Competitive Cr <sup>3+</sup> occupation in persistent phosphors toward tunable traps distribution for dynamic anti‐counterfeiting
Mengya Zhang, Zhijun Wang, Xuejiao Wang, Hao Suo, Lingwei Cao, Yao Yao, Mingjie Zheng, Jia Cui, Zhibin Yang, Panlai Li
Abstract
Abstract Red/near infrared (NIR) long persistent phosphors have received extensive attentions in biomedical, food inspection, iris recognition, biological imaging, etc. Herein, a new phosphor, Li 2 ZnGe 3 O 8 :Cr 3+ , is reported with deep red persistent luminescence peaking at 708 nm. By adjusting the Cr 3+ doping concentration, the competitive site occupation at [ZnO6] and [GeO6] polyhedral enables different traps behaviors including trap types, trap concentration and trap depth, which in turn leads to different afterglow duration time from 2 to 20 h. The persistent luminescence mechanisms originated from different trap models have been discussed, and it is found that they can cooperate or inhibit each other, enabling different luminescence depending on time. The dynamic anti‐counterfeiting applications have been demonstrated, which provides a new way to rationally designing for multi‐functional luminescent materials.