Design strategies for materials showing thermally activated delayed fluorescence and beyond: Towards the fourth-generation OLED mechanism

Abstract

Design strategies for molecules showing thermally activated delayed fluorescence (TADF) are discussed, and a new emitter concept based on an almost “zero-energy-gap” is developed. Thermal activation is not substantial. Applied in an organic light emitting diode, all singlet and triplet excitons are harvested directly in the lowest singlet state without time-delaying TADF. This landmarking mechanism, being beyond TADF, leads to emission decay times in the sub-μs range.