any one of phenyl, biphenyl, and naphthyl. When Ar1 and Ar2 are substituted or unsubstituted C6-C30 aryl groups, they are selected from any one of phenyl, biphenyl, naphthyl, phenanthrenyl, and triphenylenyl.

[0015] Preferably, any of the above substituted or unsubstituted groups is as follows:

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[0027] Furthermore, the spiroimidazole compounds provided by the present invention have the structures shown as A1 to A5,

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[0029] Specifically, A1 to A5 have the following structures:

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[0076] On the other hand, the present invention seeks to protect the use of the above-mentioned spiroimidazole compounds in organic electroluminescent devices, wherein the compounds are used as red light-emitting host materials in the light-emitting layer of the organic electroluminescent device.

[0077] Furthermore, the spiroimidazole compounds of the present invention have relatively good frontier orbital energy levels and triplet energy, and are used as the main material of the light-emitting layer in red organic electroluminescent devices, which have a relatively good effect of improving the efficiency and life of the devices.

[0078] Specifically, the present invention applies the prepared spiroimidazole compound as the red light host material to the OLED device, which has better performance than the existing OLED devices, with the luminous efficiency increased by 15.2~41.6% and the device life extended by 15.3~56.2%.

[0079] On the other hand, the present invention seeks to protect an organic electroluminescent device comprising a light-emitting layer, wherein the host material of the light-emitting layer comprises the above-mentioned spiroimidazole compound.

[0080] Furthermore, the present invention seeks to protect a display assembly comprising the above-mentioned organic electroluminescent device.

[0081] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0082] (1) The compound prepared by the present invention is based on spiroimidazole as the core, and after the introduction of specific groups for modification, a compound with high mobility and high thermal stability is obtained. The present invention makes full use of the polarity of the heteroatoms in spiroimidazole and the molecular distortion of the compound to improve the carrier mobility of the compound and the triplet energy of the material and the glass transition temperature. On this basis, it is further modified with typical electron-donating groups such as amino, carbazole, acridinium or typical electron-withdrawing groups such as triazine and pyrimidine to optimize the frontier orbital energy level and triplet energy of the compound, thereby meeting the application of red light host materials and achieving high efficiency and long life of the device. The present invention simulates and calculates the physicochemical properties of spiroimidazole compounds and finds that the compound has relatively suitable HOMO, LUMO, and T1 values, and is suitable for use as a red light host material. When applied to OLED devices, it can effectively improve the luminous efficiency and service life of the device.

[0083] (2) The spiroimidazole compounds prepared by the present invention can be applied as the main material of the light-emitting layer in organic electroluminescent devices, significantly improving the efficiency, lifespan and other performance of the organic electroluminescent devices. The present invention applies the spiroimidazole compounds prepared by the present invention as the red light main material to OLED devices, which has better performance than the existing OLED devices, with the luminous efficiency increased by 15.2~41.6% and the device life extended by 15.3~56.2%. Compared with the comparative example, the luminous efficiency and service life of the device are significantly improved when the partially deuterated compound 171 is used as the first red light main material, with the luminous efficiency increased by 41.6% and the device life increased by 53.8%. Compared with the comparative example, the luminous efficiency of the device is increased by 28.9% and the device life is increased by 55.3% when the compound 79 is used as the second red light main material. When the partially deuterated compound 179 and the partially deuterated compound 164 are used as the first red light main material and the second red light main material, respectively, the luminous efficiency of the device is increased by 39.3% and the device life is increased by 56.2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention.

[0085] Figure 1 Schematic diagram of the structure of an organic electroluminescent device. 1 is the substrate, 2 is the anode layer, 3 is the hole injection layer, 4 is the first hole transport layer, 5 is the second hole transport layer, 6 is the light-emitting layer, 7 is the hole blocking layer, 8 is the electron transport layer, 9 is the electron injection layer, and 10 is the cathode layer. DETAILED DESCRIPTION

[0086] The following examples illustrate the technical solutions of the present invention, but the present invention is not limited to the following examples. The experimental methods and detection methods described in each example are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0087] Example 1

[0088] This example provides the synthesis of compound 6 (X is O, R1 and R2 are both H, L1 and L2 are both phenyl, Ar1 and Ar2 are both N-containing heteroaryl (carbazolyl)). The synthesis route is shown below and specifically includes the following steps:

[0089] ;

[0090] S1: Under nitrogen, a reaction flask was charged with starting material A (50.10 g, 136.9 mmol), starting material 1 (26.89 g, 137.0 mmol), ammonium acetate (26.37 g, 342.5 mmol), and glacial acetic acid (200 mL). The mixture was heated to reflux (110°C) for 5 h. After cooling to room temperature, the reaction solution was poured into cold water to produce a yellow precipitate. The filter cake was filtered and washed with water until neutral, then with ethanol, and dried to afford intermediate 6 (55.65 g, 75% yield).

[0091] S2: Under nitrogen, a reaction flask was charged with intermediate 6 (30.00 g, 55.4 mmol), starting material 2 (20.32 g, 121.8 mmol), sodium tert-butoxide (13.31 g, 138.5 mmol), and DMF (500 mL). Pd2(dba)3 (0.51 g, 0.55 mmol) and X-Phos (0.52 g, 1.11 mmol) were then added and heated to 106°C for 4 h. After the reaction, the mixture was cooled to room temperature and poured into water to produce a white precipitate, which was filtered. The precipitate was washed sequentially with water and ethanol. Finally, the mixture was passed through a silica gel column and recrystallized to obtain compound 6 (27.77 g, 70% yield).

[0092] The characterization results of compound 6 are as follows: HRMS: measured value: 717.2636 [M+H] + ; Exact mass: 717.2649. C 51 H 32 ON4 (%) calculated value: C, 85.45%; H, 4.50%; N, 7.82%; measured value: C, 85.38%; H, 4.50%; N, 7.82%.

[0093] Example 2

[0094] This example provides the synthesis of compound 10 (X is CR3R4, R3 and R4 are both methyl, R1 and R2 are both H, L1 and L2 are both phenyl, Ar1 and Ar2 are both N-containing heteroaryl (carbazolyl)). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 6, except that: in S1, raw material 1 is replaced by raw material 3, and compound 10 (28.36 g, yield 77%) is synthesized.

[0095] ;

[0096] The characterization results of compound 10 are as follows: HRMS: measured value: 743.3158 [M+H] + ; Exact mass: 743.3169. C 54 H 38 Calculated value of N4 (%): C, 87.30%; H, 5.16%; N, 7.54%; Found: C, 87.21%; H, 5.08%; N, 7.48%.

[0097] Example 3

[0098] This example provides the synthesis of compound 24 (X is NR5, R5 is phenyl, R1 and R2 are both H, L1 and L2 are both phenyl, Ar1 and Ar2 are both N-containing heteroaryl groups (triazine groups substituted with phenyl groups at the 3 and 5 positions)). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 6, except that in S1, raw material 1 is replaced by raw material 4, and intermediate 24 (59.39 g, yield 72%) is synthesized.

[0099] S2: Under nitrogen, a reaction flask was charged with intermediate 24 (35.00 g, 56.5 mmol), starting material 5 (60.90 g, 169.5 mmol), potassium carbonate (23.40 g, 170.0 mmol), water (100 mL), and THF (500 mL). Pd-132 (0.20 g, 0.55 mmol) was then added and heated to 60°C for 6 h. After the reaction, the mixture was cooled to room temperature and poured into water to form a white precipitate, which was filtered. The precipitate was washed sequentially with water and ethanol. Finally, the mixture was passed through a silica gel column and recrystallized to obtain compound 24 (40.36 g, 78% yield).

[0100] ;

[0101] The characterization results of compound 24 are as follows: HRMS: measured value: 924.3548 [M+H] + ; Exact mass: 924.3558. C 63 H 41Calculated value of N9 (%): C, 81.89%; H, 4.47%; N, 13.64%; Found: C, 81.76%; H, 4.38%; N, 13.54%.

[0102] Example 4

[0103] This example provides the synthesis of compound 51 (X is S, R1 and R2 are both H, L1 and L2 are both phenyl groups, Ar1 and Ar2 are both N-containing heteroaryl groups (carbazolyl groups substituted with phenyl groups)). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 24, except that raw material 4 is replaced by raw material 6 in S1, and raw material 5 is replaced by raw material 7 in S2, thereby obtaining compound 51 (59.39 g, yield 72%).

[0104] ;

[0105] The characterization results of compound 51 are as follows: HRMS: measured value: 885.3034 [M+H] + ; Exact mass: 885.3046. C 63 H 40 Calculated N4S (%): C, 85.49%; H, 4.56%; N, 6.33%; Found: C, 85.40%; H, 4.57%; N, 6.25%.

[0106] Example 5

[0107] This example provides the synthesis of compound 106 (X is O, R1 and R2 are both deuterated heteroaryl (carbazole-D8 group), L1 and L2 are both phenyl groups, and Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 6, except that: in S1, raw material A is replaced by raw material B, and raw material 1 is replaced by raw material 8; in S2, raw material 2 is replaced by raw material 9, and compound 106 (25.36 g, yield 70%) is synthesized.

[0108] ;

[0109] The characterization results of compound 106 are as follows: HRMS: measured value: 733.3647 [M+H] + ; Exact mass: 733.3653. C 51 H 16 D 16 Calculated value of N4O (%): C, 83.58%; H, 6.60%; N, 7.64%; measured value: C, 83.50%; H, 6.51%; N, 7.55%.

[0110] Example 6

[0111] This example provides the synthesis of compound 110 (X is CR3R4, R3 and R4 are both methyl, R1 and R2 are both deuterated heteroaryl (carbazole-D8 group), L1 and L2 are both phenyl, Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 106, except that in S1, raw material 8 is replaced by raw material 10, and compound 110 (26.23 g, yield 74%) is synthesized.

[0112] ;

[0113] The characterization results of compound 110 are as follows: HRMS: measured value: 759.4162 [M+H] + ; Exact mass: 759.4174. C 54 H 22 D 16 Calculated value of N4 (%): C, 85.45%; H, 7.17%; N, 7.38%; Found: C, 85.38%; H, 7.10%; N, 7.26%.

[0114] Example 7

[0115] This example provides the synthesis of compound 144 (X is NR5, R5 is a phenyl group with 6 hydrogen atoms deuterated, R1 and R2 are both heteroaryl groups (triazine groups substituted with phenyl groups at the 3 and 5 positions), L1 and L2 are both phenyl groups, and Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 24, except that in S1, raw material A is replaced by raw material B, and raw material 4 is replaced by raw material 11, to obtain compound 144 (59.39 g, yield 72%).

[0116] ;

[0117] The characterization results of compound 144 are as follows: HRMS: measured value: 929.3864 [M+H] + ; Exact mass: 929.3872. C 63 H 36 D5N9 (%) calculated value: C, 81.44%; H, 4.99%; N, 13.57%; found value: C, 81.38%; H, 4.79%; N, 13.46%.

[0118] Example 8

[0119] This example provides the synthesis of compound 171 (X is NR5, R5 is a C18 heteroaryl group, R1 and R2 are both hydrogen, L1 and L2 are both phenyl groups, and Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 110, except that in S1, raw material 10 is replaced by raw material 12, and compound 171 (21.52 g, yield 79%) is synthesized.

[0120] ;

[0121] The characterization results of compound 171 are as follows: HRMS: measured value: 635.3036 [M+H] + ; Exact mass: 635.3045. C 45 H 22 D8N4 (%) calculated value: C, 85.14%; H, 6.03%; N, 8.83%; found value: C, 85.05%; H, 5.92%; N, 8.71%.

[0122] Example 9

[0123] This example provides the synthesis of compound 186 (X is NR5, R5 is a C18 heteroaryl group, R1 and R2 are both hydrogen, L1 and L2 are both heteroaryl groups (pyridine), and Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 6, except that in S1, raw material A is replaced by raw material C, raw material 1 is replaced by raw material 12, and in S2, raw material 2 is replaced by raw material 9. Compound 186 (25.36 g, yield 70%) was synthesized.

[0124] ;

[0125] The characterization results of compound 186 are as follows: HRMS: measured value: 637.2576 [M+H] + ; Exact mass: 637.2590. C 43 H 20 D8N6 (%) calculated value: C, 81.11%; H, 5.70%; N, 13.20%; found value: C, 81.02%; H, 5.58%; N, 13.09%.

[0126] Example 10

[0127] This example provides the synthesis of compound 191 (X is CR3R4, R3 and R4 are both methyl, R1 and R2 are both deuterated heteroaryl (carbazole-D8 group), L1 and L2 are both heteroaryl (pyridine), and Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 186, except that in S1, raw material 12 is replaced by raw material 10, and compound 191 (29.35 g, yield 74%) is synthesized.

[0128] ;

[0129] The characterization results of compound 191 are as follows: HRMS: measured value: 743.3158 [M+H] + ; Exact mass: 743.3169. C 52 H 20 D 16 Calculated value of N6 (%): C, 82.11%; H, 4.29%; N, 8.42%; Found: C, 82.02%; H, 4.20%; N, 8.38%.

[0130] Example 11

[0131] This example provides the synthesis of compound 194 (X is NR5, R5 is a phenyl group with 6 hydrogen atoms deuterated, R1 and R2 are both heteroaryl groups (carbazolyl), L1 and L2 are both heteroaryl groups (pyridine), and Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 186, except that in S1, raw material 12 is replaced by raw material 11, and in S2, raw material 9 is replaced by raw material 2, to obtain compound 194 (27.58 g, yield 70%).

[0132] ;

[0133] The characterization results of compound 194 are as follows: HRMS: measured value: 799.3334 [M+H] + ; Exact mass: 799.3341. C 55 H 30 D5N7 (%) calculated value: C, 82.68%; H, 4.95%; N, 12.27%; found value: C, 82.52%; H, 4.83%; N, 12.05%.

[0134] Example 12

[0135] This example provides the synthesis of compound 208 (X is NR5, R5 is a heteroaryl group (a triazine group substituted with a phenyl group at the 3 and 5 positions), R1 and R2 are both hydrogen, L1 and L2 are both heteroaryl groups (pyridine), and Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 186, except that in S1, raw material 12 is replaced by raw material 13, and intermediate 208 (56.31 g, yield 72%) is synthesized.

[0136] S2: Under nitrogen, intermediate 208 (35.00 g, 90.3 mmol), starting material 14 (31.47 g, 117.6 mmol), potassium carbonate (18.72 g, 135.6 mmol), and DMF (300 mL) were added to a reaction flask. The mixture was heated to 150°C for 8 h. After the reaction, the mixture was cooled to room temperature and poured into water to form a white precipitate, which was filtered. The precipitate was washed with water and then ethanol. Finally, the mixture was passed through a silica gel column and recrystallized to obtain compound 208 (39.10 g, 70% yield).

[0137] ;

[0138] The characterization results of compound 208 are as follows: HRMS: measured value: 618.7158 [M+H] + ; Calculated value: 618.8360. C 40 H 26 Calculated value of N8 (%): C, 77.65%; H, 4.24%; N, 18.11%; measured value: C, 77.56%; H, 4.16%; N, 18.03%.

[0139] Example 13

[0140] This example provides the synthesis of compound 236 (X is O, R1 is carbazole, R2 is phenyl, L1 and L2 are both phenyl, Ar1 and Ar2 are both hydrogen). The synthesis route is shown below. The synthesis method refers to the syntheses of compounds 144 and 171, except that: in S1, raw material 12 is replaced by raw material 15, and in S2, raw material 9 is replaced by raw material 2, to obtain intermediate 236-2 (50.25 g, yield 70%).

[0141] S3: Under nitrogen, a reaction flask was charged with intermediate 236-2 (33.05 g, 56.5 mmol), starting material 16 (7.50 g, 62.15 mmol), potassium carbonate (11.69 g, 84.72 mmol), water (10 mL), and THF (30 mL). Pd-132 (0.05 g, 0.55 mmol) was then added and heated to 60°C for 6 h. After the reaction, the mixture was cooled to room temperature and poured into water to form a white precipitate, which was filtered. The precipitate was washed sequentially with water and ethanol. Finally, the mixture was passed through a silica gel column and recrystallized to obtain compound 236 (43.56 g, 74% yield).

[0142] ;

[0143] The characterization results of compound 236 are as follows: HRMS: measured value: 628.2374 [M+H]+; accurate mass: 628.2383. 45 H 29 ON3(%) calculated value: C, 86.10%; H, 4.66%, N, 6.69%; found value: C, 86.02%; H, 4.58%, N, 6.60%.

[0144] Example 14

[0145] This example provides the synthesis of compound 254 (X is NR5, R5 is phenyl, R1 and R2 are both hydrogen, Ar1 is carbazole, Ar2 is phenyl, L1 and L2 are both phenyl). The synthesis route is shown below. The synthesis method refers to the synthesis of compound 236, except that in S1, raw material 15 is replaced by raw material 4 to obtain compound 254 (26.53 g, yield 69%).

[0146] ;

[0147] The characterization results of compound 254 are: HRMS: m / z: 702.8642[M+H] + ; C 51 H 34 Calculated value of N4 (%): C, 87.15%; H, 4.88%; N, 7.97%; Found: C, 87.21%; H, 4.63%; N, 7.89%.

[0148] Example 15

[0149] This example simulates and calculates the physicochemical properties of the compound.

[0150] The HOMO, LUMO, and triplet state energies of Compounds 4, 6, 9, 10, 19, 21, 24, 29, 34, 39, 43, 51, 54, 67, 74, 75, 79, 81, 101, 104, 106, 110, 115, 144, 154, 165, 171, 179, 186, 191, 194, 208, 236, and 254, as well as the existing red light-emitting layer host materials RH1 and RH2 (structural formulas shown below), were simulated. The HOMO and LUMO values ​​were obtained from simulations using the B3LYP hybrid functional with a basis set of 6-31g (d, P). The results are shown in Table 1.

[0151] .

[0152] Table 1 T1 energy level and HOMO, LUMO simulation calculation results of the compounds

[0153]

[0154] As shown in Table 1, the compound with spiroimidazole as the core prepared in the present invention has relatively suitable HOMO, LUMO, and T1 values, and is suitable for use as a red light host material. When applied to OLED devices, it can effectively improve the luminous efficiency and service life of the device.

[0155] Example 14

[0156] This embodiment provides an application of the compound as a red light host material in an organic electroluminescent device.

[0157] The structure of organic electroluminescent devices is as follows Figure 1 As shown, it includes a substrate 1, an anode layer 2, a hole injection layer 3, a first hole transport layer 4, a second hole transport layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9 and a cathode layer 10 stacked in sequence.

[0158] In the comparative example, the material of the anode layer 2 of the organic electroluminescent device is indium tin oxide (ITO) with a high work function; the material of the hole injection layer 3 is HAT-CN with a thickness of 5 nm; the material of the first hole transport layer 4 is HT1 doped with HAT-CN, the mass percentage of HT1 and HAT-CN is 95%:5%, and the thickness is 60 nm; the material of the second hole transport layer 5 is HT2 with a thickness of 15 nm; the light-emitting layer 6 uses the first main material RH1 doped with the second main material RH2 as a mixed main material, the mass percentage of RH1 and RH2 is 47.5%:47.5%, RD01 is used as the light-emitting material, the doping mass percentage is 5%, and the thickness of the light-emitting layer 6 is 30 nm; the material of the hole blocking layer 7 is HB with a thickness of 10 nm; the electron transport layer 8 is composed of ET-1 doped with Liq, the mass percentage of ET-1 and Liq is 50%:50%, and the thickness is 30 nm; the material of the electron injection layer 9 is Liq with a thickness of 2 nm; the material of the cathode layer is Al with a thickness of 100 nm.

[0159] The structural formulas of the materials used in the functional layers of the organic electroluminescent device of the comparative example are as follows:

[0160] .

[0161] The preparation of the organic electroluminescent device of the comparative example includes the following steps:

[0162] 1) Clean the ITO anode on a transparent glass or plastic substrate, ultrasonically clean it with deionized water, acetone, and ethanol for 20 minutes each, and then plasma treat it in an oxygen atmosphere for 5 minutes; 2) Vacuum evaporation is used to deposit a hole injection layer on the ITO anode layer; 3) Vacuum co-evaporation is used to deposit a first hole transport layer HT1:HAT-CN on the hole injection layer; 4) Vacuum evaporation is used to deposit a second hole transport layer HT1:HAT-CN on the first hole transport layer HT1:HAT-CN; 5) Vacuum co-evaporation is used to deposit a light-emitting layer on the second hole transport layer; 6) Vacuum evaporation is used to deposit a hole blocking layer on the light-emitting layer; 7) Vacuum co-evaporation is used to deposit an electron transport material layer ET-1:Liq on the hole blocking layer; 8) Vacuum evaporation is used to deposit an electron injection layer on the electron transport layer; 9) Vacuum evaporation is used to deposit cathode Al on the electron injection layer.

[0163] Devices 1 through 20 were implemented in the same manner as the comparative example, except that the first host material in the light-emitting layer was replaced with a spiroimidazole-based compound prepared according to the present invention, replacing RH1. Devices 21 through 32 were implemented in the same manner as the comparative example, except that the second host material in the light-emitting layer was replaced with a spiroimidazole-based compound prepared according to the present invention, replacing RH2. Devices 33 through 36 were implemented in the same manner as the comparative example, except that the first and second host materials in the light-emitting layer were replaced with spiroimidazole-based compounds prepared according to the present invention, replacing RH1 and RH2, respectively. The light-emitting layer compositions of Devices 1 through 36 are shown in Table 2.

[0164] Devices 1 to 37 and the comparative organic electroluminescent device were connected to the cathode and anode using a known driving circuit. The voltage-efficiency-current density relationship of the OLED device was tested using a Keithley 2400 power supply and a PR670 photometer using a standard method. The life of the red light device was tested using a constant current method under the conditions of applying 20 mA / cm 2 Under constant current density, the device has an initial brightness of 100%. The time required for the brightness to decay to 95% of the initial brightness is the device's LT95 lifespan. The test results are shown in Table 2, and the test data are relative values.

[0165] Table 2 Performance parameters of organic electroluminescent devices

[0166]

[0167] As shown in Table 2, the compounds prepared in the present invention, when used as red light-emitting host materials in OLED devices, exhibit superior performance compared to existing OLED devices, with luminous efficiency increased by 15.2-41.6% and device life extended by 15.3-56.2%. For example, in device 16, using partially deuterated compound 171 as the first red light-emitting host material, both luminous efficiency and device life were significantly improved compared to the control example, with luminous efficiency increased by 41.6% and device life increased by 53.8%. In device 28, using compound 79 as the second red light-emitting host material, the device luminous efficiency increased by 28.9% and device life increased by 55.3%, compared to the control example. Using partially deuterated compound 179 and partially deuterated compound 164 as the first and second red light-emitting host materials, respectively, increased luminous efficiency by 39.3% and device life by 56.2%, respectively, compared to the control example. It can be seen that the application of the compound with spiroimidazole as the core of the present invention as the main material of the red light-emitting layer in OLED light-emitting devices has greatly improved the luminous efficiency and life performance compared with the existing material devices. It has great application value in the application of OLED devices and has good industrialization prospects.

[0168] The embodiments described above are part of the embodiments of the present invention, rather than all of them. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but merely represents selected embodiments of the present invention. All other embodiments obtained without creative effort and through deduction and substitution by a person of ordinary skill in the art based on the concept of the present invention are within the scope of protection of the present invention.

Claims

1. A compound, characterized in that Having a structure as shown in formula (I), ； X in the formula (I) is one of CR3R4, NR5, O, S, and Se; R1 and R2 in the formula (I) are independently selected from one of hydrogen, deuterium, substituted or unsubstituted amino derivatives, C6-C30 aryl groups, and heteroaryl groups; When R1 and R2 are C6~C30 aryl groups, the C6~C30 aryl groups are phenyl, biphenyl, and naphthyl; L1 and L2 in the formula (I) are independently selected from a single bond, a phenyl group, and a heteroaryl group; Ar1 and Ar2 in the formula (I) are independently selected from one of hydrogen, diphenylamino, substituted or unsubstituted C6-C30 aryl, and heteroaryl; R3 and R4 in the CR3R4 are independently selected from one of methyl and phenyl; R5 in the NR5 is one of a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted heteroaryl group; The heteroaryl group contains at least one heteroatom, and the heteroatom in the heteroaryl group is selected from N, O, and S atoms; The heteroaryl groups include carbazolyl, furyl, acridinyl, thienyl, triazinyl, pyrimidinyl, pyrazinyl, phenazinyl, pyridyl, benzimidazolyl, and phenanthroline; The substituted or unsubstituted amino derivative is selected from one of the following structures: ； The substituted or unsubstituted C6~C30 aryl group is selected from one of the following structures: ； The substituted or unsubstituted heteroaryl group is selected from one of the following structures: 。 2. The compound according to claim 1, characterized in that Has the structure shown below, 。 3. Use of the compound according to any one of claims 1 to 2 in an organic electroluminescent device, characterized in that: The compound is used as a red light host material in a light-emitting layer of an organic electroluminescent device.

4. An organic electroluminescent device comprising a light-emitting layer, characterized in that: The host material of the light-emitting layer includes the compound according to any one of claims 1 to 2.

5. A display component, characterized in that: The organic electroluminescent device according to claim 4 is included.

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