Nitrogen-containing heterocyclic compounds and their applications and organic electroluminescent devices

Abstract

The disclosure relates to a nitrogen-containing heterocyclic compound, which has a structure shown in the following formula (1): The nitrogen-containing heterocyclic compound of the present disclosure includes an asymmetric carboline group and a carbazole group, so that the molecule At the same time, it has excellent hole and electron transport properties; at the same time, bridged N heterocycles and electron-withdrawing groups such as triazine, benzocyano, pyrazine, and pyridine cyano are introduced into the molecular structure, which contributes to the molecular electron transport ability. improvement. The nitrogen-containing heterocyclic compound has excellent bipolar transport ability, can broaden the charge recombination area, and reduce the efficiency roll-off; and through the introduction of different kinds of carboline groups, as well as the The change of the relative substitution position can regulate the energy level of the compound, so that materials with different energy levels can be screened, and it is easy to select and match device materials.

Description

technical field [0001] The present disclosure relates to the field of organic electroluminescent materials, in particular, to a nitrogen-containing heterocyclic compound, its application and an organic electroluminescent device. Background technique [0002] The research on organic electroluminescent materials and devices began in the 1960s. According to different luminescent principles, organic electroluminescence can be divided into two categories: electroluminescence and electrophosphorescence. The triplet excitons of fluorescent materials are subject to spin prohibition, and can only return to the ground state in a non-radiative form to generate photons, resulting in the internal quantum efficiency of electroluminescence being limited to within 25%. Electrophosphorescence can make full use of the energy of singlet excitons and triplet excitons, so theoretically the internal quantum efficiency of phosphorescent devices can reach 100%. In 1998, Ma et al. of Hong Kong Uni...

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Problems solved by technology

[0004] However, the current thermally activated delayed fluorescence (TADF) materials have a mismatch between the hole transport ability and the electron transport ability, and the reverse intersystem crossing rate (k RISC ) is low, triplet-polaron annihilation (TPA) is more serious, etc.

[0005] In addition, in organic electroluminescent materials, its hole transport ability is often better than electron transport ability, which leads to unbalanced electron and hole transport and affects the luminous efficiency of electroluminescent devices.

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