Organic electroluminescent compound and electroluminescent device

Abstract

The invention discloses an organic electroluminescent compound and an electroluminescent device, the organic electroluminescent compound has a structure as shown in a formula (1-1) or (1-2), and can be applied to organic layers such as a luminescent layer of the device. The combined material formed by the N-type compound and the P-type compound with the carbazole structure as the core has good P / N proportion stability and mass production stability in the evaporation process, and the formed Premix material has balanced carrier mobility, so that the service life of a device is prolonged, the luminous efficiency of the device is improved, and the yield of a production line is improved. Meanwhile, compared with existing similar compounds, the N-type compound designed by the invention can be better matched with a P-type compound taking a carbazole structure as a core, and the organic electroluminescent device with higher luminous efficiency and longer service life can be prepared.

Description

Technical Field

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

[0002] Organic electroluminescence (OLED) refers to the luminescence phenomenon produced by carrier injection into a light-emitting layer made of organic materials under the action of an electric field, and is commonly used for display. The structure of an OLED device includes a cathode, an anode, and an organic layer disposed between the cathode and the cathode. The organic layer generally includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. For an OLED device with these layers, a voltage is applied between the two electrodes. Holes are injected from the anode into the organic layer, and electrons are injected from the cathode into the organic layer. When the holes and electrons meet, excitons are formed, which excite the luminescent material and ultimately produce visible light.

[0003] In organic electroluminescent devices, excellent material combinations must achieve synergistic optimization in multiple aspects, such as energy transfer and stability. Poor compatibility between materials can lead to inefficient energy transfer to the dopant, resulting in a decrease in device luminescence efficiency or even suboptimal performance. Consequently, researchers in this field are focused on developing new materials or optimizing material combinations within devices to further enhance device performance. Summary of the Invention

[0004] The technical purpose of the present invention is to develop materials for organic electroluminescent devices, especially N-type host materials that can be used in the light-emitting layer of the device and form a good match with P-type host materials with a carbazole structure as the core.

[0005] To achieve the above objectives, the technical solutions provided by the present invention are:

[0006] An organic electroluminescent compound, characterized by having a structure represented by formula (1-1) or formula (1-2):

[0007]

[0008] In formula (1-1) and formula (1-2):

[0009] X is CR1R2, wherein R1 and R2 are each independently selected from C1-C4 alkyl, deuterated or non-deuterated C1-C12 aryl;

[0010] R3, R4, R5 and R6 are deuterium, a is selected from an integer of 0-5, b and c are each independently selected from an integer of 0-2, and d is selected from an integer of 0-3;

[0011] One of Ar1 and Ar2 is selected from a deuterated or non-deuterated C6-C12 aromatic group, and the other is selected from a group represented by formula (2-1) or a group represented by a combination of formula (2-1) and formula (2-2);

[0012]

[0013] In formula (2-1) and formula (2-2):

[0014] R9 and R 10 Each independently represents deuterium, deuterated or non-deuterated C6-C12 aryl, R 11 represents deuterium;

[0015] * represents a linking site, n and p are each independently an integer selected from 0-4, and m is an integer selected from 0-3;

[0016] d1-d8 are used to illustrate the sites of formula (2-1), and the groups shown in formula (2-2) are connected to a pair of adjacent sites in d1-d8 by fusion.

[0017] As a more preferred embodiment, the group selected from deuterated or non-deuterated C6-C12 aromatic groups in Ar1 and Ar2 is phenyl or deuterated phenyl.

[0018] As a more preferred embodiment, R1 and R2 are the same or different and are selected from methyl, phenyl or deuterated phenyl.

[0019] As a more preferred embodiment, when Ar1 or Ar2 is selected from the group represented by the combination of formula (2-1) and formula (2-2), R9 and R 10 None of them are deuterated or non-deuterated C6-C12 aryl groups.

[0020] As a more preferred embodiment, the group represented by formula (2-1) or the group represented by the combination of formula (2-1) and formula (2-2) is selected from any one of the following groups which are substituted or unsubstituted with deuterium:

[0021]

[0022]

[0023] As a more preferred embodiment, formula (1) is represented by any one of formulas (1-1) to (1-6):

[0024]

[0025] In the above formula, R7 and R8 are deuterium, and e and f are each independently selected from integers of 0-5.

[0026] As a more preferred embodiment, the compound of the present invention is selected from at least one of the following compounds:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] An electroluminescent device comprises an anode, a cathode and an organic layer formed between the anode and the cathode, wherein the organic layer contains the organic electroluminescent compound described in any one of the above items.

[0039] Furthermore, the organic layer comprises a light-emitting layer, and the light-emitting layer contains the organic electroluminescent compound as described in any one of the above items.

[0040] Furthermore, the light-emitting layer contains a first host compound and a second host compound, the first host compound is selected from the organic electroluminescent compound described in any one of the above items, and the second host compound is selected from a compound formed by 0-2 groups represented by formula (4-1) and 0-2 groups represented by formula (4-2) fused and connected to the group represented by formula (3);

[0041]

[0042] In the above formula:

[0043] * represents the connection site. When the group represented by formula (4-1) or formula (4-2) is fused with the group represented by formula (3), it is connected to the adjacent site on the benzene ring A or benzene ring B;

[0044] L1 is a direct bond, phenyl or biphenyl;

[0045] Ar3 is a C6-C20 aryl group or a C5-C20 heteroaryl group;

[0046] Y, when present in each case, is the same or different and represents O, S or NAr5, and Ar5 is selected from C6-C20 aryl or C5-C20 heteroaryl.

[0047] Furthermore, the second host material compound is selected from compounds having structures shown in formula (5-1), (5-2) or (5-3):

[0048]

[0049] Wherein, Ar4 is selected from a C6-C20 aryl group or a C5-C20 heteroaryl group.

[0050] Furthermore, the second host material compound is selected from at least one of the following compounds:

[0051]

[0052]

[0053]

[0054] Beneficial effects

[0055] 1) The composite material formed by the N-type compound designed in the present invention and the P-type compound with a carbazole structure as the core has good P / N ratio stability and mass production stability during the vapor deposition process. The formed premix material has balanced carrier mobility, thereby improving the device life and luminous efficiency, as well as the production yield.

[0056] 2) Compared with existing similar compounds, the N-type compound designed in the present invention can form a better combination with the P-type compound with a carbazole structure as the core, thereby preparing an organic electroluminescent device with higher luminous efficiency and longer life. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a schematic structural diagram of the organic electroluminescent device provided by the present invention;

[0058] Figure 2 It is the HPLC chart of compound N-1 of the present invention.

[0059] Figure 3 It is the TGA spectrum of compound N-1 of the present invention.

[0060] Figure 4 It is the DSC spectrum of compound N-1 of the present invention.

[0061] Figure 1The reference numerals in the figures represent: 1-anode, 2-hole injection layer, 3-first hole transport layer, 4-second hole transport layer, 5-light-emitting layer, 6-hole blocking layer, 7-electron transport layer, 8-electron injection layer, 9-cathode. DETAILED DESCRIPTION

[0062] In order to further illustrate the technical solution of the present invention, the present invention is described in more detail below with reference to specific embodiments.

[0063] Unless otherwise specified, the "aryl" in the specification refers to a group containing one or more aromatic rings, including but not limited to benzene, naphthalene, phenanthrene, fluorene, acenaphthene, etc. The "heteroaryl" in this article refers to a heteroaryl group obtained by replacing one or more C in the "aryl" structure with one or more heteroatoms (such as N, O, S, etc.).

[0064] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0065] Example 1:

[0066]

[0067] Taking compound N-1 as an example, its synthesis process is as follows:

[0068] 1.1) Preparation of ZJ1

[0069]

[0070] Under N2 protection, SM1 (142.59 g, 1 mol, 1 eq), SM2 (148.21 g, 1 mol, 1 eq) and acetic acid (1500 ml) were added to a 3 L three-necked flask, and the temperature was raised to 170 °C and stirred for 17 h.

[0071] The reaction was stopped, the temperature was lowered to room temperature, the solid was precipitated, filtered, the filter cake was rinsed with water, the solid was dried, dissolved in DCM, sand made, column chromatography, PE / DCM = 50 / 1~25 / 1~20 / 1~15 / 1~10 / 1~5 / 1, the product points were collected, concentrated to dryness under reduced pressure, pure PE was added and stirred for 30 min, filtered, and the filter cake was air-dried at 85°C to obtain 80 g of off-white solid ZJ1 with a yield of 31.3%.

[0072] 1.2) Preparation of ZJ2

[0073]

[0074] To a 1 L three-necked flask, ZJ1 (80 g, 0.313 mol, 1 eq), pinacol diboron (103.3 g, 0.407 mol, 1 eq), potassium acetate (92.2 g, 0.939 mol, 3 eq), XPhos (8.95 g, 18.78 mmol, 0.06 eq), and 1,4-dioxane were added. Under N2 protection, Pd2(dba)3 (8.6 g, 9.39 mmol, 0.06 eq) was added. The temperature was raised to 110°C and the reaction was stirred. ZJ1 was monitored by HPLC to be ≤1%.

[0075] Stop the reaction, filter through silica gel while hot, rinse the filter cake with DCM, concentrate the filtrate to dryness under reduced pressure, add pure PE, cool and stir to crystallize for 3 hours, filter, and air dry the filter cake at 85°C to obtain 78g of gray solid ZJ2 with a yield of 71.6%.

[0076] 1.3) Preparation of ZJ3

[0077]

[0078] To a 3 L three-necked flask, ZJ2 (78 g, 0.225 mol, 1 eq), SM3 (71.3 g, 0.225 mol, 1 eq), potassium carbonate (62.2 g, 0.45 mol, 2 eq), and toluene / ethanol / water (1600 ml + 800 ml + 480 ml) were added. Under N2 protection, tetrakistriphenylphosphine palladium (5.2 g, 4.5 mmol, 0.02 eq) was added. The temperature was raised to reflux with stirring, and the reaction was monitored by HPLC to ensure that ZJ2 was ≤1%.

[0079] The reaction was stopped, water was added and stirred to separate the liquids, the aqueous phase was extracted with DCM, the organic phases were combined, and the mixture was concentrated under reduced pressure to dryness. 100 g of 100-200 mesh silica gel sand was added, and 800 g of 100-200 mesh silica gel was loaded into a column for column chromatography. The product spots were collected and concentrated under reduced pressure to dryness. PE was added and stirred to crystallize. The mixture was filtered with suction, and the filter cake was air-dried at 85°C to obtain 70 g of an off-white solid ZJ3 with a yield of 75.8%.

[0080] 1.4) Preparation of ZJ4

[0081]

[0082] To a 2 L three-necked flask, ZJ3 (70 g, 0.17 mol, 1 eq), SM4 (40.2 g, 0.409 mol, 2.4 eq), cuprous iodide (0.97 g, 5.1 mmol, 0.03 eq), triphenylphosphine (4.46 g, 0.017 mol, 0.1 eq), and triethylamine (700 ml) were added. Under N2 protection, PdCl2(dppf) (3.73 g, 5.1 mmol, 0.03 eq) was added. The reaction was stirred at reflux and the temperature was raised. ZJ3 was monitored by HPLC until ≤1%.

[0083] The reaction was stopped and concentrated under reduced pressure to remove most of the triethylamine. Water and DCM were added and stirred to separate the liquids. The aqueous phase was extracted with DCM. The organic phases were combined and concentrated to dryness under reduced pressure. 100 g of 100-200 mesh silica gel sand was added and 700 g of 100-200 mesh silica gel was loaded on a column for column chromatography. The product spots were collected and concentrated to dryness under reduced pressure to obtain 63.2 g of oily solid ZJ4 with a yield of 86.8%.

[0084] 1.5) Preparation of ZJ5

[0085]

[0086] ZJ4 (63.2 g, 0.148 mol, 1 eq) and THF (600 ml) were added to a 2 L single-necked flask, followed by 1.0 M TBAF solution (197 ml, 0.197 mol, 1.33 eq). The mixture was stirred at room temperature for 1-2 h. ZJ4 was essentially eliminated by TLC monitoring.

[0087] The reaction was stopped, and water was added with stirring to quench the reaction. EA was added with stirring to extract. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated to dryness under reduced pressure and used directly in the next reaction without purification.

[0088] 1.6) ZJ6 preparation

[0089]

[0090] ZJ5 (theoretical 52.7 g, 0.148 mol, 1 eq) and toluene (500 ml) were added to a 1 L three-necked flask. Under N2 protection, platinum dichloride (3.94 g, 0.0148 mol, 1.33 eq) was added. The temperature was raised to reflux with stirring, and the reaction was monitored by HPLC until ZJ5 ≤ 1%.

[0091] The reaction was stopped and filtered through silica gel while hot. The filtrate was concentrated to dryness under reduced pressure, 60 g of 100-200 mesh silica gel sand was added, and 500 g of 100-200 mesh silica gel was loaded into a column for column chromatography. The product spots were collected and concentrated to dryness under reduced pressure. PE was added and stirred for crystallization. The product was filtered and the filter cake was dried at 85°C with air to obtain 30.2 g of an off-white solid ZJ6 with a yield of 57.3%.

[0092] 1.7) ZJ7 preparation

[0093]

[0094] To a 1 L three-necked flask, ZJ6 (30.2 g, 84.9 mmol, 1 eq), pinacol diboron (28 g, 0.11 mol, 1 eq), potassium acetate (25 g, 0.2547 mol, 3 eq), XPhos (2.43 g, 5.094 mmol, 0.06 eq), and 1,4-dioxane were added. Under nitrogen protection, Pd2(dba)3 (2.33 g, 2.547 mmol, 0.06 eq) was added. The temperature was raised to 110°C and the reaction was stirred. ZJ6 was monitored by HPLC until ≤1%.

[0095] Stop the reaction, filter through silica gel while hot, rinse the filter cake with DCM, concentrate the filtrate to dryness under reduced pressure, add pure PE, cool and stir to crystallize for 3 hours, filter, and air dry the filter cake at 85°C to obtain 27.8 g of gray solid ZJ7 with a yield of 73.2%.

[0096] 1.8) Preparation of target product TM

[0097]

[0098] To a 1 L three-necked flask, ZJ7 (27.8 g, 62.1 mmol, 1.03 eq), SM5 (21.57 g, 60.3 mol, 1 eq), potassium carbonate (16.7 g, 0.1206 mol, 2 eq), and toluene / ethanol / water (300 ml + 150 ml + 90 ml) were added. Under N2 protection, tetrakistriphenylphosphine palladium (1.39 g, 1.206 mmol, 0.02 eq) was added. The temperature was raised to reflux with stirring, and the reaction was monitored by HPLC until ZJ5 ≤ 1%.

[0099] Stop the reaction, add water, stir and cool to room temperature, filter, and dry the filter cake at 85°C. Dissolve the filter cake with toluene and filter it while hot through silica gel. After most of the toluene is evaporated from the filtrate, cool it to room temperature and crystallize for 1 hour. Filter it with suction. Recrystallize the filter cake with toluene 5 times, evaporate 2 / 3 of the toluene each time, cool it and crystallize it. Filter it with suction and dry the filter cake at 85°C to obtain 18.9g of off-white solid with a yield of 48.8%.

[0100] Example 2:

[0101]

[0102] This example takes compound N-193 as an example, and its synthesis route is as follows:

[0103]

[0104] The preparation process of ZJ6 is the same as that of Example 1. The preparation process from ZJ7' to the target product TM' can refer to the preparation process from ZJ7 to TM in Example 1. SM5' is SM5 that has been deuterated. The preparation of this example differs significantly from that of Example 1 in the preparation of ZJ6'.

[0105] The preparation process of ZJ6' is as follows:

[0106] Add ZJ6 (30.2 g, 84.9 mmol, 1 eq) and deuterated benzene (143 g, 1.7 mol, 20 eq) to a 1 L three-necked flask, cool to 0°C, and slowly add trifluoromethanesulfonic acid (153 g, 1.02 mol, 12 eq) dropwise while controlling the internal temperature to ≤20°C. After completion of the addition, heat to 50°C and stir for 24 h.

[0107] Stop the reaction, cool to below 0°C, slowly add 30 ml of heavy water to quench and stir for 30 min, add 600 ml of water, a large amount of solid precipitates, filter, rinse the filter cake with water, and dry the filter cake at 85°C to obtain 29.5 g of gray solid ZJ6', with a yield of 94.6%.

[0108] Then, a synthetic route similar to that in Example 1 was adopted to prepare the target product TM' of this example using ZJ6'.

[0109] Example 3:

[0110]

[0111] This example takes compound N-189 as an example, and its synthesis route is as follows:

[0112]

[0113] The preparation process of ZJ2 is the same as that of Examples 1 and 2. The preparation process from ZJ7" to the target product TM" can refer to the preparation process from ZJ7' to TM' in Example 2. The synthetic step in this example that is significantly different from that in Example 2 is the preparation from ZJ2 to ZJ6-3".

[0114] The preparation process of ZJ6-3" is as follows:

[0115] 2.2) Preparation of ZJ3"

[0116]

[0117] To a 3 L three-necked flask, ZJ2 (78 g, 0.225 mol, 1 eq), SM3 (74.8 g, 0.225 mol, 1 eq), potassium carbonate (62.2 g, 0.45 mol, 2 eq), and toluene / ethanol / water (1600 ml + 800 ml + 480 ml) were added. Under N2 protection, tetrakistriphenylphosphine palladium (5.2 g, 4.5 mmol, 0.02 eq) was added. The temperature was raised to reflux with stirring, and the reaction was monitored by HPLC until ZJ2 was ≤1%.

[0118] The reaction was stopped, water was added and stirred to separate the liquids, the aqueous phase was extracted with DCM, the organic phases were combined and concentrated to dryness under reduced pressure, 100 g of 100-200 mesh silica gel sand was added, 800 g of 100-200 mesh silica gel was loaded into a column, column chromatography was performed, the product spots were collected, and the product was concentrated to dryness under reduced pressure. PE was added and stirred to crystallize, and the filter cake was filtered and dried with air at 85°C to obtain 85 g of an off-white solid ZJ3", with a yield of 88.7%.

[0119] 2.3) Preparation of ZJ4

[0120]

[0121] To a 2L three-necked flask, ZJ3" (85g, 0.2mol, 1eq), SM4" (47g, 0.48mol, 2.4eq), cuprous iodide (1.14g, 6mmol, 0.03eq), triphenylphosphine (5.25g, 0.02mol, 0.1eq) and triethylamine (700ml) were added. Under N2 protection, PdCl2(dppf) (4.39g, 6mmol, 0.03eq) was added. The temperature was raised to reflux with stirring, and the reaction was monitored by HPLC until ZJ3" ≤ 1%.

[0122] The reaction was stopped and concentrated under reduced pressure to remove most of the triethylamine. Water and DCM were added, stirred, and the liquids were separated. The aqueous phase was extracted with DCM. The organic phases were combined and concentrated to dryness under reduced pressure. 100 g of 100-200 mesh silica gel was added and loaded onto a column with 700 g of 100-200 mesh silica gel. Column chromatography was performed and the product was collected. The product was concentrated under reduced pressure to dryness to obtain 79 g of an off-white solid ZJ4", with a yield of 89.2%.

[0123] 2.4) Preparation of ZJ5

[0124]

[0125] ZJ4" (79 g, 0.178 mol, 1 eq) and THF (800 ml) were added to a 2 L single-necked flask, and 1.0 M TBAF solution (237 ml, 0.237 mol, 1.33 eq) was added. The reaction was stirred at room temperature for 1-2 h. After the TLC monitoring showed that ZJ4" had basically disappeared, the reaction was stopped. Water was added with stirring to quench the reaction. EA was added with stirring and extracted. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated to dryness under reduced pressure. The product ZJ5" was used directly in the next reaction without purification.

[0126] 2.5) Preparation of ZJ6-1"

[0127]

[0128] Add ZJ5" (theoretical 66 g, 0.178 mol, 1 eq) and toluene (500 ml) to a 1 L three-necked flask. Under N2 protection, add platinum dichloride (4.73 g, 0.0178 mol, 0.1 eq). Heat and reflux with stirring to react. Monitor ZJ5" by HPLC until it is ≤1%.

[0129] Stop the reaction, filter through silica gel while hot, concentrate the filtrate under reduced pressure to dryness, add 60 g of 100-200 mesh silica gel sand, and load 500 g of 100-200 mesh silica gel into a column for column chromatography. Collect the product points, concentrate under reduced pressure to dryness, add PE, stir and crystallize, filter with suction, and dry the filter cake at 85°C with air to obtain 51.5 g of off-white solid ZJ6-1", with a yield of 78%.

[0130] 2.6) Preparation of ZJ6-2"

[0131]

[0132] Add ZJ6-1 (51.5 g, 0.139 mol, 1 eq) and deuterated benzene (235 g, 2.78 mol, 20 eq) to a 2 L three-necked flask, cool to 0°C, and slowly add trifluoromethanesulfonic acid (253 g, 1.668 mol, 12 eq) dropwise while controlling the internal temperature to ≤ 20°C. After the addition is complete, heat to 50°C and stir for 24 h.

[0133] Stop the reaction, cool to below 0°C, slowly add 50 ml of heavy water dropwise to quench and stir for 30 min, add 900 ml of water, a large amount of solid precipitates, filter, rinse the filter cake with water, and dry the filter cake at 85°C to obtain 49.15 g of gray solid ZJ6-2", with a yield of 92.6%.

[0134] 2.7) Preparation of ZJ6-3"

[0135]

[0136] Add ZJ6-2 (49 g, 0.128 mol, 1 eq) and 250 ml of the solution into a 1 L three-necked flask, cool to below 0°C, slowly add concentrated hydrochloric acid (21.3 ml, 0.256 mol, 2 eq) dropwise, stir and react for 30 min, add a solution of sodium nitrite (44.16 g, 0.64 mol, 5 eq) in water (50 ml), add 100 ml of ethanol, heat to 80°C and stir and react for 8 h;

[0137] Stop the reaction, add DCM (200 ml * 2) to the aqueous phase and extract twice. Combine the organic phases and concentrate under reduced pressure to dryness. Add 60 g of 100-200 mesh silica gel sand and load 600 g of 100-200 mesh silica gel on a column for column chromatography. Collect the product points and concentrate under reduced pressure to dryness to obtain 26 g of off-white solid ZJ6-3", with a yield of 57%.

[0138] Afterwards, a synthetic route similar to that in Example 2 was adopted to prepare the target product TM using ZJ6-3".

[0139] The following compounds were prepared in a similar manner to those of Examples 1-3, as shown in Table 1.

[0140] Table 1

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150] The synthesis and identification results of the compounds prepared by the above method are shown in Table 2 below.

[0151] Table 2

[0152]

[0153]

[0154] The basic performance tests were carried out on the above-synthesized compounds, and the thermal weight loss temperature Td and glass transition temperature Tg of the materials were tested respectively. The test results are shown in Table 3 below.

[0155] Table 3

[0156]

[0157]

[0158] Note: Thermogravimetric temperature (Td) is the temperature at which the weight loss is 5% in a nitrogen atmosphere, and was measured on a TGA N-1000 thermogravimetric analyzer with a nitrogen flow rate of 10 mL / min. The glass transition temperature (Tg) was measured by differential scanning calorimetry (DSC, Xinke DSC N-650) with a heating rate of 10°C / min.

[0159] From the above data, it can be seen that the above synthesized compounds have excellent thermal stability and can meet the requirements for use as organic electroluminescent materials.

[0160] Device performance test:

[0161] Application Example 1:

[0162] ITO was used as the reflective layer anode substrate material, and its surface was treated with water, acetone, and N2 plasma in sequence;

[0163] On top of the ITO anode substrate, 10 nm of HT-1 doped with 3% NDP-9 was deposited to form a hole injection layer (HIL);

[0164] A first hole transport layer (HTL) was formed by evaporating 100 nm of HT-1 on the hole injection layer (HIL); a second hole transport layer (HTL) was formed by vacuum evaporating HT-2 on the first hole transport layer (HTL) to a thickness of 10 nm;

[0165] The compound (N-type) prepared in Example 1 of the present invention and the compound P-4 (P-type) were used as the luminescent host materials, with the weight ratio of N-1 to P-4 being 6:4. RD-1 was used as the doping material (the amount of RD-1 was 3% of the total weight of the compound N-1 and the compound P-4). Co-evaporation was performed to form a 30 nm thick luminescent layer on the second hole transport layer.

[0166] HB-1 was evaporated onto the light-emitting layer to obtain a hole blocking layer (HBL) with a thickness of 20 nm;

[0167] ET-1 and LiQ were co-evaporated onto the hole blocking layer (HBL) in a weight ratio of 5:5 to obtain an electron transport layer (ETL) with a thickness of 30 nm;

[0168] Magnesium (Mg) and silver (Ag) were mixed and evaporated on the electron transport layer (ETL) in a weight ratio of 9:1 to form an electron injection layer (EIL) with a thickness of 50 nm.

[0169] Silver (Ag) is then evaporated onto the electron injection layer to form a 100nm-thick cathode. A 50nm-thick layer of DNTPD is deposited on the cathode sealing layer. Furthermore, the cathode surface is sealed with a UV-curable adhesive and a seal cap containing a desiccant to protect the organic electroluminescent device from atmospheric oxygen or moisture. Thus, an organic electroluminescent device is prepared.

[0170] Application Example 2-47:

[0171] Then, compounds N-2 to N-202 in Table 3 of the present invention were used as one of the main materials, and P4, P8, P13 or P24 was used as the other main material. The other parts were the same as those in Application Example 1, and the organic electroluminescent devices of Application Example 2-47 were produced accordingly.

[0172] Other compounds used in the above examples or comparative examples are as follows:

[0173]

[0174] Comparative Examples 1-6: The existing compounds J1, J2, and J3 were used instead of compound N-1 as one of the main materials of the light-emitting layer, and P4, P8, P13, or P24 was used as the other main material. The organic electroluminescent devices of Comparative Examples 1-6 were prepared under the same conditions as in Application Example 1.

[0175]

[0176] The characteristics of the organic electroluminescent device manufactured in the above application example and the organic electroluminescent device manufactured in the comparative example are that the current density is 10mA / cm 2 The results are shown in Table 4 below.

[0177] Table 4

[0178]

[0179]

[0180]

[0181] As can be seen from Table 4 above, when the compound of the present invention is used as one of the host materials (N-type) in the light-emitting layer of an organic electroluminescent device, compared to the N-type host material used in the prior art, when paired with the same P-type host material, the driving voltage of the organic electroluminescent device in the application example of the present invention is significantly reduced at the same current density, and the luminous efficiency is improved.

[0182] Then, the organic electroluminescent devices prepared in the control examples 1-6 and some application examples were selected for luminescence lifetime test to obtain the luminescence lifetime T97% data (the time when the luminescence brightness drops to 97% of the initial brightness). The test equipment was the TEO light emitting device lifetime test system, and the test conditions were a current density of 10 mA / cm 2 Taking the lifespan data of Control Example 1 as a reference, the results are shown in Table 5:

[0183] Table 5

[0184] experimental group Main material T97％ experimental group Main material T97％ Comparative Example 1 J1+P4 100％ Application Example 19 N-89+P4 141％ Comparative Example 2 J2+P4 119％ Application Example 22 N-98+P4 138％ Comparative Example 3 J3+P4 102％ Application Example 24 N-110+P13 145％ Comparative Example 4 J1+P8 95％ Application Example 26 N-118+P13 148％ Comparative Example 5 J2+P13 110％ Application Example 27 N-121+P4 139％ Comparative Example 6 J3+P24 104％ Application Example 29 N-130+P4 138％ Application Example 1 N-1+P4 141％ Application Example 31 N-138+P24 135％ Application Example 2 N-2+P4 138％ Application Example 33 N-150+P24 147％ Application Example 3 N-13+P4 146％ Application Example 34 N-154+P4 148％ Application Example 4 N-14+P4 148％ Application Example 35 N-162+P4 141％ Application Example 5 N-15+P4 151％ Application Example 37 N-173+P8 138％ Application Example 7 N-25+P8 143％ Application Example 39 N-177+P13 145％ Application Example 9 N-30+P4 149％ Application Example 41 N-186+P4 150％ Application Example 10 N-33+P4 151％ Application Example 42 N-189+P24 153％ Application Example 12 N-43+P4 157％ Application Example 43 N-190+P8 164％ Application Example 14 N-58+P4 147％ Application Example 45 N-194+P13 168％ Application Example 18 N-87+P8 161％ Application Example 46 N-197+P4 171％

[0185] As can be seen from Table 5, compared with existing similar compounds, the N-type compound provided by the embodiment of the present invention, when combined with the same P-type compound, has a significantly improved device service life at the same current density.

[0186] Combined with the above test examples, it can be seen that the main material of the light-emitting layer composed of the N-type compound designed in the present invention can form a good premix material with the P-type compound with carbazole as the core structure, thereby improving the luminous efficiency and service life of the device.

[0187] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An organic electroluminescent compound, characterized in that Having the structure shown in formula (1-1) or formula (1-2): In formula (1-1) and formula (1-2): X is CR1R2, wherein R1 and R2 are each independently selected from C1-C4 alkyl, deuterated or non-deuterated C1-C12 aryl; R3, R4, R5 and R6 are deuterium, a is selected from an integer of 0-5, b and c are each independently selected from an integer of 0-2, and d is selected from an integer of 0-3; One of Ar1 and Ar2 is selected from a deuterated or non-deuterated C6-C12 aromatic group, and the other is selected from a group represented by formula (2-1) or a group represented by a combination of formula (2-1) and formula (2-2); In formula (2-1) and formula (2-2): R9 and R 10 Each independently represents deuterium, deuterated or non-deuterated C6-C12 aryl, R 11 represents deuterium; * represents a linking site, n and p are each independently an integer selected from 0-4, and m is an integer selected from 0-3; d1-d8 are used to illustrate the sites of formula (2-1), and the groups shown in formula (2-2) are connected to a pair of adjacent sites in d1-d8 by fusion.

2. An organic electroluminescent compound according to claim 1, characterized in that The group selected from deuterated or non-deuterated C6-C12 aryl groups in Ar1 and Ar2 is phenyl or deuterated phenyl.

3. The organic electroluminescent compound according to claim 1, wherein R1 and R2 are the same or different and are selected from methyl, phenyl or deuterated phenyl.

4. The organic electroluminescent compound according to claim 1, wherein When Ar1 or Ar2 is selected from the group represented by the combination of formula (2-1) and formula (2-2), R9 and R 10 None of them are deuterated or non-deuterated C6-C12 aryl groups.

5. The organic electroluminescent compound according to claim 1, wherein The group represented by formula (2-1) or the group represented by the combination of formula (2-1) and formula (2-2) is selected from any one of the groups represented by formula (2-1) to formula (2-18) which are substituted or unsubstituted with deuterium:

6. The organic electroluminescent compound according to claim 1, wherein Formula (1) can be expressed by any one of Formulas (1-1) to (1-6): In the above formula, R7 and R8 are deuterium, and e and f are each independently selected from integers of 0-5.

7. The organic electroluminescent compound according to claim 1, wherein At least one selected from the following compounds:

8. An electroluminescent device comprising an anode, a cathode, and an organic layer formed between the anode and the cathode, characterized in that: The organic layer contains the organic electroluminescent compound according to any one of claims 1 to 7.

9. The electroluminescent device according to claim 8, wherein The organic layer comprises a light-emitting layer, and the light-emitting layer contains the organic electroluminescent compound according to any one of claims 1 to 7.

10. The electroluminescent device according to claim 9, wherein The light-emitting layer contains a first host compound and a second host compound, wherein the first host compound is selected from the organic electroluminescent compound according to any one of claims 1 to 8, and the second host compound is selected from a compound formed by 0-2 groups represented by formula (4-1) and 0-2 groups represented by formula (4-2) fused and connected to the group represented by formula (3); In the above formula: * represents the connection site. When the group represented by formula (4-1) or formula (4-2) is fused with the group represented by formula (3), it is connected to the adjacent site on the benzene ring A or benzene ring B; L1 is a direct bond, phenyl or biphenyl; Ar3 is a C6-C20 aryl group or a C5-C20 heteroaryl group; Y, when present in each case, is the same or different and represents O, S or NAr5, and Ar5 is selected from C6-C20 aryl or C5-C20 heteroaryl.

11. The electroluminescent device according to claim 10, wherein The second host material compound is selected from the compounds represented by formula (5-1), (5-2) or (5-3): in, Ar4 is selected from one of a C6-C20 aryl group and a C5-C20 heteroaryl group.

12. The electroluminescent device according to claim 10, wherein the second host material compound is at least one selected from the group consisting of:

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