Abstract
Mn(2+) doped metal halide that can be grown by a facile solution reaction is a promising low-cost afterglow material. However, the afterglow mechanism is still elusive. Using a facile method to modulate afterglow time is still to be explored. In this work, we reveal that the afterglow of Cs(2)Na(0.2)Ag(0.8)InCl(6):y%Mn can be significantly modulated by Mn(2+) concentration. We propose that replacing Ag(+) with Mn(2+) leads to the appearance of interstitial Ag(+), which temporally store the photogenerated electrons (Ag++e-→Ag). After the removal of excitation, the gradual recombination between residual holes and stored electrons [h++Ag++e-→hν+Ag+] explains the afterglow. However, excessive Mn(2+) doping at interstitial sites does not bring about more interstitial Ag(+) but instead introduces nonradiative traps. Therefore, as the Mn(2+) concentration increases, the afterglow time increases from 350 s to 530 s and then decreases to 230 s, reaching a maximum at y = 40. Thus, a dynamic optical information storage and encryption application is demonstrated based on the modulated afterglow time.