Low-cost dual-emissive phosphors with UV-to-visible persistent luminescence for information encryption and advanced anti-counterfeiting

Dual-emissive long persistent luminescence (LPL) phosphors with ultraviolet (UV)-to-visible persistent luminescence (PersL) are increasingly studied for high-performance information security. However, their high production cost limits practical application in optical information security. Here, we report a low-cost dual-emissive LPL phosphor, CdSiO 3 :Bi 3+ ,Pr 3+ , displaying characteristic UVA PersL peaking at 362 nm from Bi 3+ and red PersL peaking at 606 nm from Pr 3+ after 254 nm UV excitation. The UVA PersL decays within 600 s, whereas the red PersL persists beyond 2 h. The cost advantage of this phosphor stems from its simple chemical composition, inexpensive raw materials, and a calcination temperature as low as 950 °C. Thermoluminescence analysis indicates that charge-imbalanced substitution of Cd 2+ by Bi 3+ and Pr 3+ ions increases the concentration of shallow electron traps and introduces deeper electron traps, thereby enhancing the PersL performance in doped CdSiO 3 relative to its undoped counterpart. Leveraging the inherent UV-to-visible dual-emissive PersL for encryption, we demonstrate a triple-modal encryption-decryption strategy using a commercial red fluorescent powder, UVA-emitting CdSiO 3 :Bi 3+ , and dual-emissive CdSiO 3 :Bi 3+ ,Pr 3+ LPL phosphors. This work presents a design pathway for affordable UV-to-visible dual-emissive LPL phosphors, thereby advancing their potential in dynamic optical information security and anti-counterfeiting applications.