Tuning excited state energy levels by achieving coordination-induced thermally activated delayed fluorescence

Abstract

In this study, a low steric hindrance spiro-type diimine ligand, which possesses long afterglow, has been prepared to design Ag(I) complexes. By achieving coordination-induced thermally activated delayed fluorescence (TADF), the excited state energy level of the spiro-type diamine ligand is regulated, and a small ΔE_ST is obtained. Thus, a reverse intersystem crossing (RISC) process is facilitated and an highly efficient TADF is achieved in these Ag(I) complexes. This mechanism, illustrated in this study, contributes to an in-depth understanding of transformations in different radiative decay pathways.