Tuning the energetics of carbonyl-bridged triarylamines: from thermally activated delayed fluorescence to anti-Kasha dual-emission and room temperature phosphorescence materials

The first example of tuning the energetics of thermally activated delayed fluorescence (TADF) molecules to access anti-Kasha dual-emission and room-temperature phosphorescence materials through a strategy for structural modification is developed here. To rapidly construct a library of structurally diverse carbonyl-bridged triarylamine-based TADF materials, the copper-mediated cyclization of heterocycles and 2-bromobenzoic acids was further developed for the first time. Novel anti-Kasha dual-emission materials exhibit distinct white light emission with CIE coordinates of (0.32, 0.32) in the solid film and can be fabricated into low-cost and robust organic white LEDs. Ultralong room temperature organic phosphorescence (URTP) materials displayed a cyan afterglow for up to seven seconds with a lifetime of 508.8 ms and could be used in encryption.