Exciton harvesting in quasi-2D perovskite light-emitting diodes with an encapsulated thermally activated delayed fluorescence

Abstract

The poor exciton harvesting is a key reason for the poor performance of quasi-2D perovskite light-emitting diodes (PeLEDs). Here, an encapsulated thermally activated delayed fluorescence (TADF) is involved to solve this problem by a solution processed doping method. The maximum current efficiency of optimized PeLEDs is 5.32-fold to that of the pristine one. It is found that the energy funneling process, the Förster energy transfer process, and the reverse intersystem crossing process were working together to improve exciton harvesting. Moreover, the quasi-2D perovskite can be protected from water and oxygen due to the surrounded encapsulated TADF emitters.