Host compound for organic electroluminescent devices

Abstract

The application belongs to the technical field of organic light-emitting materials, and relates to a host compound for an organic electroluminescent device. The compound provided by the application takes a benzazolinoimidazole or oxazole as a mother nucleus structure, connects an amine derivative group with electron-donating properties as a first light-emitting host, and connects a nitrogen-containing group with electron-withdrawing properties as a second light-emitting host, so that the compound constructed has a suitable triplet energy value and a frontier orbital energy level. When the compound provided by the application is used as a light-emitting host material, energy transfer between the host and the guest can be ensured. It is found through further verification that, when some specific groups are deuterated, the vibration of carbon-hydrogen bonds can be reduced, so that the stability of the material is significantly improved, and when the deuterated compound is used in an organic electroluminescent device, the luminous efficiency and the service life of the device are effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic light-emitting materials, and relates to a host compound for an organic electroluminescent device. BACKGROUND

[0002] An organic electroluminescent device (OLED) has been widely used in the fields of display and lighting due to its high efficiency, low power consumption, high contrast, lightness, portability and flexibility. Under the drive of an external electric field, the physical process in the OLED includes: holes are injected from an anode to an organic light-emitting layer, and electrons are injected from a cathode to the organic light-emitting layer. When the injected holes and electrons meet in the organic light-emitting layer, the holes and the electrons combine to form an exciton. When the exciton recombines from an excited state to a ground state, energy is released, and the released energy is emitted outward in the form of light, thereby realizing the light-emitting effect of the OLED.

[0003] At present, the organic electroluminescent device has been applied to a certain extent in the industrial field. However, the device generally has the problems of low efficiency and short service life, and the low service life is particularly fatal, which seriously hinders the further application and promotion thereof. In order to prepare an OLED device with excellent performance, firstly, a hole / electron transport material with excellent mobility needs to be screened out, so as to ensure that the electrons and holes in the light-emitting layer can achieve carrier balance, thereby guaranteeing the high-efficiency light-emitting of the OLED device; secondly, the light-emitting material is doped in a suitable host material, which can effectively reduce the exciton quenching effect, and thereby improve the photoelectric performance such as efficiency, brightness and service life of the OLED device. The light-emitting material is doped in a suitable host material. Therefore, a high-performance host material is crucial for realizing the performance of a high-quality OLED device.

[0004] For a phosphorescent OLED device, the selection of the host material is more stringent. The host material not only needs to have excellent carrier transport performance to ensure that the holes and the electrons can be efficiently injected into the light-emitting layer, but also needs to have a high triplet energy, so as to avoid the occurrence of exciton energy back transfer phenomenon. However, how to develop a high-quality host material which not only meets the above stringent requirements but also has good stability has always been a difficult and hot issue to be solved in the field of OLED technology. Although some host materials have been successfully developed and applied to OLED devices at present, these materials still have certain limitations in performance, and it is difficult to meet the increasing demand of the market for higher-quality OLED devices. Therefore, developing a high-performance host material is of great significance for promoting the development of OLED technology to a higher quality. SUMMARY

[0005] In order to solve the above problems and defects, the application provides a host compound for an organic electroluminescent device. The application is a compound obtained by modifying a benzazepine oxazole or oxazole as a mother nucleus with different groups. The compound has suitable front-line orbital energy level and triplet energy, and can be used as a red host material in an organic electroluminescent device, thereby improving the luminous efficiency and service life of the device.

[0006] In a first aspect, the application provides a compound, comprising at least one of a first host compound and a second host compound; the first host compound has a structure as shown in formula 1, and the second host compound has a structure as shown in formula 2,

[0007] , ;

[0008] wherein X and Y in the formula 1 or the formula 2 are selected from one of N(Ar3) and O, but at least one of X and Y is N(Ar3);

[0009] n in the formula 1 or m in the formula 2 is independently selected from an integer of 1 and 2;

[0010] L1 in the formula 1 is a bridging group, and L2 in the formula 2 is a single bond or a bridging group;

[0011] L1 and L2 are selected from one of a phenyl group, a biphenyl group and a naphthyl group;

[0012] Z1, Z2, Z3, Z4 and Z5 in the formula 2 are independently selected from one of C and N, and at most three of Z1, Z2, Z3, Z4 and Z5 are N;

[0013] When there are two adjacent C in Z1, Z2, Z3, Z4 and Z5 in the formula 2, the two adjacent C are bonded to form a ring with adjacent R6;

[0014] R6 in the formula 2 is selected from one of a substituted or unsubstituted C1-C10 alkane, a substituted or unsubstituted C1-C10 alkene, a C6-C30 aryl group, a heteroaryl group containing N or O heteroatoms and having a carbon number of C3-C30, and a substituent is an alkane, an alkene or an aryl group;

[0015] Ar1 and Ar2 in the formula 1 and Ar3 in N(Ar3) are independently selected from one of a C6-C30 aryl group and a heteroaryl group containing N or O heteroatoms and having a carbon number of C3-C30;

[0016] Ar1 and Ar2 in the formula 1 are the same or different; when m=2 in the formula 2, R6 is the same or different;

[0017] R1, R2, R3, R4, R5 in the formula 1 or R1, R2, R3, R4, R5 in the formula 2 are hydrogen or deuterium;

[0018] Ar1, Ar2 in the formula 1 are selected from one or more of phenyl, naphthyl, biphenyl, dibenzofuranyl, 9,9-dimethylfluorenyl, N-phenylcarbazolyl, respectively;

[0019] Ar1, Ar2 in the formula 1 are connected by single bond to form a carbazole ring or a carbazole fused ring;

[0020] Ar1, Ar2 in the formula 1, Ar3 in the N(Ar3), and hydrogen atom on R6 in the formula 2 can be deuterated.

[0021] Preferably, in the compound provided by the present application, Ar3 in the N(Ar3) is selected from one or more of phenyl, naphthyl, biphenyl.

[0022] Preferably, in the compound provided by the present application, R6 in the formula 2 is selected from one or more of phenyl, naphthyl, biphenyl, pyridine, pyrazine, pyridazine, pyrimidine.

[0023] Further, in the compound provided by the present application, the first host compound has a structure as shown in the formula 3~formula 6,

[0024]

[0025] .

[0026] Further, in the compound provided by the present application, the second host compound has a structure as shown in the formula 7~formula 10,

[0027]

[0028] .

[0029] Further, in the compound provided by the present application, the first host compound has a structure as shown below,

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] .

[0055] Further, the compound provided by the present application, the structure of the second host compound is shown as follows,

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] .

[0077] In a second aspect, the present application provides application of the above-mentioned compound in an organic electroluminescence device.

[0078] In a third aspect, the present application provides an organic electroluminescence device, comprising an anode layer, a cathode layer and an organic thin film layer between the anode layer and the cathode layer, wherein the organic thin film layer comprises a hole injection layer, a first hole transport layer, a second hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer, and the light-emitting layer contains the above-mentioned compound.

[0079] Compared with the prior art, the technical scheme provided by the present application has at least the following beneficial effects or advantages:

[0080] The present application takes benzacridine and imidazole or oxazole as a mother nucleus, connects an amine derivative group with electron-donating properties as a first light-emitting host, and connects a nitrogen-containing group with electron-withdrawing properties as a second light-emitting host, so that the newly constructed compound has a suitable triplet energy value and a front orbital energy level. When the compound provided by the present application is used as a light-emitting host material, energy transfer between the host and the guest can be ensured. Through further research, it is found that deuterium substitution of part of the groups in the compound significantly reduces the vibration of carbon-hydrogen bonds and significantly improves the stability of the material. The deuterated compound is used as a light-emitting layer host material in an organic electroluminescent device, which effectively improves the luminous efficiency and lifetime of the device. BRIEF DESCRIPTION OF DRAWINGS

[0081] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0082] Figure 1 The structure of the organic electroluminescent element is shown in the figure. In the figure, 1 is a substrate, 2 is an anode layer, 3 is a hole injection layer, 4 is a first hole transport layer, 5 is a second hole transport layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, and 10 is a cathode layer. DETAILED DESCRIPTION

[0083] The technical solutions of the present application will be described below in combination with the embodiments, but the present application is not limited to the following embodiments. The experimental methods and detection methods described in each embodiment are conventional methods unless otherwise specified. The reagents and materials described are commercially available unless otherwise specified. The % in the following examples is the mass percentage unless otherwise specified.

[0084] Preparation Example

[0085] The present preparation example provides a synthesis method of some intermediates and compounds, and the synthesis methods of the remaining intermediates and compounds are similar methods and can be easily synthesized. The specific synthesis routes are shown below.

[0086] Synthesis of intermediate 1:

[0087]

[0088] Synthesis of intermediate 1-1: under nitrogen protection, into a three-neck flask, add raw material 1 (348 g, 1 mol), raw material 2 (217 g, 1 mol), Pd(PPh3)4 (tetra (triphenylphosphine) palladium, 23 g, 0.02 mol), K2CO3 (potassium carbonate, 276 g, 2 mol), TBAB (tetrabutylammonium bromide, 32 g, 0.1 mol), toluene (2000 mL), ethanol (1000 mL), water (500 mL), heated to 76℃, stirred for 8h, then cooled to room temperature, washed with water to neutral, the organic phase was dried with anhydrous magnesium sulfate, then passed through a silica gel column, and then recrystallized with toluene / ethanol mixed solvent to purify to obtain 330 g of intermediate 1-1 with a yield of 70%.

[0089] Synthesis of intermediate 1: under nitrogen protection, into a three-neck flask, add intermediate 1-1 (220 g, 0.5 mol), PPh3 (triphenylphosphine, 262 g, 1 mol), o-dichlorobenzene (1000 mL), stirred and heated to 160℃ for 18h. After the reaction solution was cooled to room temperature, n-heptane was added to precipitate the solid product, which was filtered and recrystallized with toluene to purify to obtain 135 g of intermediate 1 with a yield of 66%.

[0090] Synthesis of intermediate 2:

[0091]

[0092] Synthesis of intermediate 2-1: refer to the synthesis of intermediate 1-1, replace raw material 1 with raw material 3;

[0093] Synthesis of intermediate 2: refer to the synthesis of intermediate 1, replace intermediate 1-1 with intermediate 2-1.

[0094] Synthesis of intermediate 3:

[0095]

[0096] Synthesis of intermediate 3-1: under nitrogen protection, into a three-neck flask, add raw material 4 (273 g, 1 mol), raw material 2 (217 g, 1 mol), Pd(PPh3)4 (tetra (triphenylphosphine) palladium, 23 g, 0.02 mol), K2CO3 (potassium carbonate, 276 g, 2 mol), TBAB (tetrabutylammonium bromide, 32 g, 0.1 mol), toluene (2000 mL), ethanol (1000 mL), water (500 mL), heated to 76℃, stirred for 6h, then cooled to room temperature, washed with water to neutral, the organic phase was dried with anhydrous magnesium sulfate, then passed through a silica gel column, and then recrystallized with toluene / n-heptane mixed solvent to purify to obtain 304 g of intermediate 3-1 with a yield of 83%.

[0097] Synthesis of intermediate 3: under nitrogen protection, intermediate 3-1 (183 g, 0.5 mol), PPh3 (triphenylphosphine, 262 g, 1 mol), o-dichlorobenzene (1000 mL) were added into a three-neck flask, heated to 160 °C for 14 h with stirring. After the reaction solution was cooled to room temperature, the solid product was precipitated by adding n-heptane, and then purified by recrystallization from toluene / ethanol to obtain 112 g of intermediate 3 with a yield of 67%.

[0098] Synthesis of intermediate 4:

[0099]

[0100] Synthesis of intermediate 4-1 refers to the synthesis of intermediate 3-1, replacing raw material 4 with raw material 5.

[0101] Synthesis of intermediate 4 refers to the synthesis of intermediate 3, replacing intermediate 3-1 with intermediate 4-1.

[0102] Synthesis of intermediate 5:

[0103]

[0104]

[0105] Synthesis of intermediate A-1: under nitrogen protection, raw material A-1 (187 g, 1 mol), pyridine (158 g, 2 mol), tetrahydrofuran (800 mL) were added into a three-neck flask, stirred and dissolved, then raw material A-2 (140 g, 1 mol) was added in three batches under ice bath, continued to stir for 30 min, then raised to room temperature and continued to react for 3 h. Dichloromethane (200 mL) was added, washed with water repeatedly, the organic phase was separated, dried over anhydrous magnesium sulfate, filtered, the filtrate was concentrated, and recrystallized with n-heptane to obtain 224 g of white solid intermediate A-1 with a yield of 77%.

[0106] Synthesis of intermediate A: under nitrogen protection, intermediate A-1 (146 g, 0.5 mol), TsOH (p-methylbenzenesulfonic acid, 172 g, 1 mol), toluene (800 mL) were added into a three-neck flask, stirred and dissolved, then the system was heated to 108 °C for 3 h. After the reaction solution was cooled to room temperature, it was washed with water, the organic phase was dried over anhydrous magnesium sulfate, filtered, the filtrate was concentrated, and then purified by recrystallization from toluene / ethanol to obtain 87 g of intermediate A with a yield of 64%.

[0107] Synthesis of intermediate 5-1 refers to the synthesis method of intermediate 3-1, replacing raw material 4 with intermediate A.

[0108] Synthesis of intermediate 5 refers to the synthesis method of intermediate 3, replacing intermediate 3-1 with intermediate 5-1.

[0109] Synthesis of intermediate B:

[0110]

[0111] Synthesis of intermediate B-1 was performed according to the synthesis of intermediate A-1, replacing starting material A-1 with starting material B-1.

[0112] Synthesis of intermediate B was performed according to the synthesis of intermediate A, replacing intermediate A-1 with intermediate B-1.

[0113] Synthesis of intermediate C:

[0114]

[0115] Synthesis of intermediate C-1: Under argon protection, a three-neck flask was charged with starting material C-2 (98 g, 1 mol), Pd2(dba)3(three (dibenzylideneacetone) palladium, 9 g, 10 mmol), P(t-Bu)3(tri-tert-butyl phosphine, 4 g, 20 mmol), sodium tert-butoxide (192 g, 2 mol), toluene (800 mL), stirred and heated to 110 °C reflux, added starting material C-1 (279 g, 1 mol) in 4 times, continued to react for 2 h. After the reaction was completed, it was cooled to room temperature, washed with water to neutral, the organic phase was dried with anhydrous magnesium sulfate, filtered, the filtrate was concentrated and purified by recrystallization with toluene to obtain 217 g of intermediate C-1, HPLC = 97.8941%, yield 73%.

[0116] Synthesis of intermediate C-2: Under nitrogen protection, a three-neck flask was charged with intermediate C-1 (146 g, 0.5 mol), dry tetrahydrofuran (600 mL), the system was stirred, Pd / C (14.6 g) was added, hydrazine hydrate was slowly added, and the temperature was slowly raised to 50 °C for 10 h. After the reaction was completed, it was cooled to room temperature, saturated sodium bicarbonate solution was added to terminate the reaction, dichloroethane (500 mL) was added for extraction, the organic phase was dried and filtered through a silica gel column, the column liquid was concentrated and purified by recrystallization with n-heptane to obtain 91.7 g of intermediate C-2, yield 70%.

[0117] Synthesis of intermediate C: Under nitrogen protection, a three-neck flask was charged with intermediate C-2 (52 g, 0.2 mol), benzaldehyde (21 g, 0.2 mol), DMF (200 mL), stirred and dissolved at room temperature, Na2S2O5(38 g, 0.2 mol) was added in three times, continued to stir for 8 h. Dichloroethane (600 mL) was added, repeatedly washed with water, the organic phase was dried with anhydrous magnesium sulfate, filtered and concentrated, recrystallized with toluene to obtain 41 g of intermediate C, yield 60%.

[0118] Synthesis of intermediate D:

[0119]

[0120] The synthesis of intermediate D-1 refers to the synthesis of intermediate C-1, and the raw materials C-1 and C-2 are replaced by raw materials D-1 and D-2.

[0121] The synthesis of intermediate D-2 refers to the synthesis of intermediate C-2, and intermediate C-1 is replaced by intermediate D-1.

[0122] The synthesis of intermediate D refers to the synthesis of intermediate C, and intermediate C-2 is replaced by intermediate D-2.

[0123] Referring to the synthesis methods of intermediates 1 to 5, other intermediates can be synthesized, and the only difference is that according to different products, corresponding intermediates need to be replaced, and the mass of the intermediate is changed according to the different molar amounts, as shown below:

[0124]

[0125] Synthesis of compound 1-1:

[0126]

[0127] Under nitrogen protection, a three-necked flask was added with intermediate 1 (40.9 g, 0.1 mol), raw material 1-1 (32.3 g, 0.1 mol), Pd2(dba)3 (tris(dibenzylideneacetone)dipalladium, 0.9 g, 1 mmol), P(t-Bu)3 (tris-tert-butyl phosphine, 0.4 g, 2 mmol), sodium tert-butoxide (19.2 g, 0.2 mol), toluene (300 mL), stirred and heated to 110°C reflux reaction for 2h. After the reaction was completed, it was cooled to room temperature, washed with water to neutral, and the organic phase was dried with anhydrous magnesium sulfate, filtered, the filtrate was passed through a silica gel column, the column liquid was concentrated, recrystallized with toluene, dried, and then sublimed at 290°C under high vacuum to obtain 35.8 g of white crystal compound 1-1, HPLC = 99.9877%, yield 55%, LC-MS: m / z 652.2627 [M+].

[0128] Synthesis of compound 1-22:

[0129]

[0130]

[0131] The synthesis of intermediate a-1 and intermediate 13 both refers to the synthesis method of compound 1-1, and only the corresponding reactants are replaced.

[0132] The synthesis of compound 1-22 was performed according to the synthetic method of compound 1-1 by replacing intermediate 1 and starting material 1-1 with intermediate 7 and intermediate 13. After synthesis and purification, compound 1-22 was obtained as white crystal after sublimation at 310 °C under high vacuum, HPLC = 99.9791%, yield 51%, LC-MS: m / z 742.2570 [M+].

[0133] Synthesis of compound 1-66:

[0134]

[0135] The synthesis of compound 1-66 was performed according to the synthetic method of compound 1-1 by replacing intermediate 1 and starting material 1-1 with intermediate 5 and starting material 1-3. After synthesis and purification, compound 1-66 was obtained as light yellow crystal after sublimation at 300 °C under high vacuum, HPLC = 99.9925%, yield 59%, LC-MS: m / z 653.2256 [M+].

[0136] Synthesis of compound 2-7:

[0137]

[0138] The synthesis of intermediate 14 was performed according to the synthesis of intermediate 3-1 by replacing the corresponding reactant starting material.

[0139] Synthesis of compound 2-7: Into a three-neck flask was placed intermediate 1 (40.9 g, 0.1 mol), intermediate 14 (46.3 g, 0.1 mol), Pd2(dba)3 (tris(dibenzylideneacetone)dipalladium, 0.9 g, 1 mmol), P(t-Bu)3 (tri-tert-butylphosphine, 0.4 g, 2 mmol), sodium tert-butoxide (19.2 g, 0.2 mol), toluene (400 mL) under nitrogen protection. The reaction mixture was stirred and heated to 110 °C for 3 h. After the reaction was completed, the reaction mixture was cooled to room temperature, washed with water until neutral, dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated and recrystallized with THF solvent. After purification and drying, compound 2-7 was obtained as white melt solid after sublimation at 320 °C under high vacuum, HPLC = 99.9912%, yield 47%, LC-MS: m / z 792.3001 [M+].

[0140] Synthesis of compound 2-35:

[0141]

[0142] The compound 2-35 was synthesized according to the synthetic method of the compound 2-7, by replacing the intermediate 1 and the intermediate 14 with the intermediate 2 and the raw material 1-5. After synthesis and purification, the white crystalline compound 2-35 was obtained by high vacuum sublimation at 315°C, HPLC = 99.9836%, yield 60%, LC-MS: m / z 613.2266 [M+].

[0143] Synthesis of the compound 2-66:

[0144]

[0145] Synthesis of the intermediate 15

[0146] The compound 2-66 was synthesized according to the synthetic method of the compound 2-7, by replacing the intermediate 1 and the intermediate 14 with the intermediate 6 and the intermediate 15. After synthesis and purification, the light yellow molten solid compound 2-66 was obtained by high vacuum sublimation at 320°C, HPLC = 99.9818%, yield 58%, LC-MS: m / z 690.2208 [M+].

[0147] According to the above synthetic method of the compound, all the compounds in the application can be synthesized, and the only difference is that different intermediates need to be used for replacement according to different products, and the mass of the intermediate is changed according to the different molar amount.

[0148] The performance parameters (including HOMO energy level, LUMO energy level and triplet energy T1) of some compounds synthesized in the application and the existing OLED materials RH1 and RH2 were measured, and the results are shown in Table 1.

[0149] Table 1: Performance parameter measurement results of compounds and existing materials

[0150]

[0151] Note: The highest molecular orbital (HOMO), the lowest molecular unoccupied orbital (LUMO) and the triplet energy T1 data are obtained by Gaussian 09 software simulation calculation, and the calculation method adopts B3LYP hybrid functional and the basis set 6-31g(d).

[0152] As can be seen from Table 1, the compound provided by the application has suitable triplet energy, HOMO energy level and LUMO energy level, which is beneficial to the transport of carriers and the energy transfer between the host and the guest in the OLED device. The compound of the application is suitable as a light-emitting host material in the OLED device.

[0153] The following takes some compounds provided by the present application as examples, which are applied to organic electroluminescent devices as light-emitting host materials to verify the excellent effects achieved thereby.

[0154] The excellent effects of the OLED materials of the present application applied in devices are illustrated in detail by the device performances of Examples 1-28 and Comparative Examples. The structures of Examples 1-28 and Comparative Examples of the present application are completely the same, and the same glass substrate and electrode material are used, and the film thickness of the electrode material is also kept consistent, the difference is that the light-emitting layer host material is adjusted, which is specifically as follows.

[0155] Comparative Example

[0156] The present comparative example provides an organic electroluminescent device, the structure of which is specifically as shown in Figure 1 The organic electroluminescent device comprises, in sequence, 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.

[0157] The substrate 1 is a glass substrate with a thickness of 0.7 mm, the material of the anode layer 2 is indium tin oxide (ITO) with a high work function, the material of the hole injection layer 3 is HAT-CN, and the thickness is 5 nm; the material of the first hole transport layer 4 is HT1, and the thickness is 60 nm; the material of the second hole transport layer 5 is HT2, and the thickness is 15 nm; the light-emitting layer 6 uses the first host material RH1 doped with the second host material RH2 as the mixed host material, the mass percentage of RH1 and RH2 is 47.5%:47.5%, RD01 is used as the light-emitting material, and the doping mass percentage is 5%, and the thickness of the light-emitting layer is 30 nm; the material of the hole blocking layer 7 is HB1, and the thickness is 10 nm; the material of the electron transport layer 8 is ET1, and the thickness is 30 nm; the material of the electron injection layer 9 is Liq, and the thickness is 2 nm; and the material of the cathode layer is Al, and the thickness is 100 nm.

[0158] The basic material structure used in each functional layer of the comparative example organic electroluminescent device is as follows:

[0159]

[0160]

[0161] The specific preparation steps of the comparative example organic electroluminescent device are as follows:

[0162] (1) Clean the ITO anode on the transparent glass or plastic substrate, respectively ultrasonic clean with deionized water, acetone, and ethanol for 20 min, and then perform plasma treatment in oxygen atmosphere for 5 min;

[0163] (2) On the ITO anode layer, a hole injection layer material HAT-CN is evaporated by vacuum evaporation method, with a thickness of 5 nm, which serves as a hole injection layer;

[0164] (3) On the hole injection layer, a first hole transport material HT1 is evaporated by vacuum evaporation method, with a thickness of 60 nm, which serves as a first hole transport layer;

[0165] (4) On the first hole transport layer HT1, a second hole transport material HT2 is evaporated by vacuum evaporation method, with a thickness of 15 nm, which serves as a second hole transport layer;

[0166] (5) On the second hole transport layer, a light-emitting layer is evaporated by a three-source co-evaporation method, using RH1 as a first host material and RH2 as a second host material, with a mass percentage of RH1 and RH2 being 47.5%:47.5% as a mixed host material, and the mixed host material and a light-emitting material RD01 are evaporated at the same time, with a doping mass ratio of RD01 being 5%, and the light-emitting layer has a thickness of 30 nm;

[0167] (6) On the light-emitting layer, a hole blocking material HB1 is evaporated by vacuum evaporation method, with a thickness of 10 nm, which serves as a hole blocking layer;

[0168] (7) On the hole blocking layer, an electron transport material ET1 is evaporated by vacuum evaporation method, with a thickness of 30 nm, which serves as an electron transport layer;

[0169] (8) On the electron transport layer, an electron injection material Liq is evaporated by vacuum evaporation method, with a thickness of 2 nm, which serves as an electron injection layer;

[0170] (9) On the electron injection layer, a cathode Al is evaporated by vacuum evaporation method, with a thickness of 100 nm, which serves as a cathode conductive electrode, and this layer is the cathode layer.

[0171] Examples 1 to 28 were prepared in the same manner as Comparative Example 1, except that Compound 1-1, Compound 1-14, Compound 1-22, Compound 1-27, Compound 1-37, Compound 1-48, Compound 1-53, Compound 1-66, Compound 1-82, Compound 1-87 and Compound 1-94 were used instead of the first host material RH1; Compound 2-1, Compound 2-7, Compound 2-9, Compound 2-21, Compound 2-27, Compound 2-35, Compound 2-53, Compound 2-66, Compound 2-69, Compound 2-75 and Compound 2-84 were used instead of the second host material RH2; Compound 1-1 and Compound 2-7 were used instead of the first host material RH1 and the second host material RH2, respectively; and the same was true for Compound 1-14 and Compound 2-21, Compound 1-37 and Compound 2-84, Compound 1-22 and Compound 2-7, Compound 1-48 and Compound 2-21, Compound 1-82 and Compound 2-66.

[0172] The organic electroluminescent devices of Examples 1 to 28 and Comparative Example were connected to a cathode and an anode by a known driving circuit, and the voltage-efficiency-current density relationship of the OLED device was tested by a standard method using a Keithley 2400 power supply in combination with a PR670 photometer; the lifetime of the red light device was tested by a constant current method, and the test conditions were that the device was applied with a constant current density of 20 mA / cm2, and the time required for the luminance to decay to 95% of the initial luminance was the LT95 lifetime of the device. 2 The initial luminance of the device was 100% at a constant current density, and the time required for the luminance to decay to 95% of the initial luminance was the LT95 lifetime of the device; the light-emitting layer composition of Examples 1 to 28 and the test results are shown in Table 2, and the test data are relative values (%).

[0173] Table 2: Performance test results of the organic electroluminescent devices of the examples

[0174]

[0175] As can be seen from Table 2, the compound prepared in the application is applied to the OLED device as a red light host material, and the performance is better than that of the existing OLED device, the luminous efficiency is increased by 15-56%, and the device life is prolonged by 19-60%. In Example 5, the partially deuterated compound 1-37 is used as a red light first host material, and compared with the comparative example, the luminous efficiency and service life are significantly improved, the luminous efficiency is increased by 41%, and the device life is increased by 53%; in Example 19, the partially deuterated compound 2-66 is used as a red light second host material, and compared with the comparative example, the device luminous efficiency is increased by 44%, and the device life is increased by 47%; in Example 25, the partially deuterated compound 1-37 and the partially deuterated compound 2-84 are used as a red light first host material and a red light second host material respectively, and compared with the comparative example, the luminous efficiency is increased by 56%, and the device life is increased by 60%. The compound of the application is applied to the OLED light-emitting device as a red light emitting layer host material, and compared with the luminous efficiency and life performance of the existing material device, the luminous efficiency and life performance are greatly improved, and the application in the OLED device has great application value, and has good industrialization prospect.

[0176] As described above, the basic principles, main features and advantages of the application are better described. The above examples and specification only describe the preferred embodiments of the application, and the application is not limited by the above examples. Without departing from the spirit and scope of the application, various changes and improvements to the technical solutions of the application made by those skilled in the art shall fall within the scope of protection of the application.

Claims

1. A compound, characterized in that Containing at least one of a first host compound and a second host compound; The first host compound has a structure as shown in Formula 1, and the second host compound has a structure as shown in Formula 2. ， ； Wherein, X and Y are each selected from one of N(Ar3) and O, but at least one of X and Y is N(Ar3); Said n or m is independently selected from 1 and 2 integers; The L1 is a bridging group, and the L2 is a single bond or a bridging group; The L1 bridging group and the L2 bridging group are selected from one of phenyl, biphenyl and naphthyl; Said Z1, Z2, Z3, Z4, and Z5 are independently selected from one of C and N, and at most three of Z1, Z2, Z3, Z4, and Z5 are N; R6 is selected from one of a C6-C30 aryl group and a C3-C30 heteroaryl group containing a N or O heteroatom; Said Ar3 is phenyl; Ar1 and Ar2 are the same or different; when m=2, R6 are the same or different; R1, R2, R3, R4, and R5 are hydrogen or deuterium; Ar1 and Ar2 are selected from one or more of phenyl, naphthyl, biphenyl, dibenzofuranyl, 9,9-dimethylfluorenyl and N-phenylcarbazolyl; The hydrogen atoms on Ar1, Ar2, Ar3 and R6 can all be deuterated.

2. The compound according to claim 1, characterized in that The first host compound has a structure as shown in Formula 3 to Formula 6, 。 3. The compound according to claim 1, characterized in that The second host compound has a structure as shown in Formula 7 to Formula 10, 。 4. The compound according to claim 1, characterized in that The structure of the first host compound is shown below: 。 5. The compound according to claim 1, characterized in that The structure of the second host compound is shown below: 。 6. Use of the compound according to any one of claims 1 to 5 in an organic electroluminescent device.

7. An organic electroluminescent device comprising an anode layer, a cathode layer, and an organic thin film layer located between the anode layer and the cathode layer, wherein the organic thin film layer comprises a hole injection layer, a first hole transport layer, a second hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, characterized in that: The light-emitting layer contains the compound according to any one of claims 1 to 5.

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