Indolocarbazole compound, intermediate and organic electroluminescent device

Abstract

The invention provides an indolocarbazole compound, an intermediate and an organic electroluminescent device. The structure of the indolocarbazole compound is designed, the indolocarbazole compound is used as a main body material of a light-emitting layer of the OLED device, and the prepared OLED device has relatively low driving voltage, relatively high current efficiency and relatively long service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescent materials, and particularly relates to an indolocarbazole compound, an intermediate and an organic electroluminescent device. Background Art

[0002] A display integrates electronic, communication and information processing technologies, and is regarded as another major development opportunity for the electronics industry after electronics and computers. Display technology and displays occupy a very important position in the development process of information technology. Displays on televisions, computers, telephones and various instruments and meters provide people with a large amount of information in daily life and work. In recent years, new display technologies have become the focus of research. Among them, flat panel displays have the advantages of small weight, low power consumption, easy portability, etc., and have become a research hotspot.

[0003] Among various current flat panel displays, liquid crystal displays (LCDs) play an important role. However, liquid crystal displays (LCDs) have many deficiencies: they do not emit light by themselves, rely on light sources or ambient light, have viewing angle problems, slow response speeds, low resolutions, etc. Therefore, people have been looking for new flat panel display technologies. The phenomenon of organic electroluminescence was discovered as early as 1963, but it did not attract people's attention at that time; until 1987, the research group of Tang from Eastman Kodak Company in the United States published a high-brightness, high-efficiency thin-film organic electroluminescent device (OLED) made of organic fluorescent materials and hole materials driven by a direct current low voltage, this technology has regained attention and created a brand-new research field.

[0004] OLEDs have outstanding advantages, such as low power consumption, fast response speed, easy bending, wide viewing angle, large-area display, full-color emission, etc., and can be compatible with various existing standards and technologies to make low-cost light-emitting devices, showing broad application prospects in realizing color flat panel displays. In the past few decades, OLEDs, as a new display technology, have achieved great development and have been widely used in the fields of flat panel display, flexible display, solid-state lighting and vehicle-mounted display.

[0005] Therefore, developing more types of OLED materials with more perfect properties to meet the usage requirements of high-performance OLED devices is the research focus in this field. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an indolocarbazole compound, an intermediate and an organic electroluminescent device. In the present invention, by designing the structure of the indolocarbazole compound, the indolocarbazole compound is used as the host material of the light-emitting layer of the OLED device, and the prepared OLED device has a lower driving voltage, a higher current efficiency and a longer lifespan.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides an indolocarbazole compound, which is obtained by fusing the group shown in Formula I-A with any two adjacent carbon atoms on the A ring in Formula I-B, where * represents the fusion site of the group shown in Formula I-A:

[0009]

[0010] Wherein, R1 and R2 are each independently selected from at least one of C6-C40 aryl or C6-C30 heteroaryl;

[0011] L is selected from any one of a single bond, C6-C20 arylene or C6-C30 heteroarylene; and when L is selected from a single bond and any one of R1 and R2 is selected from a phenyl group, the other is not selected from a biphenyl group;

[0012] X1, X2, and X3 are each independently selected from an N atom or CH, and at least one of X1, X2, and X3 is selected from an N atom;

[0013] The hydrogen atoms in the indolocarbazole compound can each independently be substituted by at least one of deuterium atoms (-D), -F, -CN, triphenylmethyl, triphenylsilyl, C1-C12 alkyl, or C1-C12 alkoxy.

[0014] In the present invention, by designing the structure of the indolocarbazole compound, the indolocarbazole compound is used as the host material of the light-emitting layer of the OLED device, and the prepared OLED device has a lower driving voltage, a higher current efficiency, and a longer lifespan.

[0015] In the present invention, C6-C40 can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.

[0016] C6-C30 can be C6, C8, C10, C12, C16, C20, C24, C28, or C30, etc.

[0017] C6-C20 can be C6, C8, C10, C12, C16, or C20, etc.

[0018] C1-C12 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, or C12.

[0019] It should be noted that in the present invention, "D" represents a deuterium atom, and where not separately marked in the present invention, H and hydrogen therein both represent "protium". The same applies hereinafter.

[0020] The following are the preferred technical solutions of the present invention, but do not constitute a limitation to the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0021] As a preferred technical solution of the present invention, the C6-C40 aryl group is selected from any one or a combination of at least two of phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthofluorenyl, pyrenyl, perylenyl, spirofluorene, triphenylene, fluoranthenyl, hydrobenzanthryl, indeno[1,2-b]fluorene, benzo[1,2,3-cd]indeno[1,2-b]fluorene, dibenzo[1,2,3-cd]indeno[1,2-b]fluorene, naphthofluorenyl, triphenylmethyl, triphenylsilyl or benzonaphthofluorenyl.

[0022] As a preferred technical solution of the present invention, the C6-C30 heteroaryl group is selected from any one or a combination of at least two of carbazolyl, dibenzothiophenyl, dibenzofuranyl, naphthobenzo[2,3-b]furanyl, naphthobenzo[2,3-b]thiophenyl, dinaphtho[2,3-b:2',3'-d]furanyl, dinaphtho[2,3-b:2',3'-d]thiophenyl.

[0023] As a preferred technical solution of the present invention, the C6-C20 arylene group is selected from any one of phenylene, naphthylene, biphenylene, anthrylene, phenanthrylene, fluorenylene, triphenylene or fluoranthenylene.

[0024] As a preferred technical solution of the present invention, the C6-C30 heteroarylene group is selected from any one or a combination of at least two of carbazolylene, dibenzothiophenylene, dibenzofuranylene, naphthobenzo[2,3-b]furanylene, naphthobenzo[2,3-b]thiophenylene, dinaphtho[2,3-b:2',3'-d]furanylene, dinaphtho[2,3-b:2',3'-d]thiophenylene.

[0025] As a preferred technical solution of the present invention, the C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, n-butyl, tert-butyl, cyclopentyl, cyclohexyl, octyl, adamantyl.

[0026] As a preferred technical solution of the present invention, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy.

[0027] As a preferred technical solution of the present invention, R1 and R2 are each independently selected from any one or a combination of at least two of phenyl, naphthyl, 9,9-dimethylfluorenyl, fluoranthenyl, triphenylene, anthryl, phenanthryl, biphenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl.

[0028] Preferably, R1 and R2 are each independently selected from any one or a combination of at least two of phenyl, naphthyl, fluoranthenyl, triphenylene, dibenzofuranyl, dibenzothiophenyl, carbazolyl.

[0029] As a preferred technical solution of the present invention, L is selected from any one or a combination of at least two of a single bond, a phenylene group, a naphthylene group, a biphenylene group, a 9,9-dimethylfluorenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, and a carbazolyl group.

[0030] Preferably, L is selected from any one of a single bond, a phenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, and a carbazolyl group.

[0031] Preferably, L is selected from a single bond.

[0032] As a preferred technical solution of the present invention, at least two of X1, X2, and X3 are selected from N atoms.

[0033] Preferably, X1, X2, and X3 are all selected from N atoms.

[0034] As a preferred technical solution of the present invention, the hydrogen atoms in the compound of formula I can each independently be substituted by at least one of a deuterium atom, -F, -CN, a methyl group, an ethyl group, a propyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, a trityl group, and a triphenylsilyl group. As a preferred technical solution of the present invention, the indolocarbazole compound has a structure shown in the following formula I or formula II:

[0035]

[0036] wherein, R1, R2, L, X1, X2, and X3 have the same definitions as above;

[0037] The hydrogen atoms in the compound of formula I and the compound of formula II can each independently be substituted by at least one of a deuterium atom, -F, -CN, a trityl group, a triphenylsilyl group, a C1-C12 alkyl group, and a C1-C12 alkoxy group.

[0038] As a preferred technical solution of the present invention, the indolocarbazole compound is selected from any one of the following substituted or unsubstituted compounds:

[0039]

[0040]

[0041]

[0042] The substitution means that the hydrogen atoms in the above indolocarbazole compound can each independently be replaced by a deuterium atom.

[0043] Preferably, the indolocarbazole compound includes the following compounds:

[0044]

[0045]

[0046] It should be noted that the present invention does not make any special limitations on the preparation method of indolocarbazole compounds, and the commonly used preparation methods in the art are applicable.

[0047] In a second aspect, the present invention provides an intermediate having the following structure;

[0048]

[0049] The intermediate is used for preparing the indolocarbazole compounds as described in the first aspect.

[0050] In a third aspect, the present invention provides an organic electroluminescent device, which includes an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode;

[0051] The material of the organic thin film layer includes the indolocarbazole compounds as described in the first aspect.

[0052] Preferably, the organic thin film layer includes a light-emitting layer;

[0053] The host material of the light-emitting layer includes the indolocarbazole compounds as described in the first aspect.

[0054] As a preferred technical solution of the present invention, the organic electroluminescent device is a green organic electroluminescent device.

[0055] In the present invention, the light-emitting layer includes a light-emitting layer host material and a doping material, where the doping material is also called a dye or a phosphorescent material. The light-emitting layer host material can be a single compound or a mixture formed by two or more compounds.

[0056] Preferably, the light-emitting layer includes a phosphorescent light-emitting layer, and the phosphorescent light-emitting layer includes a green phosphorescent light-emitting layer, a red phosphorescent light-emitting layer, and a blue phosphorescent light-emitting layer.

[0057] The volume percentage content of the host material in the phosphorescent light-emitting layer is 60% - 99.9% (for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98% or 99.9%, etc.), preferably 70% - 99.5%, and further preferably 85% - 95%.

[0058] In the present invention, the doping material of the light-emitting layer can be a phosphorescent material, which is also called a triplet light-emitting material and refers to the light emitted by a substance from the triplet excited state. In the present invention, no special limitation is made on the specific selection of the phosphorescent material, and the doping materials of the light-emitting layer commonly used in the art are all applicable. Exemplarily, it includes but is not limited to: a compound having a structure represented by formula PD:

[0059]

[0060] wherein M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0061] Y1 - Y4 are each independently selected from carbon or nitrogen;

[0062] Y1 and Y2 can be connected by a single bond or a double bond, and Y3 and Y4 can be connected by a single bond or a double bond;

[0063] Cy1 and Cy2 are each independently selected from phenyl, naphthyl, fluorenyl, spirofluorenyl, indenyl, pyrrolyl, thienyl, furyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinolinyl, isoquinolinyl, benzoquinolinyl, quinoxalinyl, quinazolinyl, carbazolyl, benzimidazolyl, benzofuryl, benzothienyl, isobenzothienyl, benzimidazazolyl, benzazolyl, triazolyl, tetrazolyl, dioxazolyl, triazinyl, dibenzofuryl, dibenzothienyl, N-heterocarbazolyl, N-heterodibenzofuryl, and Cy1 and Cy2 can optionally be connected to each other via a single bond or an organic linking group;

[0064] Between any two ligands of M, between two or more ligands, they can be connected by a single bond or a double bond, or can be bridged by O or S, or can be connected by any chemical group or chemical structure to form a structural form conforming to chemical principles;

[0065] R 91 and R 92Each independently selected from -H, -D, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazino, hydrazono, carboxylic acid group, carboxylate group, sulfonic acid group, sulfonate group, phosphoric acid group, phosphate group, -SF5, substituted or unsubstituted C1-C60 (such as C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkyl, substituted or unsubstituted C2-C60 (such as C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkenyl, substituted or unsubstituted C2-C60 (such as C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkynyl, substituted or unsubstituted C1-C60 (such as C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkoxy, substituted or unsubstituted C2-C10 (such as C2, C3, C4, C5, C6, C7, C8, C9 or C10) heterocycloalkyl, substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) aryl, substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) aryloxy, substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) arylthio, substituted or unsubstituted monovalent non-aromatic fused polycyclic group, substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group.

[0066] a1 and a2 are each independently an integer selected from 1-5, such as 1, 2, 3, 4 or 5;

[0067] b is an integer selected from 0-4, such as 0, 1, 2, 3 or 4;

[0068] a is selected from 1, 2 or 3;

[0069] L1 is a monovalent organic ligand, divalent organic ligand or trivalent organic ligand.

[0070] Preferably, the PD compound of the formula is selected from any one of the following compounds:

[0071]

[0072]

[0073]

[0074]

[0075] In a fourth aspect, the present invention provides a display device, comprising the organic electroluminescent device as described in the third aspect.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] In the present invention, the structure of the indolecarbazole compound is designed so that the indolecarbazole compound is used as the main material of the light-emitting layer of the OLED device, and the prepared OLED device has a lower driving voltage, a higher current efficiency and a longer lifespan. DETAILED DESCRIPTION

[0078] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0079] Preparation Example 1 Synthesis of Intermediate P1-1

[0080] This preparation example provides an intermediate P1-1 and a synthesis method thereof, and the synthesis method thereof is as follows:

[0081]

[0082] Under nitrogen protection, dry toluene (80 mL), 5,8-dihydroindole [2,3-c] carbazole (2.7 g), 3'-bromo-1,1':2',1"-terphenyl (3.0 g), Pd(dba)2 (bis(dibenzylideneacetonepalladium, 0.0575 g), 10% tri-tert-butylphosphine toluene solution (the mass of tri-tert-butylphosphine solution is 0.4 g, and the amount of tri-tert-butylphosphine is 0.0002 mol) and sodium tert-butoxide (1.44 g) were added to a three-necked flask, heated to reflux, reacted for 8 hours, cooled to room temperature, and separated by adding water. The organic layer was then washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with a solvent of petroleum ether: ethyl acetate = 20:1 (volume ratio) to obtain intermediate P1-1 (2.1 g).

[0083] The intermediate P1-1 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 484.19.

[0084] Preparation Example 2 Synthesis of Intermediate P14-1

[0085] This preparation example provides an intermediate P14-1 and a synthesis method thereof, and the synthesis method thereof is as follows:

[0086]

[0087] Referring to the synthesis method of intermediate P1-1, intermediate P14-1 was prepared.

[0088] The intermediate P14-1 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 484.19.

[0089] Synthesis Example 1

[0090] This synthesis example provides compound P1 and its synthesis method, and its synthesis method is as follows:

[0091]

[0092] Under nitrogen protection, dry toluene (120 mL), intermediate P1-1 (5.0 g), 2-chloro-4,6-di(2-naphthyl)-1,3,5-triazine (3.6 g), Pd(dba)2 (bis(dibenzylideneacetonepalladium, 0.0575 g), 10% tri-tert-butylphosphine toluene solution (the mass of tri-tert-butylphosphine solution is 0.4 g, and the amount of tri-tert-butylphosphine is 0.0002 mol) and sodium tert-butoxide (1.44 g) were added to a three-necked flask, heated to 40°C for reaction for 2 h, then heated to 60°C for reaction for 2 h, then refluxed for 2 h, cooled to room temperature, water was added to separate, and then the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and crystallized twice with a mixed solvent of chloroform and toluene to obtain compound P1 (5.0 g).

[0093] The mass spectrometry detection of compound P1 was performed: the mass-to-charge ratio (m / z) was measured to be 815.30.

[0094] Synthesis Example 2-9

[0095] The synthesis examples are respectively a compound and a synthesis method thereof. The corresponding compound refers to the synthesis method of compound P1, and raw material 1 and raw material 2 are reacted to prepare the following compounds (see Table 1 below for details). The mass spectra of the prepared compounds are measured and the (m / z) values ​​are recorded. See Table 1 below for details.

[0096] Table 1

[0097]

[0098]

[0099] The synthesis of other compounds not listed can be carried out by referring to the above embodiments in combination with common knowledge in the art.

[0100] The specific structures of the partial compounds used in the following device examples and device comparative examples are as follows:

[0101]

[0102]

[0103] Device Example 1

[0104] This device example provides an organic electroluminescent device, and the compound provided by the present invention is selected as the green light host material in the organic electroluminescent device.

[0105] The structure of the organic electroluminescent device is: ITO / HT-1(40nm) / green light host material(35nm): PGD-1[10%] / ETL-1(25nm) / LiF(0.5nm) / Al(150nm).

[0106] The preparation process of the organic electroluminescent device is as follows:

[0107] The preparation method of the green light organic electroluminescent device is as follows:

[0108] Place the materials in a vacuum chamber, evacuate to 1×10 -5 ~1×10 -6 Pa, and vacuum deposit them onto the cleaned ITO substrate in sequence to prepare the OLED device.

[0109] Where PGD-1[10%] refers to the doping ratio of the dye, that is, the volume ratio of the host material to the dye PGD-1 is 90:10; HT-1 is a hole transport material, and ETL-1 is an electron transport material.

[0110] The green light host material of the green light organic electroluminescent device provided in this application example is compound P4.

[0111] Device Examples 2-5, Device Comparative Examples 1-2

[0112] Device Examples 2-5 and Device Comparative Examples 1-2 respectively provide an organic electroluminescent device, which is only different from Device Example 1 in that the green light host materials are different (see Table 2 below), and other preparation steps and conditions are the same as those in Device Example 1.

[0113] Performance test:

[0114] The brightness, driving voltage, current efficiency of the prepared organic electroluminescent device were measured, as well as the lifetime test LT90. Among them, the lifetime test LT90 refers to maintaining the current density at the initial brightness unchanged at room temperature (25~27℃) (here it is 1000cd / m 2The current density at [specific time], and the time required for the luminance to decrease to 90% of the initial luminance. The driving voltage, current efficiency, and LT90 lifetime are all relative values. The test results are shown in Table 2 below.

[0115] Table 2

[0116]

[0117]

[0118] As can be seen from the above, in the present invention, by designing the structure of indolo[3,2-b]carbazole compounds, these indolo[3,2-b]carbazole compounds are used as the host materials for the light-emitting layer of OLED devices, and the prepared OLED devices have a lower driving voltage, a higher current efficiency, and a longer lifetime.

[0119] Device Examples 6 - 8, Device Comparative Example 3

[0120] Device Examples 6 - 8 and Device Comparative Example 3 respectively provide an organic electroluminescent device. The difference from Device Example 1 is only that the green host materials are different (see Table 3 below), and the other preparation steps and conditions are the same as those in Device Example 1.

[0121] Performance Test:

[0122] The luminance, driving voltage, current efficiency of the prepared organic electroluminescent device were measured, and the lifetime test LT90 was also carried out. Among them, the lifetime test LT90 refers to the time required for the luminance to decrease to 90% of the initial luminance at room temperature (25 - 27 °C) while keeping the current density at the initial luminance unchanged (here it is 1000 cd / m 2 The current density at [specific time]). The driving voltage, current efficiency, and LT90 lifetime are all relative values. The test results are shown in Table 3 below.

[0123] Table 3

[0124] Green light host material <![CDATA[Required brightness / (cd / m 2 )]]> Driving voltage Current efficiency LT90 life Device Example 6 P11 1000 1.01 1.08 1.12 Device Example 7 P12 1000 0.93 1.02 1.08 Device Example 8 P13 1000 0.82 1.19 1.06 Device Comparative Example 3 D6 1000 1 1 1

[0125] As can be seen from the above, in the present invention, by designing the structure of indolo[3,2-b]carbazole compounds, these indolo[3,2-b]carbazole compounds are used as the host materials for the light-emitting layer of OLED devices, and the prepared OLED devices have a lower driving voltage, a higher current efficiency, and a longer lifetime.

[0126] Device Examples 9 - 10, Device Comparative Examples 4 - 6

[0127] Device Examples 9 - 10 and Device Comparative Examples 4 - 6 respectively provide an organic electroluminescent device. The difference from Device Example 1 is only that the green host materials are different (see Table 4 below), and the other preparation steps and conditions are the same as those in Device Example 1.

[0128] Performance test:

[0129] The test measured the brightness, driving voltage, current efficiency of the fabricated organic electroluminescent device, and the LT90 of the lifetime test. Among them, the LT90 of the lifetime test refers to the time required for the brightness to decrease to 90% of the initial brightness at room temperature (25 - 27 °C) while keeping the current density at the initial brightness unchanged (here it is the current density at 1000 cd / m 2 ). The driving voltage, current efficiency, and LT90 lifetime are all relative values. The test results are shown in Table 4 below.

[0130] Table 4

[0131] Green light host material <![CDATA[Required brightness / (cd / m 2 )]]> Driving voltage Current efficiency LT90 life Device Example 9 P14 1000 0.91 1.06 1.16 Device Example 10 P15 1000 0.94 1.01 1.47 Device Comparative Example 4 D3 1000 1 1 1 Device Comparative Example 5 D4 1000 1.02 0.98 0.81 Device Comparative Example 6 D5 1000 1.02 0.90 0.95

[0132] Device Examples 11 - 14, Device Comparative Example 7

[0133] Device Examples 11 - 14, Device Comparative Example 7 respectively provide an organic electroluminescent device, which is different from Device Example 1 only in that the green host material is different (see Table 5 below), and other preparation steps and conditions are the same as those of Device Example 1.

[0134] Performance test:

[0135] The test measured the brightness and driving voltage of the fabricated organic electroluminescent device. The voltage of the device at 1000 cd / m 2 was recorded, and the test results are shown in Table 5 below.

[0136] Table 5

[0137] Green light host material <![CDATA[Required luminance / (cd / m 2 )]]> Driving voltage (V) Device Example 11 P2 1000 6.22 Device Example 12 P3 1000 6.01 Device Example 13 P8 1000 5.56 Device Example 14 P9 1000 5.62 Device Comparative Example 7 D1 1000 6.28

[0138] Device Examples 14 - 18, Device Comparative Examples 6 - 7

[0139] Device Examples 14 - 18, Device Comparative Examples 6 - 7 respectively provide an organic electroluminescent device, which is different from Device Example 1 only in that the green host material is different, and PGD - 1 is replaced with an equal proportion of PGD - 2 (see Table 6 below), and other preparation steps and conditions are the same as those of Device Example 1.

[0140] Performance test:

[0141] The test measured the brightness, driving voltage, current efficiency of the fabricated organic electroluminescent device, and the LT90 of the lifetime test. Among them, the LT90 of the lifetime test refers to the time required for the brightness to decrease to 90% of the initial brightness at room temperature (25 - 27 °C) while keeping the current density at the initial brightness unchanged (here it is the current density at 1000 cd / m 2(current density at that time), the time required for the brightness to decrease to 90% of the initial brightness. The driving voltage, current efficiency, and LT90 life are all relative values. See Table 6 below for the test results.

[0142] Table 6

[0143]

[0144]

[0145] As can be seen from the above, in the present invention, by designing the structure of indolocarbazole compounds, the indolocarbazole compounds are used as the host material of the light-emitting layer of the OLED device, and the prepared OLED device has a lower driving voltage, a higher current efficiency, and a longer life.

[0146] The applicant declares that the present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An indolocarbazole compound, characterized in that, The indolocarbazole compound is obtained by fusing the group shown in Formula I-A with any two adjacent carbon atoms on the A ring in Formula I-B, where * represents the fusion site of the group shown in Formula I-A: Among them, R1 and R2 each independently selected from at least one of C6-C40 aryl or C6-C30 heteroaryl; L is selected from any one of a single bond, C6-C20 arylene or C6-C30 heteroarylene; and when L is selected from a single bond and any one of R1 and R2 is selected from a phenyl group, the other is not selected from a biphenyl group; X1, X2, and X3 each independently selected from an N atom or CH, and at least one of X1, X2, and X3 is selected from an N atom; The hydrogen atoms in the indolocarbazole compound can each independently be substituted by at least one of a deuterium atom, -F, -CN, a triphenylmethyl group, a triphenylsilyl group, a C1-C12 alkyl group, or a C1-C12 alkoxy group.

2. The indolocarbazole compound according to claim 1, characterized in that, The C6-C40 aryl is selected from any one or a combination of at least two of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthofluorenyl, pyrenyl, perylenyl, spirofluorene, triphenylene, fluoranthenyl, hydrobenzanthryl, indeno[1,2-b]fluorene, benzo[ghi]fluorene, dibenzo[ghi]fluorene, naphtho[2,1-a]fluorene, triphenylmethyl, triphenylsilyl, or benzonaphtho[2,1-a]fluorene; Preferably, the C6-C30 heteroaryl is selected from any one or a combination of at least two of carbazolyl, dibenzothiophenyl, dibenzofuranyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, dinaphthothiophenyl; Preferably, the C6-C20 arylene is selected from any one of phenylene, naphthylene, biphenylene, anthrylene, phenanthrylene, fluorenylene, triphenylene, or fluoranthenyl; Preferably, the C6-C30 heteroarylene is selected from any one or a combination of at least two of carbazolylene, dibenzothiophenylene, dibenzofuranylene, naphthobenzofuranylene, naphthobenzothiophenylene, dinaphthofuranylene, dinaphthothiophenylene; Preferably, the C1-C12 alkyl is selected from any one of methyl, ethyl, propyl, n-butyl, tert-butyl, cyclopentyl, cyclohexyl, octyl, adamantyl; Preferably, the C1-C12 alkoxy is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy.

3. The indolocarbazole compound according to claim 1 or 2, characterized in that R1 and R2 each independently selected from any one or a combination of at least two of phenyl, naphthyl, 9,9-dimethylfluorenyl, fluoranthenyl, triphenylene, anthracenyl, phenanthryl, biphenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl; Preferably, R1 and R2 each independently selected from any one or a combination of at least two of phenyl, naphthyl, fluoranthenyl, triphenylene, dibenzofuranyl, dibenzothiophenyl, carbazolyl.

4. The indolocarbazole compound according to any one of claims 1-3, characterized in that, L is selected from any one or a combination of at least two of a single bond, phenylene, naphthylene, biphenylene, 9,9-dimethylfluorenylene, dibenzofuranylene, dibenzothiophenylene, carbazolylene; Preferably, L is selected from any one of a single bond, a phenylene group, a dibenzofuranyl group, a dibenzothiophenyl group, and a carbazolyl group; Preferably, L is a single bond.

5. The indolocarbazole compound according to any one of claims 1-4, characterized in that, At least two of X1, X2, and X3 are N atoms; Preferably, X1, X2, and X3 are all N atoms; Preferably, each hydrogen atom in the compound of formula I can be independently substituted by at least one of a deuterium atom, -F, -CN, a methyl group, an ethyl group, a propyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, a trityl group, and a triphenylsilyl group.

6. The indolocarbazole compound according to any one of claims 1-5, characterized in that, The indolocarbazole compound has a structure represented by the following formula I or formula II: wherein R1, R2, L, X1, X2, and X3 have the same definitions as in claim 1; Each hydrogen atom in the compound of formula I and the compound of formula II can be independently substituted by at least one of a deuterium atom, -F, -CN, a trityl group, a triphenylsilyl group, a C1-C12 alkyl group, and a C1-C12 alkoxy group.

7. The indolocarbazole compound according to any one of claims 1-6, characterized in that, The indolocarbazole compound is selected from any one of the following substituted or unsubstituted compounds: The substitution means that each hydrogen atom in the above indolocarbazole compound can be independently substituted by a deuterium atom.

8. An intermediate, characterized in that, The intermediate has the following structure: The intermediate is used for preparing the indolocarbazole compound according to any one of claims 1-7.

9. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode; The material of the organic thin film layer includes the indolocarbazole compound according to any one of claims 1-7; Preferably, the organic thin film layer includes a light-emitting layer; The host material of the light-emitting layer includes the indolocarbazole compound according to any one of claims 1-7.

10. The organic electroluminescent device according to claim 9, wherein The organic electroluminescent device is a green organic electroluminescent device.

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