Highly Sensitive Dual-Mode Optical Thermometry in Double-Perovskite Oxides via Pr3+/Dy3+ Energy Transfer.

As increasing demand for noncontact temperature sensing, the development of a high-performance optical thermometer probe is more and more urgent. In this work, an efficient dual-mode optical thermometry strategy based on the Pr3+/Dy3+ energy transfer (ET) in some typical double-perovskite oxides is presented, which offers a promising way to design FIR/lifetime dual-mode optical thermometry with excellent temperature-measuring sensitivity and signal discrimination. According to this strategy, double-perovskite La2MgTiO6:Pr3+/Dy3+ phosphors are successfully synthesized. On the basis of diverse thermal responses between Pr3+ and Dy3+, the FIR of Pr3+ to Dy3+ (four FIR mode) in this material displays outstanding optical thermometry performance from 298 to 548 K. The maximum absolute and relative sensitivities (Sa and Sr) of mode 1 are 0.09 and 2.357% K-1, being better than the current optical temperature measurement materials. For the fluorescence lifetime mode, the Sa-max and Sr-max values reach 2.85 × s 10-4 and 1.814% K-1. Furthermore, the dual-mode optical thermometry mechanism was presented and studied. It also demonstrated excellent optical thermometry performance in the other Pr3+/Dy3+ codoped double-perovskite oxides, such as LaMg0.598Nb0.402O3, NaLa(MoO4)2, NaGd(MoO4)2, and NaLa(WO4)2, proving the universality of the presented strategy. This article presents an effective Pr3+/Dy3+ ET pathway for developing new and highly sensitive FIR/lifetime dual-mode optical temperature sensing materials.