阅读说明：本技术 一种基于双极性有机电致发光材料及其制备方法 (Bipolar organic electroluminescent material and preparation method thereof ) 是由 万志豪 于 2020-06-15 设计创作，主要内容包括：本发明属光电显示器件技术领域,具体涉及一种双极性有机电致发光材料及其制备方法。本发明提供了一种双极性有机电致发光材料,其结构如式(I)所示。本发明还提供了一种双极性有机电致发光材料的制备方法,将式(II)所示化合物,3,10-二溴-14-(3-(5-苯基-1,3,4-恶二唑-2-基)苯基)-14H--双(S,S-二氧-二苯并噻吩)并吡咯和2-(3-(3,10-双(4,4,5,5-四甲基-1,3,2-二氧杂硼烷-2-基)-14H-双(S,S-二氧-二苯并噻吩)并吡咯-5-苯基-1,3,4-恶二唑通过Suzuki偶联反应制得式(I)所示聚合物。本发明解决了现有的有机电致发光材料难以兼顾空穴和电子传输效率,且电致发光效率较差的技术问题。(The invention belongs to the technical field of photoelectric display devices, and particularly relates to a bipolar organic electroluminescent material and a preparation method thereof. The invention provides a bipolar organic electroluminescent material, which has a structure shown in a formula (I). The invention also provides a preparation method of the bipolar organic electroluminescent material, which is characterized in that the polymer shown in the formula (I) is prepared by carrying out Suzuki coupling reaction on a compound shown in the formula (II), 3, 10-dibromo-14- (3- (5-phenyl-1, 3, 4-oxadiazole-2-yl) phenyl) -14H-bis (S, S-dioxo-dibenzothiophene) pyrrole and 2- (3- (3, 10-bis (4,4,5, 5-tetramethyl-1, 3, 2-dioxaborane-2-yl) -14H-bis (S, S-dioxo-dibenzothiophene) pyrrole-5-phenyl-1, 3, 4-oxadiazole, and poor electroluminescent efficiency.)

1. A bipolar organic electroluminescent material is characterized in that the structure is shown as formula (I):

wherein n is 1-500.

2. A preparation method of a bipolar organic electroluminescent material is characterized in that a compound shown as a formula (II), 3, 10-dibromo-14- (3- (5-phenyl-1, 3, 4-oxadiazole-2-yl) phenyl) -14H-bis (S, S-dioxo-dibenzothiophene) pyrrole and 2- (3- (3, 10-bis (4,4,5, 5-tetramethyl-1, 3, 2-dioxaborane-2-yl) -14H-bis (S, S-dioxo-dibenzothiophene) pyrrole-5-phenyl-1, 3, 4-oxadiazole are subjected to Suzuki coupling reaction to prepare a polymer shown as a formula (I),

3. the method for preparing a bipolar organic electroluminescent material as claimed in claim 2, wherein the time of the Suzuki coupling reaction is 24h to 36 h.

4. The method of claim 2, wherein the temperature of the Suzuki coupling reaction is 85 ℃.

Technical Field

The invention belongs to the technical field of photoelectric display devices, and particularly relates to a bipolar organic electroluminescent material and a preparation method thereof.

Background

The 21 st century is known as the new "electronic information age". With the development of the internet, smart phones, watches and tablet computers become an indispensable part of the life of people. The development of display technology is greatly promoted by the arrival of the information age, people pursue thinner, more energy-saving, larger and more flexible display, and organic electroluminescence is taken as the mainstream of the market. The organic electroluminescent diode has the advantages of low-voltage driving, self-luminescence, quick response, wide visual angle, thin thickness and the like, and a solid-state full-color display covering the whole visible spectrum can be selected through flexible substrate processing. The ink-jet printing or spin coating process is adopted, so that the production cost is greatly reduced, and great attention is paid to the technical field of display.

The electroluminescent material generally adopts unipolar micromolecules, and although the hole/electron transmission type micromolecule main material structure contains electron-donating groups or electron-withdrawing groups, the hole and electron transmission performance is good, a hole or electron blocking layer is usually required to be added into the device, the driving voltage is high, and the electroluminescent efficiency is poor.

Therefore, the conventional organic electroluminescent material is difficult to achieve both hole and electron transport efficiency, and the poor electroluminescent efficiency is a technical problem to be solved urgently by those skilled in the art.

Disclosure of Invention

The invention provides a bipolar organic electroluminescent material and a preparation method thereof, and solves the technical problems that the existing organic electroluminescent material is difficult to give consideration to both hole and electron transmission efficiency and the electroluminescent efficiency is poor.

The invention provides a bipolar organic electroluminescent material, which has a structure shown in a formula (I):

wherein n is 1-500.

The invention also provides a preparation method of the bipolar organic electroluminescent material, which is characterized in that a compound shown in the formula (II), 3, 10-dibromo-14- (3- (5-phenyl-1, 3, 4-oxadiazole-2-yl) phenyl) -14H-bis (S, S-dioxo-dibenzothiophene) pyrrole and 2- (3- (3, 10-bis (4,4,5, 5-tetramethyl-1, 3, 2-dioxaborane-2-yl) -14H-bis (S, S-dioxo-dibenzothiophene) pyrrole-5-phenyl-1, 3, 4-oxadiazole are subjected to Suzuki coupling reaction to prepare a polymer shown in the formula (I),

preferably, the time of the Suzuki coupling reaction is 24-36 h.

Preferably, the temperature of the Suzuki coupling reaction is 85 ℃.

The invention has the following beneficial effects:

after the spirofluorene unit is introduced into the polymer prepared by the method, the polymer HOMO energy level of the polymer is increased by about 0.48eV through the electron-donating group in the spirofluorene, and the polymer LUMO energy level is remarkably reduced through the electron-withdrawing property of the S ═ O unit in the polymer. The polymer has bipolar property, and the transmission and injection of electrons and holes are effectively promoted. The increase of the HOMO energy level of the polymer prepared in the embodiment of the present invention facilitates hole injection and transport, thereby resulting in a decrease of about 2V in driving voltage. The current efficiency can reach 1.36cd/A at most, and the maximum brightness can reach 2090cd/m²The color coordinates are all located near the standard blue light, and the difference is not large, which shows that the polymer prepared by the invention has higher color purity.

Drawings

FIG. 1 is a cyclic voltammogram of examples 12 to 13 of the present invention;

FIG. 2 is an EL spectrum of examples 12 to 13 of the present invention;

FIG. 3 is a current density-voltage curve for examples 12-13 of the present invention;

FIG. 4 is a graph of current density versus external quantum efficiency for examples 12-13 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples, which are not intended to limit the present invention in any manner. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.