Optical temperature sensing properties realized by isotropic negative thermal expansion in ScF3:Tb3+/Eu3+ phosphor ceramics

The anomalous luminescence thermal quenching performance caused by negative thermal expansion has attracted much attention due to the potential application in optical fields . However, the downshifting emissions with abnormal thermal quenching achieved by isotropic negative thermal expansion for optical temperature sensing applications are still lacking. Herein, a large enhancement of red emission and a high temperature sensing performance are realized by isotropic negative thermal expansion in ScF 3 :Tb 3+ /Eu 3+ phosphors ceramics. Specially, a selectively thermal enhanced red emission of Eu 3+ from 5 D 0 → 7 F 2 with hypersensitive transition characteristics could be obtained due to the thermal stimulated lattice distortion . Attributing to the shortening of cation spacing, the energy transfer efficiency between Tb 3+ and Eu 3+ is largely enhanced with the increasing of the temperature from 303 to 473 K. The enhanced energy transfer leads to that the emission of Tb 3+ firstly increases and then slightly decreases, whereas the emission from Eu 3+ has been largely improved. Finally, an optical temperature sensing strategy based on the fluorescence intensity ratio of the sensitizer Tb 3+ (signal ions) and the activator Eu 3+ (referring ions) is designed, attributing to the distinguishable luminescence response to the temperature. The obtained maximum relative sensitivity is 1.04 % K −1 (@303 K). Besides, the sensing strategy based on lifetime mode also suggests a maximum relative sensitivity of 1.00 % K −1 at 343 K. It provides a feasible strategy to obtain an optical temperature sensing material with high emission efficiency at a high temperature, which sheds light on the design of luminescence materials keeping high luminescence stability in a wide temperature range in the fields of optical temperature sensing.