A high-contrast polymorphic difluoroboron luminogen with efficient RTP and TADF emissions
Xin Wang, Xiaofu Wu, Tong Wang, Yuliang Wu, Haiyang Shu, Zhiqiang Cheng, Lei Zhao, Hongkun Tian, Hui Tong, Lixiang Wang
Abstract
-chelated four-coordinated difluoroboron-based emitter is reported with three polymorphs, which emit high contrast green (G), yellow (Y) and red (R) light. Interestingly, the G and R-Crystals show different thermally activated delayed fluorescence (TADF) at 530 nm and 630 nm with a remarkable emission spectral shift of up to 100 nm, while the Y-Crystal exhibits room temperature phosphorescence (RTP) at around 570 nm with a high solid-state quantum yield of 77%. Single crystal analysis and theoretical calculations reveal that different molecular conformations and packing modes lead to distinct triplet exciton conversion channels.