Novel organic light-emitting materials aimed for electroluminescence

—High-efficiency reverse intersystem-crossing from triplet into singlet excited states—

Abstract

We report on a material possessing a very small energy gap between its singlet and triplet excited states, δE_1-3, which allows on efficient up-conversion of triplet excitons into a singlet state and leads to on efficient thermally activated delayed fluorescence (TADF). We propose a molecular design that realizes a very small δE_1-3 while maintaining a high fluorescent radiative decay rate. The intense TADF provides a pathway for highly efficient organic electroluminescence.