Heterocyclic compound based on carbazole and fluorene, application thereof and organic electroluminescent device

Abstract

The invention relates to a heterocyclic compound based on carbazole and fluorene, the compound having a structure shown as a formula (1). In the compound, connection of carbazole and fluorene througha sigma bond does not cause a large increase in the degree of conjugation, the compound can still has a high triplet state energy level, can be used as a main material of red, green and blue luminescent materials, has a narrow energy gap, which is favorable for carrier injection and can effectively reduce the cut-in voltage of the device. The molecular structure contains a group having a positiveHammett value, thus greatly improving the electron transporting ability of the molecule, expanding the carrier recombination zone when the compound is utilized in a light emitting layer of the organicelectroluminescent device, and effectively reducing the efficiency roll-off. Fluorenyl is connected to carbazole in the compound, and the whole molecule has a large rigid distortion structure, and therefore, quenching caused by aggregation can be effectively reduced, and the light emitting efficiency of the organic electroluminescent device can be increased.

Description

technical field [0001] The present disclosure relates to the field of organic electroluminescent materials, in particular, to a heterocyclic compound based on carbazole and fluorene, its application and an organic electroluminescent device. Background technique [0002] In 1987, Professor Deng Qingyun, a Chinese scientist, reported for the first time based on triarylamine and AlQ 3 bilayer organic electroluminescent devices (OLEDs). Compared with traditional liquid crystal displays, OLEDs have many advantages: self-illumination, high contrast, ultra-thin, foldable, low power consumption, etc., so they are considered to be the future of display and lighting technology. [0003] The luminescent materials used in OLEDs have experienced the development of traditional fluorescence, phosphorescence and then thermally activated delayed fluorescence, and the internal quantum efficiency has gradually increased from 25% to 100%. [0004] Among them, thermally activated delayed fluor...

AI Technical Summary

Problems solved by technology

[0006] Since most common host materials have a wide band gap and unipolar transmission characteristics, it often leads to barriers to exciton injection and high turn-on voltage

In addition, due to the unbalanced carrier transport, the exciton coincidence region deviates at high voltage, causing changes in the luminescent spectrum and serious efficiency roll-off problems.

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