Mn and Li co-doped CaO introduces complex trap energy levels and luminescent channels for optical anti-counterfeiting

Multimodal optical anti-counterfeiting plays a vital role in modern commodity circulation. However, most current multimodal anti-counterfeiting materials rely on complex multi-component compounds and costly rare-earth ion doping, which limits their commercial applications. Therefore, achieving multimodal anti-counterfeiting within simple and low-cost compound systems holds promising practical prospects. This work developed luminescent materials with multimodal emission and optical storage capabilities via Mn 2+ single doping and Li-flux modification of an inexpensive and readily available CaO host. Calcium oxide is a common industrial product that can be obtained through simple calcination, laying the foundation for practical commercial applications. The Mn 2+ singly-doped sample enables information writing via ultraviolet light and dual-mode (thermal/optical) readout, a property not shared by the Li-flux modified counterpart. Furthermore, based on the flux effect, Li-flux treatment not only enhances the green emission of Mn 2+ but also introduces deeper traps, extending storage duration and enabling high-temperature readout. Leveraging the differences in optical response and trap distribution between the two materials, a multi-level optical anti-counterfeiting demonstration with dynamic color and temperature-dependent characteristics was constructed. This work provides a new material strategy for developing low-cost, high-security optical anti-counterfeiting and information encryption technologies.