Elevating the upconversion performance of a multiple resonance thermally activated delayed fluorescence emitter via an embedded azepine approach.

ABSTRACT: Multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters hold promise for efficient organic light-emitting diodes (OLEDs) and wide gamut displays. An azepine donor is introduced into the boron-nitrogen system for the first time. The highly twisted conformation of a seven-ring embedded new molecule, TAzBN, increases the intermolecular distances, suppressing self-aggregation emission quenching. Meanwhile, the azepine donor is crucial to achieve a narrow singlet-triplet gap (0.03 eV) as well as boost the reverse intersystem crossing (RISC) rate to 8.50 × 10⁵ s^-1. It is noteworthy that TAzBN demonstrates an impressive photoluminescence quantum yield of 94%. In addition, its nonsensitized OLED displayed a remarkable external quantum efficiency (EQE

SUBMITTER: Chen YK 

PROVIDER: S-EPMC11220617 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature