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

Abstract 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.