A novel upconversion luminescence temperature sensing material: Negative thermal expansion Y2Mo3O12:Yb3+, Er3+ and positive thermal expansion Y2Ti2O7:Yb3+, Er3+ mixed phosphor

Abstract Thermal enhancement and quenching of upconversion luminescence of rare earth ions can be realized in the negative expansion and positive expansion hosts, respectively, which is advantage of temperature sensing applications. In this work, the negative expansion Y2Mo3O12:Yb3+, Er3+ and positive thermal expansion Y2Ti2O7:Yb3+, Er3+ phosphors were prepared, respectively. The temperature dependence of upconversion luminescence demonstrated that the green, red and near infrared upconversion luminescence of Y2Mo3O12:Yb3+, Er3+ phosphor increases with the increasing of temperature, while the upconversion luminescence of Y2Ti2O7:Yb3+, Er3+ phosphor decreases upon the 980 nm laser excitation. A novel upconversion luminescence temperature sensor was obtained by the intensity ratio of the upconversion luminescence of negative thermal expansion Y2Mo3O12:Yb3+, Er3+ to the upconversion luminescence of positive thermal expansion Y2Ti2O7:Yb3+, Er3+. The near infrared-red fluorescence intensity ratio (FIR) (I860/I675) was researched in the range from 293 K to 574 K, which suggests that FIR increases with rising temperature. The maximum relative sensitivity (Sr) was 1.61% K−1 in near infrared-red FIR (I860/I675) at 293 K. The result suggests that the mixed phosphor exhibits potential application as a new temperature sensing device.