Heterocyclic compounds based on carbazole and fluorene and their applications and organic electroluminescent devices

Abstract

The present disclosure relates to a heterocyclic compound based on carbazole and fluorene. The heterocyclic compound has the structure shown in the following formula (1): In the heterocyclic compound of the present disclosure, when carbazole and fluorene are linked by a σ bond, no co- The yoke degree has been greatly improved, and it still has a high triplet energy level, which can be used as the main material of red, green, and blue light-emitting materials. The turn-on voltage of the device can be greatly reduced; the molecular structure contains a group with a positive Hammett value, which can greatly improve the electron transport ability of the molecule, and can expand its carrier when used in the light-emitting layer of an organic electroluminescent device. Composite region, effectively reducing the efficiency roll-off; at the same time, the heterocyclic compound of the present disclosure is connected with a fluorenyl group on the carbazole, and the whole molecule presents a large rigid twisted structure, which can effectively reduce the quenching caused by aggregation, and can improve Luminous Efficiency of Organic Electroluminescent Devices.

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 and its application and organic electroluminescent device. Background technique [0002] In 1987, Professor Deng Qingyun, a Chinese scientist, reported the first report based on triarylamine and AlQ. 3 bilayer organic electroluminescent devices (OLEDs). Compared with traditional liquid crystal displays, OLEDs have many advantages: self-luminous, high contrast, ultra-thin, foldable, low power consumption, etc., and thus are considered to be the future of display and lighting technology. [0003] The luminescent materials used in OLEDs have gone through the development process of traditional fluorescence, phosphorescence, and thermally activated delayed fluorescence, and the internal quantum efficiency has gradually increased from 25% to 100%. [0004] Among them, thermally activated delayed fluo...

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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