A fused-ring compound and an organic electroluminescent device

Abstract

The present invention relates to the technical field of optoelectronic material applications, and discloses a polycyclic compound and an organic electroluminescent device thereof. By introducing a phenanthro-fused five-membered heterocyclic core structure with a relatively high triplet energy level and finely regulating the core structure using different types of electron donor-acceptor groups, the polycyclic compound provides a luminescent host material with excellent comprehensive performance, effectively solving the problems such as high driving voltage and low fluorescence quantum efficiency caused by difficult charge injection in current luminescent host materials, achieving the technical effect of balancing luminescence efficiency and driving voltage, and having significant application value as a luminescent host material in organic electroluminescent devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic material applications, and particularly relates to a polycyclic compound and an organic electroluminescent device thereof. Background Art

[0002] An organic electroluminescent device (OLED) is a self-luminous display device, and its advantages are that it can provide a wider viewing angle, a higher contrast ratio, and a faster response time. The structure of an organic electroluminescent device is similar to a "sandwich", and usually includes an anode, a cathode, and an organic layer formed between these two electrodes.

[0003] In an organic electroluminescent device, by applying a voltage, holes from the anode and electrons from the cathode can be injected into the light-emitting layer, and high-energy excitons are generated through the recombination of holes and electrons. Thus, the energy of the light-emitting layer compound molecules is activated and transformed into an excited state. When the light-emitting layer compound molecules return from the unstable excited state to the ground state, energy is released and light is emitted.

[0004] The most important factor determining the luminous efficiency of an organic electroluminescent device is the luminescent material. According to different luminescent colors, luminescent materials can be divided into blue, green, and red luminescent materials, and can further include yellow and orange luminescent materials. According to different functions, luminescent materials can be divided into host materials and guest materials. Regardless of the classification, excellent luminescent materials are required to have the following characteristics: high quantum efficiency, high electron and hole recombination rate, good uniformity and stability of the formed light-emitting layer. To meet the urgent need for currently preparing high-efficiency and long-life organic electroluminescent devices, it is imperative to develop luminescent materials with the above excellent properties. Summary of the Invention

[0005] The purpose of the present invention is to provide a host material that is highly efficient and stable and can be used in organic electroluminescent devices. When this host material is applied to organic electroluminescent devices, it can effectively solve problems such as high driving voltage and low luminous efficiency of current devices.

[0006] The first aspect of the present invention provides a polycyclic compound, and its compound has the structure shown in formula (I):

[0007]

[0008] Wherein, X and Y are each independently selected from N, N(R2), O or S, and one of X and Y is N, and the other of X and Y is selected from N(R2), O or S;

[0009] represents a single bond, located on the left or right side of the central axis of the five-membered ring, constituting a double bond in the five-membered heterocycle;

[0010] L0 is selected from a single bond, or a phenylene group unsubstituted or substituted by an alkyl group having C 1～20 , an alkoxy group having C 1～20 , a nitrile group, a nitro group, a fluorine group, or a phenylene group unsubstituted or substituted by an alkyl group having C 1～20 , an alkoxy group having C 1～20 , a nitrile group, a nitro group, a fluorine group, or a biphenylene group unsubstituted or substituted by an alkyl group having C 1～20 , an alkoxy group, a nitrile group, a nitro group, a fluorine group, or a naphthylene group unsubstituted or substituted by an alkyl group, an alkoxy group, a nitrile group, a nitro group, or a fluorine group;

[0011] R1 is selected from an alkyl group having C 1～20 , an aryl group having C 6～50 , or a heteroaryl group having C 3～50 ;

[0012] R0 is selected from one of the groups represented by the following A1, A2, A3, A4, or A5:

[0013]

[0014] Wherein,

[0015] Z is C, CH or N, the number of Z being N is 1, 2 or 3, and two adjacent Zs are not N at the same time. When Z is C, it is the substitution site of R0 bridging L0 or the substitution site of R3-R8;

[0016] Q1 is selected from O, S, N(R 11 ), C(R 12 )(R 13 );

[0017] Q2 is selected from N, P, P(=O);

[0018] Ar represents non-existence or a monocyclic aromatic hydrocarbon, and the Ar is directly fused with the connected naphthalene ring;

[0019] R2-R 13 are each independently selected from hydrogen, a fluorine group, a nitro group, a cyano group, an alkyl group having C 1-20 , a silyl group having C 1-20 , an aryl group having C 6-50 , a heteroaryl group having C 3-50 , an aryloxy group having C 6-50 , or an arylthio group having C 6-50 ;

[0020] Furthermore, R1 is selected from: a phenyl group unsubstituted or substituted by a methyl group, a methoxy group, a nitrile group, a nitro group, or a fluorine group, a biphenyl group unsubstituted or substituted by a methyl group, a methoxy group, a nitrile group, a nitro group, or a fluorine group, a naphthyl group unsubstituted or substituted by a methyl group, a methoxy group, a nitrile group, a nitro group, or a fluorine group.

[0021] Furthermore, R1 is a phenyl group.

[0022] Further, R2 is selected from: phenyl which is unsubstituted or substituted by a fluoro group, a nitro group, a cyano group, a C1-C6 alkyl group, or a C1-C6 alkoxy group; biphenyl which is unsubstituted or substituted by a fluoro group, a nitro group, a cyano group, a C1-C6 alkyl group, or a C1-C6 alkoxy group; naphthyl which is unsubstituted or substituted by a fluoro group, a nitro group, a cyano group, a C1-C6 alkyl group, or a C1-C6 alkoxy group.

[0023] Further, L0 is selected from a single bond, phenyl, biphenyl, and naphthyl.

[0024] Further, A1 can be further represented as:

[0025] A2 can be further represented as:

[0026] A3 can be further represented as:

[0027] A4 can be further represented as:

[0028] A5 can be further represented as:

[0029] Wherein,

[0030] Z1 is C, CH or N, the number of Z1 being N is 1, 2 or 3, and two adjacent Z1 are not N at the same time. When Z1 is C, it is the substitution site where R0 bridges L0 or the substitution site of R 21 、R 24 、R 25 ;

[0031] Q3 and Q4 are each independently selected from O, S, N(R 32 ), C(R 33 )(R 34 );

[0032] R 14 -R 34Independently selected from hydrogen, fluoro group, nitro group, cyano group, C1-C6 alkyl group, phenyl group unsubstituted or substituted by fluoro group, nitro group, cyano group, C1-C6 alkyl group, naphthyl group, biphenyl group unsubstituted or substituted by fluoro group, nitro group, cyano group, C1-C6 alkyl group, phenyl group, naphthyl group unsubstituted or substituted by fluoro group, nitro group, cyano group, C1-C6 alkyl group, phenyl group, dibenzofuran group unsubstituted or substituted by fluoro group, nitro group, cyano group, C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, dibenzothiophene group unsubstituted or substituted by fluoro group, nitro group, cyano group, C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, fluorene group unsubstituted or substituted by fluoro group, nitro group, cyano group, C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, carbazole group unsubstituted or substituted by fluoro group, nitro group, cyano group, C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, diphenylamine group.

[0033] Furthermore, It can be further represented as:

[0034] It can be further represented as:

[0035] Wherein, Z1 is CH or N, and the number of Z1 being N is 1, 2 or 3;

[0036] It can be further represented as: It can be further represented as:

[0037] It can be further represented as:

[0038]

[0039] It can be further represented as:

[0040]

[0041] Wherein, Q4 is independently selected from O, S, C(CH3)2, N(R 32 ), and R 32 is selected from phenyl group, tolyl group, tert-butylphenyl group, cyanophenyl group, nitrophenyl group, fluorophenyl group, biphenyl group, terphenyl group, naphthyl group;

[0042] It can be further expressed as:

[0043] It can be further expressed as:

[0044] It can be further expressed as:

[0045] It can be further expressed as:

[0046] It can be further expressed as:

[0047] Furthermore, the fused-ring compound shown in formula (I) is selected from the following compounds:

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] In the second aspect of the present invention, an organic electroluminescent device is provided, which mainly includes a cathode, an anode, and an organic layer between the two electrodes. The organic layer between the two electrodes contains any one of the above-mentioned fused-ring compounds.

[0054] Furthermore, the organic layer between the two electrodes includes a light-emitting layer, and the light-emitting layer is composed of a light-emitting host and a light-emitting guest, and the light-emitting host includes any one of the above-mentioned fused-ring compounds.

[0055] The molecular core structure of the polycyclic compound provided by the present invention contains a large conjugated planar structure of phenanthro-fused five-membered heterocycle, so it has a relatively high triplet energy level. When used as a host material, it can effectively prevent the energy back transfer during the light-emitting process, so that the compound material can obtain a higher fluorescence quantum efficiency. The introduction of phenyl groups in the core structure can effectively inhibit the intermolecular interaction and reduce the π-π stacking between compound molecules. In addition, introducing different types of hole-transporting groups or electron-transporting groups to modify the core structure can effectively improve the balance of holes and electrons in the light-emitting layer. When used as a host material, this can effectively avoid the difficulty of charge injection in the light-emitting layer caused by its wide bandgap, thereby reducing the driving voltage of the device. The device prepared by using the compound of the present invention as the host material of the light-emitting layer has made remarkable progress in comprehensive performance such as driving voltage, current efficiency, and lifespan. Detailed implementation manners

[0056] It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0057] Intermediate 1: Synthesis of 3-chloro-9-phenylphenanthro[2,3-d]oxazole

[0058]

[0059] S1. In a 500 mL reaction flask, add 6-bromo-2-phenylbenz[d]oxazole-5-carbaldehyde (26.59 g, 88 mmol), (4-chlorophenyl)boronic acid (12.51 g, 80 mmol), potassium carbonate (22.08 g, 160 mmol), 250 mL of a toluene / ethanol / water mixed solvent with a volume ratio of 2:1:1. Purge the air with nitrogen. Then, add tetrakis(triphenylphosphine)palladium (0.46 g, 0.4 mmol), heat to 85 °C, stir and react for about 8 h, then cool to room temperature, filter, separate the liquid of the filtrate, concentrate the organic phase, and purify it together with the filter cake with ethanol and / or tetrahydrofuran to obtain 17.35 g of intermediate a1 with a yield of 65%;

[0060] S2. In a 500 mL reaction flask, add methoxymethyltriphenylphosphonium chloride (20.57 g, 60 mmol), potassium tert-butoxide (6.73 g, 60 mmol), 200 mL of tetrahydrofuran, cool to 0 °C and stir and react for 0.5 h. Then add intermediate a1 (13.35 g, 40 mmol), stir and react at room temperature for 2 h, quench the reaction with water, extract with ethyl acetate, wash with water, dry over anhydrous sodium sulfate, filter, and concentrate. Then, 12.59 g of intermediate b1 can be obtained by column chromatography with a yield of 87%;

[0061] S3. In a 100 mL reaction flask, add intermediate b1 (7.24 g, 20 mmol), nickel chloride (0.13 g, 1 mmol), and 60 mL of 1,2-dichloroethane. Stir the reaction at room temperature for 2 hours, filter, concentrate the filtrate, and then separate by column chromatography to obtain 5.47 g of intermediate 1 with a yield of 83%.

[0062] Mass spectrometer MALDI-TOF-MS (m / z) = 329.7864, theoretical molecular weight: 329.7830, elemental analysis: theoretical values: C 21 H 12 N (%) : C 76.48; H 3.67; N 4.25; measured values: C 76.50; H 3.66; N 4.23.

[0063] Intermediate 2: Synthesis of 2-chloro-9-phenylphenanthro[3,2-d]thiazole

[0064]

[0065] S1. Replace 6-bromo-2-phenylbenzoxazole-5-carbaldehyde in step S1 of intermediate 1 with 5-bromo-2-phenylbenzothiazole-6-carbaldehyde (28.00 g, 88 mmol), and replace (4-chlorophenyl)boronic acid with (3-chlorophenyl)boronic acid (12.51 g, 80 mmol). Follow the other synthesis procedures according to step S1 of intermediate 1 to obtain 18.75 g of intermediate a2 with a yield of 67%;

[0066] S2. Replace intermediate a1 in step S2 of intermediate 1 with intermediate a2 (14.00 g, 40 mmol). Follow the other synthesis procedures according to step S2 of intermediate 1 to obtain 12.55 g of intermediate b2 with a yield of 83%;

[0067] S3. Replace intermediate b1 in step S3 of intermediate 1 with intermediate b2 (7.56 g, 20 mmol). Follow the other synthesis procedures according to step S3 of intermediate 1 to obtain 5.53 g of intermediate 2 with a yield of 80%.

[0068] Mass spectrometer MALDI-TOF-MS (m / z) = 345.8405, theoretical molecular weight: 345.8440, elemental analysis: theoretical values: C 21 H 12 N (%) : C 72.93; H 3.50; N 4.05; measured values: C 72.91; H 3.52; N 4.07.

[0069] Intermediate 3: Synthesis of 3-chloro-9,10-diphenyl-10H-phenanthro[2,3-d]imidazole

[0070]

[0071] S1. Replace 6-bromo-2-phenylbenzo[d]oxazole-5-carbaldehyde in step S1 of Intermediate 1 with 6-bromo-1,2-diphenyl-1H-benzo[d]imidazole-5-carbaldehyde (33.20 g, 88 mmol), and perform the other synthesis procedures according to step S1 of Intermediate 1 to obtain 20.28 g of Intermediate a3 with a yield of 62%;

[0072] S2. Replace Intermediate a1 in step S2 of Intermediate 1 with Intermediate a3 (16.36 g, 40 mmol), and perform the other synthesis procedures according to step S2 of Intermediate 1 to obtain 13.98 g of Intermediate b3 with a yield of 80%;

[0073] S3. Replace Intermediate b1 in step S3 of Intermediate 1 with Intermediate b3 (8.74 g, 20 mmol), and perform the other synthesis procedures according to step S3 of Intermediate 1 to obtain 6.88 g of Intermediate 3 with a yield of 85%.

[0074] Mass spectrometer MALDI-TOF-MS (m / z) = 404.8941, theoretical molecular weight: 404.8970, elemental analysis: theoretical values: C 27 H 17 N2 (%) : C 80.09; H 4.23; N 6.92; found values: C 80.10; H 4.21; N 6.93.

[0075] According to the synthesis methods of Intermediate 1, Intermediate 2, and Intermediate 3, using basically the same synthesis method (the same reaction molar ratio and reaction conditions), the following can be prepared:

[0076]

[0077] Synthesis Example 1: Synthesis of Compound (1-1)

[0078]

[0079] S1. In a 50 mL reaction flask, add 3-chloro-9-phenylphenanthro[2,3-d]oxazole (3.30 g, 10 mmol), (4-phenylnaphthalen-1-yl)boronic acid (2.48 g, 10 mmol), potassium carbonate (2.76 g, 20 mmol), 25 mL of a toluene / ethanol / water mixed solvent with a volume ratio of 2:1:1. Purge the air by introducing nitrogen. Then, add tetrakis(triphenylphosphine)palladium (0.06 g, 0.05 mmol). Heat to 85 °C and stir the reaction for about 8 h. Then cool to room temperature, filter, separate the layers of the filtrate, concentrate the organic phase, and elute the combined organic phase and the filter cake with a 10:1 mixture of petroleum ether and dichloromethane in a silica gel column. Concentrate to obtain 3.88 g of compound (1-1) with a yield of 78%.

[0080] Mass spectrometer MALDI-TOF-MS (m / z) = 497.6008, theoretical molecular weight: 497.5970, elemental analysis: theoretical values: C 37 H 23 N (%) : C 89.31; H 4.66; N 2.81; measured values: C 89.30; H 4.64; N 2.82.

[0081] Synthesis Example 2: Synthesis of compound (1-11)

[0082]

[0083] S1. Replace 3-chloro-9-phenylphenanthro[2,3-d]oxazole in step S1 of Synthesis Example 1 with 2-chloro-9-phenylphenanthro[3,2-d]thiazole (3.46 g, 10 mmol), and replace (4-phenylnaphthalen-1-yl)boronic acid with (4-(naphthalen-1-yl)phenylboronic acid (2.48 g, 10 mmol). Follow the other synthesis procedures according to step S1 of Synthesis Example 1 to obtain 3.75 g of compound (1-11) with a yield of 73%.

[0084] Mass spectrometer MALDI-TOF-MS (m / z) = 513.6529, theoretical molecular weight: 513.6580, elemental analysis: theoretical values: C 37 H 23 N (%) : C 86.52; H 4.51; N 2.73; measured values: C 86.52; H 4.53; N 2.72.

[0085] Synthesis Example 3: Synthesis of compound (1-18)

[0086]

[0087] S1. Replace 3-chloro-9-phenylphenanthro[2,3-d]oxazole in step S1 of Synthesis Example 1 with 2-chloro-8,9-diphenyl-8H-phenanthro[2,3-d]imidazole (4.05 g, 10 mmol), and replace (4-phenylnaphthalen-1-yl)boronic acid with (10-phenylanthracen-9-yl)boronic acid (2.98 g, 10 mmol). Perform the other synthesis procedures according to step S1 of Synthesis Example 1 to obtain 4.36 g of compound (1-18) with a yield of 70%.

[0088] Mass spectrometer MALDI-TOF-MS (m / z) = 622.7754, theoretical molecular weight: 622.7710, elemental analysis: theoretical values: C 47 H 30 N2 (%) : C 90.65; H 4.86; N 4.50; measured values: C 90.67; H 4.85; N 4.49.

[0089] Synthesis Example 4: Synthesis of compound (1-22)

[0090]

[0091] S1. Replace 3-chloro-9-phenylphenanthro[2,3-d]oxazole in step S1 of Synthesis Example 1 with 2-chloro-9-phenylphenanthro[3,2-d]oxazole (3.3 g, 10 mmol), and replace (4-phenylnaphthalen-1-yl)boronic acid with (8-phenyldibenz[b,d]furan-2-yl)boronic acid (2.88 g, 10 mmol). Perform the other synthesis procedures according to step S1 of Synthesis Example 1 to obtain 3.98 g of compound (1-22) with a yield of 74%.

[0092] Mass spectrometer MALDI-TOF-MS (m / z) = 537.6180, theoretical molecular weight: 537.6221, elemental analysis: theoretical values: C 39 H 23 N (%) : C 87.13; H 4.31; N 2.61; measured values: C 87.12; H 4.32; N 2.62.

[0093] Synthesis Example 5: Synthesis of compound (1-26)

[0094]

[0095] S1. Replace 3-chloro-9-phenylphenanthro[2,3-d]oxazole in step S1 of Synthesis Example 1 with 2-chloro-9-phenylphenanthro[3,2-d]oxazole (3.5 g, 10 mmol), and replace (4-phenylnaphthalen-1-yl)boronic acid with (9-phenyl-9H-carbazol-3-yl)boronic acid (2.87 g, 10 mmol). Follow the other synthesis procedures in step S1 of Synthesis Example 1 to obtain 4.20 g of compound (1-26) with a yield of 76%.

[0096] Mass spectrometer MALDI-TOF-MS (m / z) = 552.6995, theoretical molecular weight: 552.6950, elemental analysis: theoretical values: C 39 H 24 N2 (%) : C 84.75; H 4.38; N 5.07; measured values: C 84.77; H 4.38; N 5.05.

[0097] Synthesis Example 6: Synthesis of compound (1-33)

[0098]

[0099] S1. In a 50 mL reaction flask, add 3-chloro-9,10-phenyl-10H-phenanthro[2,3-d]imidazole (4.05 g, 10 mmol), 9H-carbazole (2.00 g, 12 mmol), potassium carbonate (2.76 g, 20 mmol) and 30 mL of N,N-dimethylacetamide. Pass in nitrogen, add 0.19 g (1 mmol) of copper(I) iodide and 0.36 g (2 mmol) of 1,10-phenanthroline, heat under reflux with stirring for 8 h, cool the temperature to room temperature, add water, separate the layers, distill the organic phase under reduced pressure, and purify with ethanol to obtain 4.40 g of compound (1-33) with a yield of 82%.

[0100] Mass spectrometer MALDI-TOF-MS (m / z) = 535.6538, theoretical molecular weight: 535.6500, elemental analysis: theoretical values: C 39 H 25 N3 (%) : C 87.45; H 4.70; N 7.84; measured values: C 87.44; H 4.68; N 7.85.

[0101] Synthesis Example 7: Synthesis of compound (1-48)

[0102]

[0103] S1. Replace 3-chloro-9,10-phenyl-10H-phenanthro[2,3-d]imidazole in step S1 of Synthesis Example 6 with 2-chloro-8,9-diphenyl-8H-phenanthro[2,3-d]imidazole (4.05 g, 10 mmol), and replace 9H-carbazole with diphenylamine (2.03 g, 12 mmol). For the other synthesis processes, follow step S1 of Synthesis Example 6 to obtain 4.63 g of compound (1-48) with a yield of 86%.

[0104] Mass spectrometer MALDI-TOF-MS (m / z) = 537.6609, theoretical molecular weight: 537.6660, elemental analysis: theoretical values: C 39 H 27 N3 (%) : C 87.12; H 5.06; N 7.82; measured values: C 87.14; H 5.07; N 7.81.

[0105] Synthesis Example 8: Synthesis of compound (2-1)

[0106]

[0107] S1. Replace (4-phenylnaphthalen-1-yl)boronic acid in step S1 of Synthesis Example 1 with (4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)boronic acid (3.53 g, 10 mmol). For the other synthesis processes, follow step S1 of Synthesis Example 1 to obtain 4.28 g of compound (2-1) with a yield of 71%.

[0108] Mass spectrometer MALDI-TOF-MS (m / z) = 602.6951, theoretical molecular weight: 602.6970, elemental analysis: theoretical values: C 42 H 26 N4 (%) : C 83.70; H 4.35; N 9.30; measured values: C 83.69; H 4.36; N 9.32.

[0109] Synthesis Example 9: Synthesis of compound (2-15)

[0110]

[0111] S1. Replace 3-chloro-9-phenylphenanthro[2,3-d]oxazole in step S1 of Synthesis Example 1 with 2-chloro-9,10-diphenyl-10H-phenanthro[2,3-d]imidazole (4.05 g, 10 mmol), and replace (4-phenylnaphthalen-1-yl)boronic acid with furano[2,3-b:5,4-b']dipyridin-3-ylboronic acid (2.14 g, 10 mmol). For the other synthesis processes, follow step S1 of Synthesis Example 1 to obtain 3.93 g of compound (2-15) with a yield of 73%.

[0112] The mass spectrometer MALDI-TOF-MS (m / z) = 538.6128, theoretical molecular weight: 538.6100, elemental analysis: theoretical values: C 37 H 22 N4 (%) : C 82.51; H 4.12; N 10.40; measured values: C 82.53; H 4.10; N 10.40.

[0113] Synthesis Example 10: Synthesis of compound (2-23)

[0114]

[0115] S1. Replace 3-chloro-9,10-phenyl-10H-phenanthro[2,3-d]imidazole in step S1 of Synthesis Example 6 with 3-chloro-9-phenylphenanthro[2,3-d]thiazole (3.46 g, 10 mmol), and replace 9H-carbazole with 9H-pyrido[3,4-b]indole (2.02 g, 12 mmol). Follow the other synthesis procedures in step S1 of Synthesis Example 6 to obtain 4.02 g of compound (2-23) with a yield of 84%.

[0116] The mass spectrometer MALDI-TOF-MS (m / z) = 477.5817, theoretical molecular weight: 477.5850, elemental analysis: theoretical values: C 32 H 19 N3 (%) : C 80.48; H 4.01; N 8.80; measured values: C 80.47; H 4.03; N 8.78.

[0117] Synthesis Example 11: Synthesis of compound (2-31)

[0118]

[0119] S1. Replace 3-chloro-9-phenylphenanthro[2,3-d]oxazole in step S1 of Synthesis Example 1 with 2-chloro-9-phenylphenanthro[3,2-d]oxazole (3.3 g, 10 mmol), and replace (4-phenylnaphthalen-1-yl)boronic acid with (4-(diphenylphosphino)phenyl)boronic acid (3.06 g, 10 mmol). Follow the other synthesis procedures in step S1 of Synthesis Example 1 to obtain 4.17 g of compound (2-31) with a yield of 75%.

[0120] The mass spectrometer MALDI-TOF-MS (m / z) = 555.6124, theoretical molecular weight: 555.6168, elemental analysis: theoretical values: C 39 H 26 N (%) : C 84.31; H 4.72; N 2.52; measured values: C 84.33; H 4.71; N 2.50.

[0121] Synthesis Example 12: Synthesis of Compound (2-35)

[0122]

[0123] S1. Replace 3-chloro-9,10-phenyl-10H-phenanthro[2,3-d]imidazole in Step S1 of Synthesis Example 6 with 3-chloro-9-phenylphenanthro[3,2-d]thiazole (3.46 g, 10 mmol), and replace 9H-carbazole with diphenylphosphine oxide (2.43 g, 12 mmol). For the other synthesis processes, follow Step S1 of Synthesis Example 6 to obtain 4.10 g of Compound (2-35) with a yield of 80%.

[0124] Mass spectrometer MALDI-TOF-MS (m / z) = 511.5806, theoretical molecular weight: 511.5788, elemental analysis: theoretical values: C 33 H 22 N (%) : C 77.48; H 4.33; N 2.74; measured values: C 77.49; H 4.31; N 2.76.

[0125] Device Example 1

[0126] The glass substrate with a 120-nm ITO transparent thin film was ultrasonically cleaned with acetone, isopropyl alcohol, and deionized water for 10 min each, dried in vacuum at 105°C for 2 h, and then subjected to UV ozone washing for 15 min. Then, the ITO glass substrate was transferred to a vacuum evaporation machine.

[0127] On the surface with the ITO thin film formed, molybdenum trioxide (MoO3) was vacuum-evaporated to form a 10-nm-thick hole injection layer;

[0128] Next, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC) was vacuum-evaporated on the above hole injection layer to form a 70-nm-thick hole transport layer;

[0129] Next, on the above hole transport layer, the Compound 1-1 prepared in the above Synthesis Example 1 (as the light-emitting host material, 95 wt%) and iridium(III) bis(1-phenylisoquinoline)(acetylacetonate) (Ir(piq)2(acac)) (as the light-emitting guest material, 5 wt%) were co-vacuum-evaporated to form a 30-nm-thick light-emitting layer;

[0130] Next, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine (TmPyPB) was vacuum-evaporated on the above light-emitting layer to form a 40-nm-thick electron transport layer;

[0131] Next, on the above-mentioned electron transport layer, lithium fluoride (LiF) is vacuum-evaporated to form an electron injection layer with a thickness of 1 nm;

[0132] Finally, on the above-mentioned electron injection layer, aluminum (Al) is vacuum-evaporated to form a cathode with a thickness of 100 nm.

[0133] Device Examples 2 to Device Example 13

[0134] The organic electroluminescent device is prepared by the same method as in Device Example 1, except that the compounds synthesized in Synthesis Examples 2 to 12 and 4,4'-bis(9-carbazolyl)biphenyl (CBP) are used to replace the compound 1-1 prepared in Synthesis Example 1, respectively.

[0135] The organic electroluminescent devices prepared in the above device examples are subjected to performance tests, and the results are shown in Table 1:

[0136] Table 1

[0137]

[0138]

[0139] It can be seen from the data in Table 1 above that compared with the traditional 4,4'-bis(9-carbazolyl)biphenyl (CBP), the fused-ring compound provided by the present invention with a phenanthro-fused five-membered heterocyclic ring connected to a phenyl group as the core structure and bonded with hole-transporting or electron-transporting side groups has a higher triplet energy level due to the introduction of the phenanthro-fused five-membered heterocyclic ring and the fine regulation of the electron and hole balance of the compound by different types of electron donor-acceptor groups. As a result, the organic electroluminescent device prepared using the compound of the present invention as the light-emitting host material realizes pure red light emission, and the device has significant improvements in comprehensive performance such as driving voltage, current efficiency, and service life, effectively solving the problems of high driving voltage and low fluorescence quantum efficiency caused by difficult charge injection of the host material in current organic electroluminescent devices.

[0140] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fused-ring compound, characterized in that, The fused-ring compound has the structure shown in formula (I): Wherein, one of X and Y is N, and the other of X and Y is selected from O or S; The corresponding representation is a single bond, located on the left or right side of the central axis of the five-membered ring, forming one of the double bonds in the five-membered heterocycle; L0 is selected from a single bond, phenylene, biphenylene, naphthylene; R1 is phenyl; R0 is selected from one of the groups shown in the following A1, A2, A3, A4 or A5: The A1 is expressed as: The A2 is expressed as: The A3 is expressed as: The A4 is expressed as: The A5 is represented as: Wherein, Z1 is C, CH or N, the number of Z1 being N is 1 or 2, and two adjacent Z1 are not N at the same time. When Z1 is C, it is the substitution site where R0 bridges L0 or the substitution site of R 24 , R 25 ; Q3 and Q4 are each independently selected from O, S, N(R 32 ), C(R 33 )(R 34 ); R 14 、R 15 、R 18 、R 20 、R 24 、R 25 、R 28 、R 29 、R 30 、R 31 、R 32 、R 33 、R 34 are each independently selected from hydrogen, a fluoro group, a nitro group, a cyano group, an alkyl group having 1 to 6 carbon atoms, a phenyl group which is unsubstituted or substituted by a fluoro group, a nitro group, a cyano group, an alkyl group having 1 to 6 carbon atoms or a naphthyl group, a biphenyl group which is unsubstituted or substituted by a fluoro group, a nitro group, a cyano group, an alkyl group having 1 to 6 carbon atoms or a phenyl group, and a naphthyl group which is unsubstituted or substituted by a fluoro group, a nitro group, a cyano group, an alkyl group having 1 to 6 carbon atoms or a phenyl group.

2. The fused-ring compound according to claim 1, characterized in that: The said which is further expressed as The said is further expressed as: The said which is further expressed as The said which is further expressed as The said which is further expressed as The said which is further expressed as 3. A polycyclic compound according to claim 2, wherein: The fused-ring compound is selected from the following structural formulas:

4. An organic electroluminescent device mainly includes a cathode, an anode, and an organic layer between the two electrodes, characterized in that: The organic layer between the two electrodes contains the fused-ring compound according to any one of claims 1-3.

5. The organic electroluminescent device according to claim 4, characterized in that, The organic layer between the two electrodes includes a light-emitting layer, the light-emitting layer is composed of a light-emitting host and a light-emitting guest, and the light-emitting host contains the fused-ring compound according to any one of claims 1-3.

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