No-Interference Reading for Optical Information Storage and Ultra-Multiple Anti-Counterfeiting Applications by Designing Targeted Recombination in Charge Carrier Trapping Phosphors

Charge carrier trapping phosphors are one of the most fascinating candidates for next-generation optical information storage technology and advanced anti-counterfeiting applications. However, there is a challenge in that shallow traps can result in interference with the real-time reading of optical information, and the anti-counterfeiting level also needs to be further enhanced. Here, a novel quasi-layer-structured Ca 3 Ga 4 O 9 :Bi 3+ phosphor is introduced to address this challenge, based on the targeted recombination phenomenon. This material shows turning electron-trapping ability and obvious differences in photoluminescence, long persistent luminescence, and photo-stimulated luminescence processes, which are beneficial in achieving information reading without interference and provide multiple anti-counterfeiting. As a proof of concept, information reading without interference is experimentally achieved by choosing an appropriate filter and excitation wavelength, and multiple anti-counterfeiting applications are demonstrated using a simple seal-photocopy method. The results indicate that the targeted recombination strategy is very effective for achieving multifunctional applications of charge carrier trapping phosphors.