Regulating afterglow of LiGa5O8:Cr3+ for dynamic anti-counterfeiting

Fluorescent materials are widely used in the field of anti-counterfeiting. However, conventional fluorescent materials are limited in anti-counterfeiting applications due to their static mode. Here, LiGa5O8:Cr3+ phosphors were prepared at different calcination temperatures by high-temperature solid-state reaction and further fabricated into dynamic anti-counterfeiting films. Samples can emit red light with main emission peak at 719 nm due to 2E → 4A2 transition of Cr3+ ions. By adjusting calcination temperature from 1300 °C to 1550 °C, red afterglow of the film was controlled with respect to luminescence intensity and duration. In addition, 1450 °C was identified as the optimum calcination temperature to prepare LiGa5O8:Cr3+ phosphors with the best luminescent performance. Based on this control strategy, the application of LiGa5O8:Cr3+ in the field of dynamic anti-counterfeiting can be realized.