Na2GdMg2V3O12:Sm3+ phosphors for three-mode optical temperature sensing

Multi-mode optical thermometry is emerging as a promising technique for accurate temperature measurement. Here, a series of Na₂GdMg₂V₃O₁₂:Sm³⁺ (NGMVO:xSm³⁺) phosphors with dual-emission centers were successfully elaborated. Irradiated by 349 nm light, NGMVO:Sm³⁺ can generate emissions from VO₄³⁻ and Sm³⁺ simultaneously due to energy transfer between them. Benefitting from difference of thermal quenching performance of two luminescent centers, fluorescence intensity (FI), fluorescence intensity ratio (FIR), and Commission Internationale de L'Eclairage coordinate modes of NGMVO:Sm³⁺ thermometer were designed. Maximum relative sensitivities (S_R) are found to be as high as 2.21 %K⁻¹, 2.12 %K⁻¹, and 0.244 %K⁻¹, respectively. Besides, with temperature increasing, S_R values of FI and FIR modes decrease slowly. Their minimal S_R values between 303 and 513 K maintain above 1.36 %K⁻¹ and 1.08 %K⁻¹, respectively. Our findings reveal that NGMVO:Sm³⁺ phosphors have promising applications for multimode temperature senor.