Optical thermometry based on Li plus enhanced up-conversion luminescence performance of Y2O3: Er3+phosphors

A series of Er3+/Li+ co-doped Y2O3 phosphor samples were synthesized by using a low-temperature combustion method. The morphology, crystal structure, up-conversion (UC) luminescence properties, and temperature sensing performances are analyzed. The prepared samples exhibit robust UC luminescence bands peaking at 539, 564, and 661 nm excited by an 808 nm laser. The co-doping of Li + ions leads to a remarkable enhancement in the UC luminescence performance of the samples. The optimal doping concentration of Er3+ ions in Y2O3: Er3+, Li+ phosphor samples is 10 mol%. Based on the fluorescence intensity ratio (FIR) method, the temperature sensing performance of Y2O3: 10 % Er3+, 10 % Li+ samples are investigated with respect to the thermal coupling energy levels (TCELs) and non-thermal coupling energy levels (NTCELs) of Er3+ ions. The optimized phosphor sample shows high sensitivity at 138-528 K. These findings offer a potential strategy for enhancing the temperature sensing performance of rare-earth (RE) doped materials and provide valuable insights for developing efficient temperature sensing materials.