Difluoroboron locking tactic enhances photo- and electroluminescence of TADF emitter

Abstract

Luminescent organoboron materials have attracted considerable interests in the field of organic light-emitting diodes (OLEDs). However, their applications are limited by their complicated synthetic routes. Herein, a simple and efficient difluoroboron locking tactic was employed to enhance molecular rigidity and electron accepting strength of thermally activated delayed fluorescence emitters. With this tactic, the resulting difluoroboron compound, MBF, exhibited more rigid configuration and higher acceptor strength than the reference emitter of MPA, resulting in nearly three times higher photoluminescence quantum yield in doped film and a bathochromic emission shift of 91 nm in dilute toluene solution. In comparison with the MPA-based reference device, the MBF-based OLED rendered six times higher maximum external quantum efficiency accompanied with an electroluminescence peak at 630 nm.