Luminescence in Er3+/Sm3+-doped Cs₂NaBiCl₆ double perovskite for optical security and temperature sensing

In this paper, a series of Sm 3+ single-doped and Sm 3+ /Er 3+ co-doped lead-free double perovskite cesium sodium bismuthate hexachloride(Cs 2 NaBiCl 6 ) fluorescent materials are successfully synthesized by solvothermal method, and their multimode luminescence properties and temperature sensing properties are systematically studied. The yellow, orange and green tunable luminescence of Cs 2 NaBiCl 6 :Sm 3+ /Er 3+ phosphor are achieved by adjusting the excitation wavelength(380, 410, 980 nm). The material exhibits multi-color luminescence characteristics under different excitation. Moreover, the anti-counterfeit design exhibits robust security and resistance to duplication. Based on the luminescence intensity ratio(LIR) technology, the relative sensitivity(S R ) of Cs 2 NaBiCl 6 :15 %Sm 3+ /20 %Er 3+ reaches 3.06 %K −1 (313 K) under 410 nm excitation. The study provides a new idea for the development of multi-functional lead-free perovskite materials in the field of optical anti-counterfeiting and precision temperature measurement.