A promising temperature sensing strategy based on highly sensitive Pr3+-doped SrRE2O4 (RE = Sc, Lu and Y) luminescent thermometers

For Pr3+:SrRE2O4 (RE = Lu or Y), the diverse temperature-dependent luminescence properties of the Pr3+ ions located at different sites (RE3+ and Sr2+) demonstrate an excellent temperature sensing capability. In particular, Pr3+:SrY2O4 presents high-performance optical thermometry in the physiological temperature range with good repeatability. [Display omitted] •The crystal-field splitting of Pr3+ ions in SrRE2O4 was investigated in detail.•Pr3+ ions can occupy the Sr2+ and RE3+ sites simultaneously in SrLu2O4 and SrY2O4.•There is energy transfer between Pr3+ ions located at Y3+ (or Lu3+) and Sr2+ sites.•The Pr3+emissions from different doping sites exhibit excellent temperature sensing.•Pr3+:SrY2O4 maintains Sr ≥ 1.90%·K−1 in the physiological temperature range. Pr3+ lanthanide ions show enormous application potential in the optical thermometric field due to the abundant 4f5d → 4f and 4f → 4f transition lines. Pr3+-doped SrRE2O4 (Re = Sc, Lu and Y) luminescent thermometers are proposed in this study, and the relevant site occupancies of dopant Pr3+ ions are investigated based on the temperature-dependent steady-state and transient photoluminescence spectral analyses. The results obtained indicate the Pr3+ ions only enter into the Sr2+ sites in Pr3+:SrSc2O4, whereas can occupy the Sr2+ and RE3+ sites simultaneously in Pr3+:SrLu2O4 and Pr3+:SrY2O4. Meanwhile, the dependence of transient decay dynamics analyses on temperature further verifies the existence of the energy transfer mechanism between Pr3+ ions located at Y3+ (or Lu3+) and Sr2+ sites. The luminescence thermometry strategy on the basis of the 3P0 → 3H4 emissions from different Pr3+-doped sites (RE3+ and Sr2+) in Pr3+:SrLu2O4 and Pr3+:SrY2O4 exhibits high-performance temperature sensing, yielding a maximum relative sensitivity Sr of 1.63%·K−1 (400 K) for Pr3+:SrLu2O4 and 3.30%·K−1 (300 K) for Pr3+:SrY2O4. Moreover, Pr3+:SrY2O4 manifests excellent sensing performance in the physiological temperature range with a Sr value no lower than 1.90%·K−1. The temperature sensing approach discussed in this research would facilitate the development of new Pr3+-based sensing strategies.