Modulation of trap distribution by optimizing Mn²⁺ doping in CsCdCl₃ crystals toward enhanced afterglow performance

Exploring efficient and stable long-persistent luminescence (LPL) materials is of great value for promoting their advanced applications. Here, the metal halide CsCdCl3:Mn2+ crystals with tunable afterglow properties and good stability were grown by a facile solution method. Upon ultraviolet excitation, CsCdCl3:Mn2+ crystals exhibited a bright orange emission at 590 nm from the d-d transition of Mn2+ ions. Mn2+ doping concentrations matter for the LPL performance. By optimizing the doping amount of Mn2+, an enhanced afterglow duration up to 12 000 s was achieved, compared with undoped sample, originating from a trap redistribution. The deep traps in CsCdCl3:0.1Mn(2+) crystal that provide little contribution to the LPL at room temperature shifted to shallow levels, thus synergistically enhancing the afterglow intensity and duration. Based on the variable afterglow durations by tuning Mn2+ doping concentrations, a multi-dimensional information storage encryption model was designed. This work gives deep understanding in doping effect on the afterglow and provides examples for the development of multi-dimensional information encryption.