ABSTRACT A comprehensive experimental and theoretical study of a family of dyes of interest for organic light‐emitting diode (OLED) applications is presented. Specifically, we compare the behavior of structurally related dyes obtained by peripheral substitution of a prototypical thermally activated delayed fluorescence (TADF) dye, DMAC‐TRZ. Decorating the donor (DMAC) moiety with two phenyl groups, a blue‐shift of the emission is obtained, as sought, and an increase of the spin–orbit coupling, suggesting amplified TADF. Quite surprisingly, subtle geometrical rearrangements of the two peripheral groups upon photoexcitation suppress again spin–orbit coupling, leading overall to a similar photophysics as DMAC‐TRZ.
Landi et al. (Sun,) studied this question.