Dual-modal optical temperature sensing based on Sb3+/Mn2+ co-doped Cs2NaYCl6 double perovskites

Optical temperature sensing based on luminescence intensity ratio shows significant potential in achieving accurate temperature detection. In this work, Sb3+/Mn2+ co-doped Cs2NaYCl6 double perovskites were synthesized via a hydrothermal method. Introducing Sb3+ ions to the host significantly enhances the radiative recombination of self-trapped excitons (STEs), resulting in a broad blue emission. The co-doping of Mn2+ ions to the composition leads to a tunable dual-emission in the spectra, originating from the energy transfer between the STEs and Mn2+ ions. The dependence of the dual-emission on temperature is employed for optical temperature sensing. The maximum relative sensitivity, optimal thermal resolution, and optimal thermal repeatability are determined as 1.40 % K-1, 0.002 K and 99.3% at 250 K, respectively. The results indicate that the synthesized Cs2NaYCl6: Sb3+/Mn2+ double perovskites are promising candidates for high-sensitivity optical thermometers.