Organic electroluminescent compound and organic electroluminescent device

Abstract

The present invention discloses an organic electroluminescent compound and an organic electroluminescent device, and the structural formula thereof is shown in the following formula 1. The present invention designs an organic electroluminescent compound and an organic electroluminescent device containing the compound, wherein a deuterated carbazole group is introduced into the molecular formula of the compound, so as to improve the thermal stability and chemical stability of the carbazole group, reduce the luminous voltage of the device, increase the service life, and greatly increase the service life of the device, and can effectively improve the thermal stability and chemical stability of the compound molecule, thereby increasing the service life and efficiency of the device prepared using the compound; the compound is applied to an organic electroluminescent device and used as an electron blocking layer, so that the luminous efficiency of the organic electroluminescent device can be greatly improved, and the starting voltage is reduced, the power consumption is relatively reduced, and the service life is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of organic electroluminescence, and in particular to an organic electroluminescent compound and an organic electroluminescent device. Background Art

[0002] Research on improving the performance of organic electroluminescent devices includes: reducing the driving voltage of the device, improving the luminous efficiency of the device, and increasing the service life of the device. In order to continuously improve the performance of organic electroluminescent devices, it is necessary not only to innovate the structure and manufacturing process of organic electroluminescent devices, but also to continuously research and innovate organic electrophotoelectric functional materials to create higher performance organic electroluminescent functional materials.

[0003] In OLED, since the mobility of holes is faster than that of electrons, the charge in the light-emitting layer is unbalanced, which reduces the color purity, luminous efficiency and life of the organic electroluminescent device. The efficiency cannot be maximized by simply improving the organic materials of the light-emitting layer. Therefore, it is urgent to find a luminescent auxiliary material to improve the luminous efficiency and life of the organic electroluminescent device. At present, the materials used for the light-emitting auxiliary layer generally have a low triplet energy level T1 due to their aromatic amine structure, and cannot prevent the excitons after carrier recombination from expanding to the transport layer, resulting in reduced luminous efficiency. In addition, most of the existing auxiliary layer materials have a high evaporation temperature and cannot withstand long-term heating, which limits their practical applications.

[0004] As far as the actual needs of the current organic electroluminescent industry are concerned, the current development of organic electroluminescent materials is far from enough and lags far behind the requirements of panel manufacturers. In addition, the research pace of domestic companies is also far behind that of American, Japanese and Korean companies. Therefore, developing and providing more selectable organic electroluminescent materials is the top priority for domestic panel companies. Summary of the invention

[0005] Purpose of the invention: In view of the above technical problems, the present invention provides an organic electroluminescent compound and an organic electroluminescent device.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0007] An organic electroluminescent compound, the structural formula of which is shown in Formula 1 below:

[0008]

[0009] Its R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R8 At least one of them is deuterium, and the rest are hydrogen. 9 , R 10 is hydrogen or deuterium;

[0010] m, o are positive integers from 0 to 4;

[0011] n is 0 or 1;

[0012] Ar 1 ,Ar 2 is a substituted or unsubstituted C6-C30 aromatic group, a substituted or unsubstituted C5-C30 heteroaryl group, and Ar 1 ,Ar 2 At least one of them is a substituted or unsubstituted C5-C30 heteroaryl group;

[0013] The substituted C6-C30 aromatic group or C5-C30 heteroaromatic group is a group in which at least one hydrogen is replaced by deuterium, cyano, alkyl having 1-4 carbon atoms, deuterated alkyl having 1-4 carbon atoms, aryl having 6-20 carbon atoms, or heteroaryl having 3-20 carbon atoms.

[0014] Further, its structural formula is shown in Formula 2, Formula 3 or Formula 4 below:

[0015]

[0016] Here R 1 -R 10 ,m、o、n、Ar 1 ,Ar 2 The meaning is the same as in claim 1.

[0017] Furthermore, Ar 1 ,Ar 2 are each independently substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, and Ar 1 ,Ar 2 At least one of them is a substituted or unsubstituted dibenzofuranyl group, or a substituted or unsubstituted dibenzothiophenyl group;

[0018] The phenyl, biphenyl, terphenyl, naphthyl, dibenzofuranyl, and dibenzothiophenyl groups are unsubstituted or at least one hydrogen therein is substituted by deuterium, cyano, an alkyl group having 1 to 4 carbon atoms, a deuterated alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 3 to 20 carbon atoms.

[0019] Furthermore, Ar 1 ,Ar 2are each independently substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, and Ar 1 ,Ar 2 At least one of them is a substituted or unsubstituted dibenzofuranyl group, or a substituted or unsubstituted dibenzothiophenyl group;

[0020] The phenyl, biphenyl, terphenyl, naphthyl, dibenzofuranyl, and dibenzothiophene are unsubstituted or are groups in which at least one hydrogen is substituted by deuterium, cyano, phenyl, or biphenyl.

[0021] Furthermore, Ar 1 is a substituted or unsubstituted biphenyl group, Ar 2 is a substituted or unsubstituted dibenzofuranyl group, or a substituted or unsubstituted dibenzothiophene group;

[0022] The biphenyl group, dibenzofuranyl group and dibenzothiophene group are unsubstituted or are groups in which at least one hydrogen is substituted by deuterium, cyano, phenyl or biphenyl.

[0023] Furthermore, the organic electroluminescent compound is any one of the following compounds:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] The compound having the structure shown in Formula 1 of the present invention has the following synthesis reaction route:

[0040]

[0041] An organic electroluminescent device comprises a first electrode, a second electrode and an organic layer formed between the first electrode and the second electrode, wherein the organic layer contains the organic electroluminescent compound mentioned above.

[0042] Furthermore, the organic layer comprises a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; and at least one of the hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, and electron injection layer contains the above-mentioned organic electroluminescent compound.

[0043] Furthermore, the electron blocking layer contains the above-mentioned organic electroluminescent compound.

[0044] The room temperature described in the present invention is 25±5°C.

[0045] Beneficial effects of the present invention:

[0046] The present invention designs an organic electroluminescent compound and an organic electroluminescent device containing the compound. The present invention introduces deuterium to the carbazole group in the molecular formula of the compound, improves the thermal stability and chemical stability of the carbazole group, reduces the light-emitting voltage of the device, increases the service life and greatly increases the life of the device, can effectively improve the thermal stability and chemical stability of the compound molecule, and thus increases the life and efficiency of the device prepared using the compound. At the same time, considering the cost performance of the product, the special selection of the deuterium position on the carbazole and the different amounts will have a significant impact on the organic electroluminescent performance of the compound. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram of the structure of an organic electroluminescent device provided by the present invention;

[0048] The numbers in the figure represent:

[0049] 1- anode, 2- hole injection layer, 3- hole transport layer, 4- electron blocking layer, 5- light emitting layer, 6- hole blocking layer, 7- electron transport layer, 8- electron injection layer, 9- cathode.

[0050] Figure 2is the H NMR spectrum of the organic electroluminescent compound 9 prepared in Example 1 of the present invention;

[0051] Figure 3 This is the HPLC chart of compound 9 prepared in Example 1 of the present invention.

[0052] Figure 4 is the DSC spectrum of compound 9 prepared in Example 1 of the present invention, Figure 4 It can be seen that the Tg value of compound 9 is 131.24°C.

[0053] Figure 5 is the TGA spectrum of compound 9 prepared in Example 1 of the present invention, Figure 5 It can be seen that the thermal weight loss temperature Td value is 516.00℃.

[0054] Figure 6 is a life graph of the organic electroluminescent device in Application Example 1 and Comparative Example 1 of the present invention; Figure 6 It can be seen that the T97% lifespans of the organic electroluminescent devices prepared in Application Example 1 and Comparative Example 1 of the present invention are 459 h and 358 h, respectively. DETAILED DESCRIPTION

[0055] The following further illustrates and describes embodiments of various aspects. It should be understood that the description herein is not intended to limit the claims to the specific aspects described. On the contrary, it is intended to cover substitutions, modifications and equivalents that may be included in the spirit and scope of the present disclosure defined by the appended claims.

[0056] As used herein, a "Ca to Cb" hydrocarbon group is defined as a hydrocarbon group having a carbon number of "a" (inclusive) to "b" (inclusive). As used herein, "a and / or b" means "a" or "b" or "a and b".

[0057] As used herein, in "substituted" or "unsubstituted", the term "substituted" means that at least one hydrogen in the group is re-coordinated with deuterium, a hydrocarbon group, a hydrocarbon derivative group, a halogen, or a cyano group (-CN). The term "unsubstituted" means that at least one hydrogen in the group is not re-coordinated with deuterium, a hydrocarbon group, a hydrocarbon derivative group, a halogen, or a cyano group (-CN). Examples of hydrocarbon groups or hydrocarbon derivative groups may include C1 to C30 alkyl, C2 to C30 alkenyl, C2 to C30 alkynyl, C6 to C30 aryl, C5 to C30 heteroaryl, C1 to C30 alkylamino, C6 to C30 arylamino, C6 to C30 heteroarylamino, C6 to C30 arylheteroarylamino, etc., but are not limited thereto.

[0058] As used herein, “R 1 , R 2 , R 3 , R 4, R 5 , R 6 , R 7 , R 8 At least one of them is deuterium and the rest are hydrogen" means R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 One of the positions is deuterium, and the remaining seven positions on the carbazole are hydrogen; or R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 Two of them are deuterium, and the remaining six positions on the carbazole are hydrogen; or R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 Three of them are deuterium, and the remaining five positions on the carbazole are hydrogen; or R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 Four of them are deuterium, and the remaining four positions on the carbazole are hydrogen; or R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 Five of them are deuterium, and the remaining three positions on carbazole are hydrogen; or R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 Six of them are deuterium, and the remaining two positions on carbazole are hydrogen; or R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R7 , R 8 Seven of them are deuterium, and the remaining position on carbazole is hydrogen; or R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 All are deuterium;

[0059] As used herein, an alkyl group having 1 to 4 carbon atoms refers to a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group;

[0060] As used herein, a deuterated alkyl group having 1 to 4 carbon atoms refers to a group obtained by replacing at least one hydrogen in a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group with deuterium;

[0061] As used herein, in "deuterated" or "undeuterated", the term "deuterated" means that at least one hydrogen in the group is re-coordinated with deuterium. The term "undeuterated" means that all hydrogens in the group are not re-coordinated with deuterium.

[0062] "Cycloalkyl" herein refers to a monocyclic or fused ring ("fused" ring means that each ring in the system shares a pair of adjacent carbon atoms with other rings in the system) group that is all carbon, wherein one or more rings are saturated alicyclic rings, which generally have 3-20 carbon atoms, preferably 3-12 carbon atoms, and more preferably 3-10 carbon atoms. Cycloalkyl can be divided into monocyclic alkyls having only one ring and fused cyclic alkyls having multiple rings. Examples of monocyclic alkyls include, but are not limited to, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane. Cycloalkyl can be substituted and unsubstituted.

[0063] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0064] Embodiment 1:

[0065]

[0066] The synthesis method of compound 9 is as follows:

[0067]

[0068] S1: Under nitrogen protection, phenylboronic acid 1-b (29.1 g, 0.2383 mol, 1.1 eq), halide 1-a (61 g, 0.2166 mol, 1 eq), 500 ml of toluene, potassium carbonate (89.7 g, 0.65 mol, 3 eq), tetrakistriphenylphosphine palladium (2.5 g, 0.0021 mol, 1% eq), 320 ml of ethanol, and 320 ml of water were added to a 2 L reaction bottle. After the addition was completed, the reaction solution was heated to 85 ° C and refluxed overnight. The raw material reaction was detected by HPLC. Turn off the heating, cool to room temperature, add 500 ml of water and stir for half an hour, pour the reaction solution into a 3L separatory funnel and let it stand for 10 minutes, separate the liquid, pass the organic phase through silica gel, rinse the silica gel with 200 ml of toluene, spin dry the organic phase, add 200 ml of ethanol and cool to -10°C to precipitate a large amount of solid, filter, dry in an oven at 60°C, combine the organic phases to obtain solid compound 1-c (about 50 g, yield is about 83%), ESI-MS (m / z) (M+): theoretical value 278.74, measured value 278.80, elemental analysis results (molecular formula C18H11ClO): theoretical value C, 77.56; H, 3.98; Cl, ​​12.72; O, 5.74; measured value C, 77.55; H, 3.99; Cl, ​​12.71; O, 5.75.

[0069] S2: Under nitrogen protection, the intermediate 1-c (50 g, 0.1794 mol, 1 eq), amine 1-d (33.3 g, 0.1973 mol, 1.1 eq), 500 ml of toluene, sodium tert-butoxide (20.6 g, 0.2153 mol, 1.2 eq), palladium acetate (0.3 g, 0.0018 mol, 1% eq) and x-phos (1.7, 0.0036 mol, 2% eq) were added to the reaction flask. After the addition was completed, the reaction solution was heated to 110 ° C and refluxed for 4 hours. The raw material reaction was complete after sampling HPLC detection. The reaction solution Pass the silica gel while hot, rinse the silica gel with 300 ml of toluene, spin-dry the filtrate to form a solid, reflux with 300 ml of ethanol for 1 h, cool to room temperature, filter, and dry the filter cake in an oven at 85°C to obtain 1-e (about 62 g, yield about 84%), ESI-MS (m / z) (M+): theoretical value 411.50, measured value 411.45, elemental analysis results (molecular formula C30H21NO): theoretical value C, 87.56; H, 5.14; N, 3.40; O, 3.89; measured value C, 87.57; H, 5.15; N, 3.39; O, 3.89.

[0070] S3: Under nitrogen protection, deuterated carbazole 1-f (28.3 g, 0.1695 mol, 1 eq), halide 1-g (47.6 g, 0.1775 mol, 1.05 eq), 500 ml of xylene, sodium tert-butoxide (19.5 g, 0.2034 mol, 1.2 eq), Pd2(dba)3 (3 g, 0.0016 mol, 1% eq) and tri-tert-butylphosphine (3.6 ml, 0.0032 mol, 2% eq) were added to the reaction bottle. After the addition was completed, the reaction solution was heated to 140°C and refluxed overnight. The raw material reaction was detected by HPLC. The reaction solution was passed through silica gel while hot and filtered for 30 min. 0ml toluene was used to wash the silica gel, the filtrate was spin-dried, refluxed with 300ml ethanol for 1h to form a solid, cooled to room temperature, filtered, the filter cake was dried in an oven at 85°C, recrystallized once with 50ml toluene and 100ml ethanol, and solid 1-h (about 38.7g, yield about 60%) was obtained, ESI-MS (m / z) (M+): theoretical value 361.90, measured value 361.97, elemental analysis results (molecular formula C24H24D24ClN): theoretical value C, 79.65; H, 6.68; Cl, ​​9.80; N, 3.87; measured value 79.60; H, 6.71; Cl, ​​9.82; N, 3.87.

[0071] S4: Under nitrogen protection, the intermediate 1-e (40 g, 0.0972 mol, 1 eq), the intermediate 1-h (38.7 g, 0.1069 mol, 1.1 eq), 500 ml of toluene, sodium tert-butoxide (11.2 g, 0.1165 mol, 1.2 eq), palladium acetate (0.16 g, 0.0010 mol, 1% eq) and x-phos (0.9, 0.0020 mol, 2% eq) were added to the reaction flask. After the addition was completed, the reaction solution was heated to 110 ° C and refluxed overnight. The raw material reaction was detected by HPLC sampling to ensure that the reaction was complete. The reaction solution was passed through silica gel while hot, and the silica gel was rinsed with 300 ml of toluene. The filtrate was dried by rotary evaporation, refluxed with 150 ml of ethyl acetate for 1 hour to form a solid, cooled to room temperature, filtered, the filter cake was dried in an oven at 85°C, and recrystallized 6 times with 250 ml of toluene and 200 ml of ethanol. The purity was 99.99%, and compound 9 (about 42 g, yield about 60%) was obtained. ESI-MS (m / z) (M+): theoretical value 736.94, measured value 736.86, elemental analysis results (molecular formula C54H28D8N2O): theoretical value C, 88.01; H, 6.02; N, 3.80; O, 2.17; measured value C, 88.00; H, 6.05; N, 3.80; O, 2.15.

[0072] The following product compounds were obtained in a similar manner:

[0073] Table 1

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081] Embodiment 35:

[0082]

[0083] The preparation method of the organic electroluminescent compound 64 is as follows:

[0084]

[0085] The preparation method is basically the same as that of Example 1, except that step S0 is added: under nitrogen protection, a halide (32.5 g, 0.1 mol, 1 eq) is added to the reaction bottle, THF500 ml is dried, the temperature is lowered to -78 ° C, 1.6 M n-butyl lithium (197 ml, 0.31 mol, 3.1 eq) is added dropwise, after the addition is complete, the temperature is kept at -78 ° C and stirred for 1 h, heavy water (250 g, 12.5 mol, 125 eq) is added dropwise, and the temperature is naturally raised to room temperature and stirred for 12 h. After post-treatment, the reaction solution is added with water, separated, and the organic phase is concentrated to dryness to obtain about 13.6 g of the intermediate product 35-f, with a yield of about 80%. Compound 1-a was replaced by compound 35-a, and the final yield of compound 64 was 63.3%, ESI-MS (m / z) (M+): theoretical value 730.91, measured value 730.80, elemental analysis results (molecular formula C54H34D2N2O): theoretical value C, 88.74; H, 5.24; N, 3.83; O, 2.19; measured value C, 88.78; H, 5.18; N, 3.84; O, 2.20.

[0086] The following product compounds were obtained in a similar manner:

[0087] Table 2

[0088]

[0089]

[0090]

[0091] Embodiment 46:

[0092]

[0093] The preparation method of the organic electroluminescent compound 26 is as follows:

[0094]

[0095] The preparation method is basically the same as that of Example 1, except that step S0 is added: under nitrogen protection, a halide (40.4 g, 0.1 mol, 1 eq) is added to the reaction bottle, THF500 ml is dried, the temperature is lowered to -78 ° C, 1.6 M n-butyl lithium (256 ml, 0.41 mol, 4.1 eq) is added dropwise, after the addition is complete, the temperature is kept at -78 ° C and stirred for 1 h, heavy water (250 g, 12.5 mol, 125 eq) is added dropwise, and the temperature is naturally raised to room temperature and stirred for 12 h. After post-treatment, the reaction solution is added with water, separated, and the organic phase is concentrated to dryness to obtain about 13.68 g of the intermediate product 46-f, with a yield of about 80%. Compound 1-h was replaced by compound 46-h, and the final yield of compound 26 was 60.9%, ESI-MS (m / z) (M+): theoretical value 731.91, measured value 731.94, elemental analysis results (molecular formula C54H33D3N2O): theoretical value C, 88.62; H, 5.37; N, 3.83; O, 2.19; measured value C, 88.60; H, 5.38; N, 3.82; O, 2.20.

[0096] The following product compounds were obtained in a similar manner:

[0097] Table 3

[0098]

[0099]

[0100] Embodiment 54:

[0101]

[0102] The preparation method of the organic electroluminescent compound 128 is as follows:

[0103]

[0104]

[0105] The preparation method is basically the same as that of Example 1, except that steps S-2 to S0 are added:

[0106] S-2: Under nitrogen protection, add halogenated compound (32.8g, 0.1mol, 1eq), deuterated phenylboronic acid (12.6g, 0.1mol, 1eq), 300ml toluene, 100ml ethanol, potassium carbonate (41.4g, 0.3mol, 3eq), and 100ml water to the reaction flask. After the addition is completed, heat and reflux for 4h to complete the reaction. After post-treatment, add water to the reaction solution, separate the liquids, and concentrate the organic phase to dryness to obtain about 22.64g of the intermediate product 54-T, with a yield of about 80%.

[0107] S-1: Add intermediate 1 (22.64 g, 0.08 mol, 1 eq) to the reaction flask, add 200 ml of o-dichlorobenzene, and triphenylphosphine (41.92 g, 0.16 mol, 2 eq), and heat to reflux for 4 h. The reaction is complete. After post-treatment, o-dichlorobenzene is evaporated, and the crude product is subjected to column chromatography to obtain about 12 g of intermediate product 54-O, with a yield of about 60%.

[0108] S0: Under nitrogen protection, add halide (12g, 0.048mol, 1eq) to the reaction bottle, dry THF 200ml, cool to -78°C, add 1.6M n-butyl lithium (61.5ml, 0.0984mol, 2.05eq), keep stirring at -78°C for 1h after the addition is complete, add heavy water (200g, 10mol, 208eq), naturally warm to room temperature and stir for 12h. After post-treatment, add water to the reaction solution, separate the liquids, and concentrate the organic phase to dryness to obtain about 6.6g of the intermediate product 54-f with a yield of about 80%.

[0109] Compound 1-h was replaced by compound 54-h, and the final yield of compound 128 was 53.2%, ESI-MS (m / z) (M+): theoretical value 733.93, measured value 733.90, elemental analysis results (molecular formula C54H31D5N2O): theoretical value C, 88.37; H, 5.63; N, 3.82; O, 2.18; measured value C, 88.40; H, 5.58; N, 3.82; O, 2.20.

[0110] The following product compounds were obtained in a similar manner:

[0111] Table 4

[0112]

[0113]

[0114]

[0115] The synthesis and identification results of the compounds prepared in Tables 1 to 4 above are shown in Table 5 below:

[0116] Table 5

[0117]

[0118]

[0119]

[0120] Device performance test:

[0121] The organic electroluminescent compounds 6, 8, 9, 10, 12, 13, 17, 18, 21, 22, 26, 29, 31, 35, 37, 38, 39, 42, 46, 49, 52, 53, 55, 60, 62, 64, 68, 70, 75, 87, 88, 93, 95, 97, 99, 108, 109, 113 in Examples 1-66 of the present invention were tested. , 114, 115, 117, 119, 122, 125, 128, 130, 131, 133, 135, 139, 142, 144, 152, 155, 161, 165, 171, 174, 177, 179, 180, 185, 187, 192, 194, 196, the glass transition temperature Tg, thermal weight loss temperature Td, the results are shown in Table 6:

[0122] Note: Thermogravimetric temperature Td is the temperature at which the weight loss is 5% in a nitrogen atmosphere, and is measured on a TGA N-1000 thermogravimetric analyzer with a nitrogen flow rate of 10 mL / min. The glass transition temperature Tg is measured by differential scanning calorimetry (DSC, Shinco DSC N-650) with a heating rate of 10°C / min.

[0123] Table 6:

[0124]

[0125]

[0126] It can be seen from Table 6 above that the organic electroluminescent compound of the present invention has a relatively high Tg value and Td value, indicating that it has excellent thermal stability. Applying it to an organic electroluminescent device can effectively prolong the service life of the organic electroluminescent device and obtain a better use effect.

[0127] Device performance test:

[0128] Application Example 1:

[0129] ITO was used as the reflective layer anode substrate material, and water, acetone, N 2 Plasma treatment of its surface;

[0130] On top of the ITO anode substrate, HAT-CN with a thickness of 10 nm was deposited to form a hole injection layer (HIL);

[0131] A hole transport layer (HTL) was formed by evaporating 100 nm of HT-1 on the hole injection layer (HIL);

[0132] The organic electroluminescent compound 9 prepared in Example 1 of the present invention is vacuum-deposited on the hole transport layer (HTL) to form an electron blocking layer (EBL) with a thickness of 10 nm;

[0133] BH-1 as a blue light host material and BD-1 as a blue light doping material (the amount of BD-1 is 5% of the weight of ADN) are evaporated at different rates on the hole transport layer (HTL) to form a light-emitting layer with a thickness of 20 nm;

[0134] HB-1 was evaporated onto the light-emitting layer to obtain a hole blocking layer (HBL) with a thickness of 20 nm;

[0135] ET-1 was used as an electron transport layer material (ET) and evaporated onto the hole blocking layer (HBL) to obtain an electron transport layer (ETL) with a thickness of 30 nm. LiQ was evaporated on the electron transport layer (ETL) with a thickness of 2 nm to form an electron injection layer (EIL).

[0136] Thereafter, magnesium (Mg) and silver (Ag) are mixed in a ratio of 9:1 and evaporated to obtain a cathode with a thickness of 15 nm, and a DNTPD with a thickness of 50 nm is deposited on the cathode sealing layer. In addition, the cathode surface is sealed with a UV curable adhesive and a sealing film (seal cap) containing a dehumidifier to protect the organic electroluminescent device from being affected by oxygen or moisture in the atmosphere. Thus, an organic electroluminescent device is prepared.

[0137]

[0138] In D1: In D2: Application Example 2-66

[0139] The organic electroluminescent compounds 6, 8, 10, 12, 13, 17, 18, 21, 22, 26, 29, 31, 35, 37, 38, 39, 42, 46, 49, 52, 53, 55, 60, 62, 64, 68, 70, 75, 87, 88, 93, 95, 97, 99, 108, 109, 113, 114, 115, 117, 118, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 155, 156, 157, 158, 159, 160, 161, 162 9, 122, 125, 128, 130, 131, 133, 135, 139, 142, 144, 152, 155, 161, 165, 171, 174, 177, 179, 180, 185, 187, 192, 194, 196 replace the organic electroluminescent compound 9 in Application Example 1, and the other parts are consistent with Application Example 1, and the organic electroluminescent devices of Application Examples 2-66 are manufactured based on this.

[0140] Comparison example

[0141] The difference between the control example and application example 1 is that compounds 1, 61, 62 and 136 in patent CN111732578A (D1) and compounds 1, 4, 7 and 16 in CN113527271A (D2) are used to replace the organic electroluminescent compound 9 in application example 1, and the rest is the same as application example 1.

[0142] The organic electroluminescent devices prepared in Application Examples 1-66 and the Control Example were tested respectively, and the test results are shown in Table 7.

[0143] Table 7:

[0144]

[0145]

[0146]

[0147]

[0148] It can be seen from Table 7 above that applying the organic electroluminescent compound of the present invention to an organic electroluminescent device as an electron blocking layer (EBL) can significantly improve the luminous efficiency of the organic electroluminescent device, reduce the starting voltage, and relatively reduce power consumption.

[0149] The organic electroluminescent devices prepared in the control example and application examples 1-5, 35-39, 46-50 were tested for luminescence lifetime to obtain luminescence lifetime T97% data (the time when the luminescence brightness decreases to 97% of the initial brightness). The test equipment was a TEO luminescent device lifetime test system. The results are shown in Table 8:

[0150] Table 8:

[0151]

[0152]

[0153] It can be seen from Table 8 above that when the organic electroluminescent compound of the present invention is used as an electron blocking layer (EBL) in an organic electroluminescent device, the service life of the prepared organic electroluminescent device is greatly improved, so it has a very broad application prospect.

Claims

1. An organic electroluminescent compound, characterized in that: Its structural formula is shown in Formula 1 below: At least one of R1, R2, R3, R4, R5, R6, R7, and R8 is deuterium, and the rest are hydrogen. 10 is hydrogen or deuterium; m, o are 0; n is 1; Ar1 is an unsubstituted biphenyl group; Ar2 is a substituted or unsubstituted dibenzofuranyl group; The dibenzofuranyl group is unsubstituted or a group in which at least one hydrogen atom is substituted by a phenyl group.

2. The organic electroluminescent compound according to claim 1, characterized in that Its structural formula is shown in Formula 2, Formula 3 or Formula 4 below: Here R1-R 10 , m, o, n, Ar1, and Ar2 have the same meanings as in claim 1.

3. The organic electroluminescent compound according to claim 1, characterized in that The organic electroluminescent compound is any one of the following compounds:

4. An organic electroluminescent device, characterized in that: The invention comprises a first electrode, a second electrode and an organic layer formed between the first electrode and the second electrode, wherein the organic layer contains the organic electroluminescent compound according to any one of claims 1 to 3.

5. The organic electroluminescent device according to claim 4, characterized in that: The organic layer comprises a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; at least one of the hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, and electron injection layer contains the organic electroluminescent compound described in any one of claims 1 to 3.

6. The organic electroluminescent device according to claim 5, characterized in that: The electron blocking layer contains the organic electroluminescent compound according to any one of claims 1 to 3.

Images