Title

Intramolecular Charge Transfer Controls Switching Between Room Temperature Phosphorescence and Thermally Activated Delayed Fluorescence.

Authors

Chen, Chengjian; Huang, Rongjuan; Batsanov, Andrei S.; Pander, Piotr; Hsu, Yu‐Ting; Chi, Zhenguo; Dias, Fernando B.; Bryce, Martin R.

Abstract

Chemical modification of phenothiazine‐benzophenone derivatives tunes the emission behavior from triplet states by selecting the geometry of the intramolecular charge transfer (ICT) state. A fundamental principle of planar ICT (PICT) and twisted ICT (TICT) is demonstrated to obtain selectively either room temperature phosphorescence (RTP) or thermally activated delayed fluorescence (TADF), respectively. Time‐resolved spectroscopy and time‐dependent density functional theory (TD‐DFT) investigations on polymorphic single crystals demonstrate the roles of PICT and TICT states in the underlying photophysics. This has resulted in a RTP molecule OPM, where the triplet states contribute with 89 % of the luminescence, and an isomeric TADF molecule OMP, where the triplet states contribute with 95 % of the luminescence.

Subjects

PHENOTHIAZINE derivatives; INTRAMOLECULAR charge transfer; PHOSPHORESCENCE; DELAYED fluorescence; TIME-resolved spectroscopy

Publication

Angewandte Chemie, 2018, Vol 130, Issue 50, p16645

ISSN

0044-8249

Publication type

Academic Journal

DOI

10.1002/ange.201809945