High-sensitivity luminescent thermometer based on Mn4+/Sm3+ dual-emission centers in double-perovskite tellurate

Precise temperature detection utilizing optical parameters is very important and has accelerated scientific researchers to design more suitable materials for non-contact optical thermometers. However, the obstacles of low sensitivity, narrow temperature range, and poor signal discrimination are the main challenges at present. Herein, a dual-mode optical thermometer via the fluorescence intensity ratio (FIR) and decay lifetime was designed in novel double-perovskite Mn 4+ /Sm 3+ co-doped SrGdLiTeO 6 (SGLT: Mn 4+ , Sm 3+ ) luminescent materials. The crystal structure, elemental mapping, elemental valence, and oxygen vacancy were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and electron paramagnetic resonance, respectively. Under 464 nm excitation, the maximum relative sensitivity (S R ) values based on the FIR and decay lifetime techniques were estimated as 8.69% K −1 @573 K and 1.3% K −1 @520 K, respectively. Markedly, the SGLT:1.2%Mn 4+ , 1.5%Sm 3+ phosphor exhibited a good signal discriminability. This work identified a new type of luminescent material to explore rigorous and valid dual-mode optical temperature sensors with a wide range and high sensitivity.