Carbazole compound, composition and organic electroluminescent device

Abstract

The invention provides a carbazole compound, a composition and an organic electroluminescent device. The carbazole compound has a structure as shown in a formula A, and hydrogen atoms in the compound as shown in the formula A can be independently replaced by deuterium atoms. The composition comprises a first component and a second component, wherein the first component is a compound as shown in a formula A; the organic electroluminescent device with excellent performance is prepared by taking the carbazole compound with a specific structure as a material of the luminescent layer of the organic electroluminescent device, so that the organic electroluminescent device has relatively low driving voltage, relatively high current efficiency and relatively long service life.

Description

Technical Field

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

[0002] Compared with other flat panel displays (for example, liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), etc.), organic electroluminescent devices (OLEDs) have a simpler structure, various processing advantages, higher brightness, excellent viewing angle characteristics, faster response speeds, and lower driving voltages. Therefore, they are also fully developed to be used as light sources for flat panel displays (for example, wall-mounted TVs, etc.), or as backlight units for displays, illuminators, billboards, etc.

[0003] The structure of an organic electroluminescent device specifically includes an anode, a cathode, and an organic layer therebetween. In order to improve the efficiency and stability of an organic electroluminescent element, the organic material layer includes multiple layers with different materials. In order to meet people's higher requirements for OLED devices, the field urgently needs to develop more types of materials to improve the performance of OLED devices in terms of current efficiency, life span, etc. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a carbazole compound, a composition and an organic electroluminescent device. In the present invention, by designing the specific composition of the composition and using the composition as the material of the light-emitting layer, the prepared organic electroluminescent device has a lower driving voltage, a higher current efficiency and a longer life.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a carbazole compound having a structure as shown in the following formula A:

[0007]

[0008] The hydrogen atoms in the compounds of formula A may each independently be replaced by a deuterium atom (D).

[0009] The invention uses a carbazole compound with a specific structure as a material for a light-emitting layer of an organic electroluminescent device to prepare an organic electroluminescent device with excellent performance, so that the organic electroluminescent device has a lower driving voltage, a higher current efficiency and a longer service life. In addition, the carbazole compound is used as a first component in combination with a specific second component, so that the prepared organic electroluminescent device has a lower driving voltage, a higher current efficiency and a longer service life.

[0010] In the present invention, "D" represents a deuterium atom, and the same shall apply hereinafter.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit 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.

[0012] As a preferred technical solution of the present invention, the compound of formula A is selected from any one of the following compounds:

[0013]

[0014]

[0015] Preferably, the compound of formula A is selected from any one of the following compounds:

[0016]

[0017] It should be noted that the present invention does not have any special limitation on the synthesis method of the compound of formula A, and any commonly used synthesis method in the art is applicable.

[0018] In a second aspect, the present invention provides a composition, comprising a first component and a second component, wherein the first component comprises a compound of formula A as described in the first aspect, and the second component comprises a compound having a structure as shown in the following formula B:

[0019]

[0020] The hydrogen atoms in the compounds of formula B may each independently be replaced by a deuterium atom (D).

[0021] As a preferred technical solution of the present invention, at least one hydrogen atom in the compound of formula A is replaced by a deuterium atom.

[0022] Preferably, the compound of formula A is selected from any one of the following compounds P1-P15:

[0023]

[0024]

[0025] As a preferred technical solution of the present invention, at least one hydrogen atom in the compound of formula B is replaced by a deuterium atom.

[0026] Preferably, the compound of formula B is compound C2-D:

[0027]

[0028] In a third aspect, the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode and an organic thin film layer disposed between the anode and the cathode;

[0029] The material of the organic thin film layer includes the compound of formula A described in the first aspect and / or the composition described in the second aspect.

[0030] Preferably, the organic thin film layer comprises a light-emitting layer, and the main material of the light-emitting layer comprises the compound of formula A as described in the first aspect or / and the composition as described in the second aspect.

[0031] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0032] As a preferred technical solution of the present invention, the organic electroluminescent device is a green organic electroluminescent device.

[0033] The luminescent layer in the present invention includes a luminescent layer main material and a doping material, wherein the doping material is also called a dye or a phosphorescent luminescent material. The luminescent layer main material can be a single compound or a mixture of two or more compounds.

[0034] 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 yellow phosphorescent light-emitting layer.

[0035] The volume percentage of the main material in the phosphorescent layer is 60% to 99.9% (for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98% or 99.9%, etc.), preferably 70% to 99.5%, and more preferably 85% to 95%.

[0036] In the present invention, the doping material of the light-emitting layer may be a phosphorescent material, which is also called a triplet light-emitting material, and refers to the light emitted from a triplet excited state. The specific selection of the phosphorescent material in the present invention is not particularly limited, and the doping materials of the light-emitting layer commonly used in the art are applicable, including but not limited to: a compound having a structure shown in Formula PD:

[0037]

[0038] Wherein, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0039] Y1-Y4 are each independently selected from carbon or nitrogen;

[0040] 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;

[0041] Cy1 and Cy2 are each independently selected from phenyl, naphthyl, fluorenyl, spirofluorenyl, indenyl, pyrrolyl, thienyl, furanyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinolyl, isoquinolyl, benzoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, benzimidazolyl, benzofuranyl, benzothienyl, isobenzothienyl, benzimidazolyl, benzoxazolyl, triazolyl, tetrazolyl, oxadiazolyl, triazine, dibenzofuranyl, dibenzothienyl, N-heterocarbazolyl, N-heterodibenzofuranyl, wherein Cy1 and Cy2 may be optionally linked to each other via a single bond or an organic linking group;

[0042] Any two ligands of M, or more than two ligands, may be connected by a single bond or a double bond, or may be bridged by O or S, or may be connected by any chemical group or chemical structure to form a structural form that conforms to chemical principles;

[0043] R 91 and R 92each independently selected from -H, -D, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, carboxylic acid, carboxylate, sulfonic acid, sulfonate, phosphoric acid, phosphate, -SF5, substituted or unsubstituted C1-C60 (e.g., C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkyl, substituted or unsubstituted C2-C6 C2-C60 (for example, C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkynyl, substituted or unsubstituted C1-C60 (for example, C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) C2-C10 (for example, C2, C3, C4, C5, C6, C7, C8, C9 or C10) heterocycloalkyl, substituted or unsubstituted C6-C60 (for example, C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60) aryl, substituted or unsubstituted C6-C60 (for example, C2, C3, C4, C5, C6, C7, C8, C9 or C10) For example, it can be any one of C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60) aryloxy, substituted or unsubstituted C6-C60 (for example, it can be C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60) arylthio, substituted or unsubstituted monovalent non-aromatic fused polycyclic group, and substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group.

[0044] a1 and a2 are each independently an integer selected from 1-5, for example, 1, 2, 3, 4 or 5;

[0045] b is an integer selected from 0-4, for example, 0, 1, 2, 3 or 4;

[0046] a is selected from 1, 2 or 3;

[0047] L1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0048] Preferably, the compound of formula PD is selected from any one of the following compounds:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] In a fourth aspect, the present invention provides a display device, comprising the organic electroluminescent device as described in the third aspect.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The invention uses carbazole compounds with a specific structure as the material of the light-emitting layer of the organic electroluminescent device to prepare an organic electroluminescent device with excellent performance, so that the organic electroluminescent device has a lower driving voltage, a higher current efficiency and a longer service life. DETAILED DESCRIPTION

[0058] 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.

[0059] Synthesis Example 1 Synthesis of Compound I

[0060] This synthesis example provides compound I and its synthesis method, and its synthesis method is as follows:

[0061]

[0062] Under a nitrogen atmosphere, dry toluene (80 mL), intermediate MI-1 (4.1 g), 3-bromo-N-phenylcarbazole (3.2 g), Pd(dba)2 (bis(dibenzylideneacetonepalladium, 0.1 g), 0.8 g of 10% tri-tert-butylphosphine toluene solution (the mass of tri-tert-butylphosphine is 0.08 g) and sodium tert-butoxide (1.2 g) were added to a three-necked flask, heated to reflux temperature, reacted for 6 h, cooled to room temperature, and divided by adding water. The organic layer was then washed with water until neutral, dried with magnesium sulfate, filtered to remove the magnesium sulfate, concentrated to dryness, and crystallized from toluene to obtain Compound I (5.6 g).

[0063] Mass spectrometry was performed on compound I: the mass-to-charge ratio (m / z) was measured to be 649.25.

[0064] Synthesis Example 2 Synthesis of Compound P1

[0065] This synthesis example provides compound P1 and its synthesis method, and its synthesis method is as follows:

[0066]

[0067] (1) Synthesis of intermediate P1-1

[0068] Referring to the synthesis method of compound I, intermediate P1-1 was prepared using corresponding raw materials.

[0069] The intermediate P1-1 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 427.28.

[0070] (2) Synthesis of Compound P1

[0071] Compound P1 was prepared by using the corresponding raw materials with reference to the synthesis method of compound I. Compound P1 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 668.37.

[0072] Synthesis Example 3 Synthesis of Compound P5

[0073] This synthesis example provides compound P5 and its synthesis method, and its synthesis method is as follows:

[0074]

[0075] Compound P5 was prepared by using the corresponding raw materials in accordance with the synthesis method of compound I. Compound P5 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 661.33.

[0076] Synthesis Example 4 Synthesis of Compound P7

[0077] This synthesis example provides compound P7 and its synthesis method, and its synthesis method is as follows:

[0078]

[0079] (1) Synthesis of intermediate P7-1

[0080] The intermediate P7-1 was prepared by using the corresponding raw materials with reference to the synthesis method of compound I. The intermediate P7-1 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 519.33.

[0081] (2) Synthesis of Compound P7

[0082] Compound P7 was prepared by using the corresponding raw materials in accordance with the synthesis method of compound I. Compound P7 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 671.39.

[0083] Other compounds not listed can be synthesized by referring to the above examples.

[0084] The specific structures of some compositions used in the following device embodiments and device comparative examples are as follows:

[0085]

[0086] Device Example 1

[0087] The device embodiment provides an organic electroluminescent device, and the compound or composition provided by the present invention is selected as the green light host material in the organic electroluminescent device.

[0088] The structure of the organic electroluminescent device is: ITO / HT-1 (40nm) / green light host material (35nm): PGD-1 [10%] / Alq3 (25nm) / LiF (0.5nm) / Al (150nm). "PGD-1 [10%]" refers to the doping ratio of the green light dye, that is, the volume ratio of the green light host material to PGD-1 is 90:10.

[0089] The preparation process of organic electroluminescent device is as follows:

[0090] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0091] Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -6 ~9×10 -5 Pa, vacuum evaporating a hole transport layer HT-1 on the above anode layer film, the evaporation rate is 0.1nm / s, and the evaporation film thickness is 40nm;

[0092] A green light host material and dye PGD-1 are vacuum-deposited on the hole transport layer as the light-emitting layer of the organic electroluminescent device, with a deposition rate of 0.1 nm / s and a total deposition thickness of 35 nm. In the present device embodiment, the green light host material is compound I;

[0093] The electron transport layer Alq3 is vacuum evaporated on the light-emitting layer, and the evaporation rate is 0.1nm / s, and the evaporation film thickness is 25nm;

[0094] 0.5 nm of LiF and 150 nm of Al were vacuum-deposited on the electron transport layer as the electron injection layer and cathode.

[0095] Device Examples 2-7

[0096] Device comparison examples 2-7 provide an organic electroluminescent device, which differs from device example 1 only in that the green light main body material is different (see Table 1 below for details). If the green light main body is two components, the green light main body includes a first component and a second component. The first component and the second component are placed in different evaporation sources for heating, and the heating rate is controlled so that the volume ratio of each component evaporated onto the substrate is 1:1, as the green light main body material.

[0097] The other preparation steps and conditions are the same as those in device embodiment 1.

[0098] Device Comparison Examples 1-6

[0099] Device Comparative Examples 1-6 respectively provide an organic electroluminescent device, which differs from Device Example 1 only in that the green light host material is different (see Table 1 below for details). If the green light host is two components, the green light host includes a first component and a second component. The first component and the second component are placed in different evaporation sources for heating, and the heating rate is controlled so that the volume ratio of each component evaporated onto the substrate is 1:1, as the green light host material. Other preparation steps and conditions are the same as those of Device Example 1.

[0100] Performance Test:

[0101] The brightness, driving voltage, current efficiency, and life test LT90 of the prepared organic electroluminescent device were measured. The life test LT90 refers to the current density at room temperature (25-27°C) at the initial brightness (here 1000cd / m 2 ), the time required for the brightness to decrease to 90% of the initial brightness. The test results are detailed in Table 1 below. The driving voltage, current efficiency, and LT90 life are relative values.

[0102] Table 1

[0103]

[0104]

[0105] From the comparison of the relevant data of device examples 1-3 and device comparative examples 1-2, it can be seen that the OLED device prepared by using the compound of formula A having a specific structure in the present invention has a lower driving voltage, a higher current efficiency and a longer lifespan.

[0106] From the comparison of the relevant data of device embodiments 4-7 and device comparison examples 3-6, it can be seen that the OLED device prepared in the present invention uses formula A with a specific structure as the first component of the green light main body, and formula B with a specific structure as the second component of the green light main body has a lower driving voltage, higher current efficiency and longer life.

[0107] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A carbazole compound, characterized in that The carbazole compound has a structure shown in the following formula A: The hydrogen atoms in the compounds of formula A may each independently be replaced by a deuterium atom.

2. The carbazole compound according to claim 1, characterized in that The compound of formula A is selected from any one of the following compounds:

3. The carbazole compound according to claim 1 or 2, characterized in that The compound of formula A is selected from any one of the following compounds:

4. A composition, characterized in that The composition comprises a first component and a second component, wherein the first component comprises a compound of formula A as described in any one of claims 1 to 3, and the second component comprises a compound having a structure shown in the following formula B: The hydrogen atoms in the compounds of formula B may each independently be replaced by a deuterium atom.

5. The composition according to claim 4, characterized in that At least one hydrogen atom in the compound of formula A is replaced by a deuterium atom; Preferably, the compound of formula A is selected from any one of the following compounds P1-P15:

6. The composition according to claim 4 or 5, characterized in that At least one hydrogen atom in the compound of formula B is replaced by a deuterium atom; Preferably, the compound of formula B is compound C2-D:

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode; The material of the organic thin film layer includes the compound of formula A as described in any one of claims 1 to 3 or / and the composition as described in any one of claims 4 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that: The organic thin film layer comprises a light-emitting layer, and a main material of the light-emitting layer comprises the compound of formula A as described in any one of claims 1 to 3 or / and the composition as described in any one of claims 4 to 6.

9. The organic electroluminescent device according to claim 7 or 8, characterized in that: The light-emitting layer is a phosphorescent light-emitting layer.

10. The organic electroluminescent device according to any one of claims 7 to 9, characterized in that: The organic electroluminescent device is a green organic electroluminescent device.

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