Water-dispersed bismuth-doped strontium pyrovanadate phosphor particles with sub-degree celsius thermal resolution

Abstract

Particle-liquid dispersion technique entails a principle analogous to that of an optically thin arrangement of particles, which is applicable in lab-on-a-chip technology, thin coatings for lighting, solar cell sensitization, medical bioimaging, and temperature measurements in fluids. Sr₂V₂O₇:Bi³⁺ phosphor particles demonstrated the ability to luminesce when dispersed in distilled water. X-ray powder diffraction patterns confirmed that the phosphor crystallised in the triclinic phase. Its morphologies and chemical compositions were analysed using field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The luminescence intensity of the phosphor was optimised via annealing at different temperatures and doping with different Bi³⁺ concentrations. The luminescence intensity of water-dispersed phosphor particles exhibited strong thermal quenching in the temperature range of 22 to 60 °C, and the band maximum showed a significant blue-shift. Relative temperature sensitivity determined from the temperature dependence of luminescence lifetime exhibited a high value around ambient temperatures, with a maximum value of 2.56%/°C at 20 °C and 2.13%/°C at 25 °C. These values were highly comparable to lifetime-based relative temperature sensitivities reported in the literature under similar temperature ranges, demonstrating this material's potential for sensitive thermometry applications around ambient temperatures.