High refractive index benzoheterocycle compound, organic light-emitting device and display device

Abstract

The present invention discloses a high refractive index benzoheterocycle compound represented by a formula (I), wherein X1 and X2 are respectively and independently selected from O or S; R1-R4 are respectively and independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C2-C30 heterocyclicgroups; and at least one of R1-R4 is not hydrogen or deuterium. Compared with the prior art, the benzoheterocycle compound provided by the invention has a relatively high refractive index, and can beused as an organic covering layer material to effectively improve the external quantum efficiency of an organic light-emitting device and relieve the light-emitting angle dependence of the organic light-emitting device; moreover, the benzoheterocycle compound has a relatively small extinction coefficient in a blue light region and hardly absorbs blue light, so that the light-emitting efficiency is improved; furthermore, the benzoheterocycle compound has a relatively deep LUMO energy level, can be used as an electron transport material, and is beneficial to light extraction of a bottom emitting device.

Description

technical field [0001] The invention relates to the field of organic electroluminescent materials, in particular to a high-refractive-index benzoheterocyclic compound, an organic light-emitting device and a display device. Background technique [0002] After decades of development, organic electroluminescent devices (OLEDs) have made great progress. Although the internal quantum efficiency of OLED is close to 100%, the external quantum efficiency is only about 20%. Most of the light emitted by OLEDs is confined inside the light-emitting device due to factors such as substrate mode loss, surface plasmon loss, and waveguide effect, resulting in a large amount of energy loss. [0003] In top-emitting devices, an organic capping layer (CappingLayer, CPL) can be evaporated on the semi-transparent metal electrode Al to adjust the optical interference distance, suppress the reflection of external light, and suppress the extinction caused by the movement of surface plasmons, thereb...

AI Technical Summary

Problems solved by technology

However, its refractive index is generally below 1.9, which cannot meet the requirements of high refractive index; even if the refractive index meets the requirements, it has strong absorption or large extinction coefficient in the visible light region; amine derivatives with specific structures with high refractive index Although the use of materials and materials that meet specific parameters improves the light extraction efficiency, it does not solve the problems of luminous efficiency and chromaticity at the same time (especially in blue light-emitting elements)

In addition, in order to increase the molecular density and achieve high thermal stability of the existing CPL materials, the molecular structure is designed to be large and loose, and the molecules cannot be tightly packed, resulting in too many holes in the molecular gel during evaporation. , the covering tightness is poor; moreover, it is simply designed as an electronic covering layer material to achieve the effect of electron transmission and light extraction at the same time. Although it saves the preparation cost of the device to a certain extent and can achieve multiple effects, it is not conducive to light Taking it out only slightly improved the luminous efficiency, and the chromaticity did not solve the problem.

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