Ratiometric optical temperature sensor with wide range and high sensitivity based on the emission of Dy3+ ion-doped Ca5(PO4)2SiO4 phosphor

There is an urgent demand for the development of non-contact optical temperature sensors that possess a wide temperature measurement range and high sensitivity, particularly for extreme environments. In this study, Dy3+-doped Ca5(PO4)2SiO4 phosphors were prepared and comprehensively analyzed. XRD, SEM, EDS, Raman spectrum, as well as excitation and emission spectrum were employed to investigate the structural, photoluminescent, and temperature-dependent properties of the phosphors. Under 349 nm excitation, the luminescence intensity ratio (LIR) of Dy3+ ions at 453 nm (4I15/2) and 480 nm (4F9/2) exhibited a strong correlation with temperature within the range of 296-1073 K. By fitting the FIR of I453 and I480 at different temperatures using Boltzmann equations, we observed a larger energy gap, indicating high relative sensitivity of the synthesized phosphor. Additionally, Ca4.95(PO4)2SiO4: 0.05Dy3+ phosphor shows excellent temperature repetitiveness. These findings highlight the potential applications of Ca5(PO4)2SiO4: Dy3+ phosphors as highly sensitive ratiometric optical temperature sensor over a wide temperature range.