A novel Bi3+,Eu3+ co-doped Ca3Zr2SiGa2O12 phosphors for high-sensitive temperature measurement

High-sensitive optical thermometers have garnered significant attention due to rapid technological advances. Here, novel Bi³⁺,Eu³⁺ co-doped Ca₃Zr₂SiGa₂O₁₂ (CZSG) phosphors with high temperature sensitivity were synthesized. Extensive researches of structure, photoluminescence and mechanism of energy transfer from Bi³⁺ to Eu³⁺ in CZSG:Bi³⁺,Eu³⁺ were carried out. Under excitation of 291 nm light, a broadband at 310–400 nm from Bi³⁺ ions as well as peaks at 580–710 nm from Eu³⁺ ions are both observed in CZSG:Bi³⁺,Eu³⁺. Fluorescence intensity (FI) of Bi³⁺ and fluorescence intensity ratio (FIR) of Bi³⁺ and Eu³⁺ were used to design dual-mode optical thermometer. The maximal relative sensitivities (S_R) are 2.98%K⁻¹ @ 573 K (FI) and 1.88% K⁻¹ @ 303 K (FIR), respectively. Noticeably, when two modes are combined, the minimal S_R of CZSG:Bi³⁺,Eu³⁺ is higher than 1.04%K⁻¹ over the whole temperature range (303–573 K). Above results indicate the potential application of CZSG:Bi³⁺,Eu³⁺ sample in optical thermometers.