Photostimulated Ultraviolet Luminescence for Anti-Counterfeiting in Daylight Conditions

Photostimulated luminescence in the ultraviolet (PSL-UV) holds promise for high-security anti-counterfeiting applications, especially in brightly lit environments. Despite its potential, research on PSL-UV is relatively limited. Here, the PSL-UV properties of a NaYF₄:Gd³⁺ fluoride-based phosphor is explored, demonstrating its suitability for advanced anti-counterfeiting purposes. This phosphor effectively captures excitation energy from X-rays and subsequently emits UV light at 311 nm when stimulated by visible ambient light. Remarkably, the material exhibits exceptional reliability and durability, maintaining effectual PSL-UV output even after enduring exposure to 100 cycles of ambient light and subsequent decay. Furthermore, ultraviolet imaging experiments highlight the practicality of PSL-UV for real-world implementation, presenting a fresh and robust strategy for enhancing security and authentication processes.