Optical temperature sensing properties of Yb3+/Er3+ codoped LaF3 upconversion phosphor

Abstract The structural and optical properties of Er 3+ /Yb 3+ codoped LaF 3 phosphors are investigated using X-ray diffraction (XRD) and upconversion luminescence spectra. The result shows that the hexagonal phase of LaF 3 keep stability at temperature lower than 800 °C in air condition and will be oxidized to be LaOF at higher temperature. Its upconversion emission intensity varies with the doping concentrations of Yb 3+ ions and reaches a maximum at around 7 mol% Yb 3+ . The power-dependent luminescence reveals the possible emission mechanisms and the corresponding upconversion processes. Furthermore, the optical temperature sensing properties of LaF 3 : Er 3+ /Yb 3+ are studied based on the fluorescence intensity ratio (FIR) technique for two thermally coupled levels ( 2 H 11/2 and 4 S 3/2 ) of Er 3+ . The maximum sensitivity is found to be about 0.00157 K −1 at 386 K, revealing this phosphor to be a promising prototype for applications in optical temperature sensing.