Opto‐Mechano‐Thermo‐Sensitive Allochroic Luminescence Based on Solution‐Grown Halide Double Perovskite Crystal

Abstract Multimode luminescence generally exhibits tunable photon emission through multidimensional stimuli, demonstrating high‐throughput and facile identification for anticounterfeiting and encryption. Nevertheless, producing multimodal luminescent materials through low‐temperature treatment remains a challenge. Herein, the Mn 2+ /Er 3+ co‐doped Cs 2 Ag 0.8 Na 0.2 InCl 6 perovskite material (reaction temperature of 180 °C) achieves long‐persistent luminescence, multicolor luminescence, and upconversion emission by responding to several types of excitations ranging from UV to NIR and mechanical force. The adjustable energy transfer process between self‐trapped excitons (STE) and Mn 2+ ions achieves multicolor luminescence with temperatures ranging from 97 to 397 K. Theoretical calculation reveals that the important role of Mn 2+ dopants and Na + dopants in the modulation of local electronic environments and the afterglow emission comes from carriers escaping from the trap center (primarily caused by Cl vacancy and interstitial Na) to the local emission center (Mn 2+ ions). This integrated multimodal luminescent material provides a novel direction for the development of multifunctional optical materials and devices.