Regulating the trap distribution to achieve high-contrast mechanoluminescence with an extended saturation threshold through co-doping Nd3+ into CaZnOS:Bi3+,Li+

The imaging contrast and saturation threshold are drastically improved after co-doping Nd³⁺ into CaZnOS:Bi³⁺,Li⁺. Using this vis-NIR dual-mode ML, a smart ML pencil is fabricated, realizing anti-counterfeiting and bio-stress imaging simultaneously.