A new Mn4+/Eu3+ co-doped double-perovskite phosphor for potential application in optical thermometry and wavelength detection

In comparison to conventional thermometers, optical thermometry has gained worldwide interest due to its unique characteristics including high sensitivity, low cost and easy to perform. Herein, a tri-mode optical thermometer is prepared in Mn4+/Eu3+ co-doped double perovskite Sr2CaTeO6 (SCT) for the first time. The phosphor SCT:Mn4+/Eu3+ exhibits two independent emitting bands at 676 nm and 594 nm, with independent thermal quenching mechanisms. Temperature-dependent PL spectra of SCT:0.017Mn4+/0.04Eu3+ were recorded at temperatures ranging from 298–573 K to analyse the fluorescence intensity ratio (FIR)-based temperature sensing properties. At 298 K, the optimal relative sensitivity (Sr) of SCT:0.017Mn4+/0.04Eu3+ is 1.53 % K−1 using 466 nm excitation, and the maximum Sr can reach to be 3.21 % K−1 at 298 K when using 260 nm light as excitation source. Moreover, SCT:0.017Mn4+/0.04Eu3+ has the other modes of temperature sensing based on dual excitation bands and lifetime. Besides, SCT:0.017Mn4+/0.04Eu3+ can be used for optical wavelength sensing the FIR of Mn4+ and Eu3+ with the maximum relative sensitivity at 275 nm is about 10.56 % nm−1. The tri-mode temperature sensing and wavelength detection properties of SCT:0.017Mn4+/0.04Eu3+ make it an extremely sensitive sensing material, which can serve as a model for future researchers.