Optical dual-mode temperature sensing and information encryption applications using a novel color-tunable NaSrLa(PO4)2: Eu2+, Tb3.

Multifunctional fluorescent materials have long been a focus of research. Among these, temperature sensing technology and its associated materials face significant challenges, necessitating the development of a low-cost, highly sensitive, and reliable temperature sensor. In this study, a new matrix material, NaSrLa(PO4)2 matrix via a high-temperature solid-state method. By co-doping with Eu2+ and Tb3+, the spectral color was tuned to achieve emission ranging from blue to green. Subsequently, a dual-mode temperature sensing system was established based on fluorescence intensity ratios and fluorescence decay lifetimes within the temperature range of 298-473 K. The material exhibited a high sensitivity of Sa = 5.7%/K and Sr = 3.4%/K. The fluorescence decay lifetime model showed an increase in Sr sensitivity from 0.6%/K to 0.8%/K, providing a strategy for enhancing relative sensitivity in future research. Finally, the temperature dependence of fluorescence intensity was utilized to explore application potential in fields such as dynamic anti-counterfeiting and information security, resulting in a new multifunctional material.