Raman and photoluminescence intensity ratio: A tool for high temperature optical thermometry in Ba2Y2/3TeO6: Eu3+ double perovskites

Ratiometric thermometry based on lanthanide-activated phosphors is the most reliable method to measure the thermometric figures of merit due to its self-referencing ability. In this work, we use the rarely investigated Raman and photoluminescence intensity ratio (RPIR) method to evaluate the high-temperature sensitivity of a double perovskite phosphor Ba2Y2/3TeO6: 2.5% Eu3+ for the first time. The phosphor exhibits a maximum relative sensitivity of 0.52% K−1 at 573 K with a temperature resolution of 0.17 K. The study proved the RPIR method as a promising strategy for high-temperature optical thermometry using crystalline solids.