Highly Efficient and Ultralong Afterglow Emission with Anti‐Thermal Quenching from CsCdCl3 : Mn Perovskite Single Crystals

Abstract Triplet exciton‐based long‐lived phosphorescence is severely limited by the thermal quenching at high temperature. Herein, we propose a novel strategy based on the energy transfer from triplet self‐trapped excitons to Mn 2+ dopants in solution‐processed perovskite CsCdCl 3 . It is found the Mn 2+ doped hexagonal phase CsCdCl 3 could simultaneously exhibit high emission efficiency (81.5 %) and long afterglow duration time (150 s). Besides, the afterglow emission exhibits anti‐thermal quenching from 300 to 400 K. In‐depth charge‐carrier dynamics studies and density functional theory (DFT) calculation provide unambiguous evidence that carrier detrapping from trap states (mainly induced by Cl vacancy) to localized emission centers (MnCl 6 4− ) is responsible for the afterglow emission with anti‐thermal quenching. Enlightened by the present results, we demonstrate the application of the developed materials for optical storage and logic operation applications.