A linear calibrated high temperature sensor based on up-conversion fluorescence of Y2Mo3O12:Er3+,Yb3+ enhanced by negative thermal expansion

The temperature sensing properties of the Y 2 Mo 3 O 12 :Er 3+ ,Yb 3+ phosphor are analyzed by using fluorescence intensity ratios (FIRs) of up-conversion (UC) emissions of Er 3+ from room temperature to 753 K. The negative thermal expansion phenomenon is confirmed above 393 K in this phosphor, which results in great enhancement of UC emissions with high temperatures despite thermal quenching. Moreover, the FIRs of emission peaks derived from Stark-splitting sub-levels are applied to improve temperature sensing performance. In this way, the optimum of absolute and relative sensitivities reach 1.303*10 −2 K −1 and 1.139%∙ K −1 , respectively. In addition, each FIR of emission peaks has a linear relationship with temperature, which is simple and easy to be calibrated. • Negative thermal expansion enhanced emission is used for high-temperature sensing. • Sensing performance is improved by FIRs for Stark-splitting sublevels. • Each FIR linearly depends on temperature, simple and easy to be calibrated.