Study on optical temperature sensing properties of Tb3+, Eu3+ co-doped CaMoO4 phosphor

CaMoO4: 5% Tb3+, x% Eu3+ (x = 0.3, 0.5, 1, 2) phosphors were synthesized successfully via precipitation method. The Temperature-dependent photoluminescence (PL) spectra of the synthesized phosphors were measured. Fluorescence Intensity Ratio (FIR) of Eu3+ to Tb3+ is dependent on temperature, and the FIR increases with the increase of temperature. The Fluorescence Intensity Ratio was used characterize the temperature. When FIR of Eu3+ to Tb3+ is used to characterize the temperature, the sensitivity increases with the increase of Eu3+ concentration. The maximum value of sensitivity is 0.095 K-1 (at 603 K), when the concentration of Eu3+ is 2%. The sensitivity is one order of magnitude higher than common Er3+ activated materials. In addition, the lower concentration of Eu3+, the greater change range of luminescent color of the samples which is reflected from color coordinates.