Optical Temperature Sensing Based on Linear Change of Luminescence Intensity Ratio in Y2O3: Tm3+, Eu3+ Phosphors.

Abstract

In this work, Y2O3: Tm3+, Eu3+ phosphors were made by homogeneous precipitation with urea as precipitator. The emission spectra varying with temperature of Y2O3: Tm3+, Eu3+ phosphors were measured and analyzed. Analysis show that the luminescence of Eu3+ represents a normal thermal quenching change, while that of Tm3+ exhibits slow thermal enhancement phenomenon. In the temperature range of 303-503K, the luminescence of Tm3+ showed a trend of first strengthening and then weakening. The reason for this phenomenon of Tm3+ is that there is energy transfer from Eu3+ to Tm3+, and the energy transfer efficiency increases gradually with temperature. Meanwhile, the luminescence of Tm3+ also have thermal quenching effect. Under the combined influence of thermal quenching and energy transfer, the luminescence of Tm3+ first becomes stronger and then then becomes weaker. According to the calculation, the luminescence intensity ratio (LIR) of Tm3+ and Eu3+ conforms to the linear empirical formula with increasing temperature. The relative sensitivity of phosphors decreases with Eu3+ concentration increased, and the maximum Sr reaches 0.460% K-1 (1% Tm3+, 0.3% Eu3+, at 303K). Moreover, the temperature cycle test present that the LIR of phosphors has good repeatability.