Abnormal thermal quenching and temperature sensing properties of Pr3+ activated gallate phosphors for optical thermometry

Optical thermometry has gained significant attention for its non-invasiveness, high sensitivity, and fast response. Herein, the Pr 3+ activated La 3 SnGa 5 O 14 optical thermometer phosphors were prepared by a high-temperature solid-state method, and their crystal structure, optical properties, and temperature sensitivity of the phosphors were investigated systematically. Under excitation at 450 nm, the La 3 SnGa 5 O 14 : Pr 3+ phosphor exhibits emission bands ranging from the blue to red region. Notably, it was found that the intensity of emission peaking at 530 nm increases with rising temperature, showing a clear inverse temperature dependence compared with the other emission peaks. Based on the abnormal thermal quenching phenomenon, an optical thermometry model was developed using the fluorescence intensity ratio, exhibiting high performance with a maximum relative sensitivity of 0.788 % K −1 and absolute sensitivity of 6.452 % K −1 . This indicates that La 3 SnGa 5 O 14 : Pr 3+ phosphors have potential application value in the field of optical thermometry.