Recently, near-infrared phosphors that can be applied in many fields such as night vision, agriculture, and bio-applications have attracted considerable interest in the research field worldwide. Herein, a multi-functional and...

Near-infrared spectroscopy is developing rapidly in the fields of human detection and food analysis due to its fast response and non-invasive characteristics.

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.

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