Improving the temperature-sensing performance of the SrZn0.33Nb0.67O3:Pr3+ phosphor via Ga3+ doping

Optical thermometry offers promising applications in the fields of microelectronics and biomedicine, as well as in fire pre-warning systems. In this research, Pr3+-activated SrZn0.33Nb0.67O3 phosphors were successfully prepared via solid-state reactions. Under ultraviolet excitation, the SrZn0.33Nb0.67O3:x%Pr3+ (x = 0.25/0.75/1.25/2) phosphors exhibit bright blue and red emissions, located at 491 nm (3P0 → 3H4), 619 nm (1D2 → 3H4) and 651 nm (3P0 → 3F2). Specifically, two fluorescence intensity ratio (FIR) models of 1D2 → 3H4versus3P0 → 3H4 (Red1/Blue) and 1D2 → 3H4versus3P0 → 3F2 (Red1/Red2) in the temperature range of 300–500 K are adopted for temperature sensing. Our results show that the designed phosphor can serve as a novel potential self-calibrated optical thermometer. Moreover, the temperature sensitivity of the FIR thermometer is significantly enhanced when Ga3+ is incorporated into the SrZn0.33Nb0.67O3. Specifically, the maximum absolute and relative sensitivity for the 6% Ga3+ co-doped sample are increased five- and two-fold, respectively, compared with the undoped sample. This work may provide useful inspiration for effectively improving the temperature-sensing performance of optical thermometers.