Truxene-linked coumarin-corrole triad: Synthesis, photophysical properties and application in Triplet−Triplet annihilation upconversion

Abstract

It is crucial to develop organic triplet photosensitizers (PSs) with excellent performance for upconversion applications. Herein, we synthesized a novel truxene-linked coumarin-corrole triads (C-Trux-Corr) and investigated the photophysical properties by steady-state UV–Vis absorption and fluorescence spectroscopies as well as nanosecond time-resolved transient absorption spectroscopy. The triad displays an efficient intramolecular singlet energy transfer from coumarin moiety to the corrole moiety. Nanosecond time-resolved transient difference absorption spectra indicate that the triplet excited states of C-Trux-Corr are distributed on the corrole moiety. The triplet lifetimes of C-Trux-Corr and Trux-C are 195.2 μs and 45.9 μs, respectively. The triplet state lifetime of C-Trux-Corr is significantly prolonged and it was applied as an organic triplet photosensitizer in the triplet-triplet upconversion system with an upconversion quantum yield of 2.93%, which is higher than that the corrole itself (1.27%) by more than 2-fold.