Ba₂YV₃O₁₁ Er³⁺/Yb³⁺ Nanostructures for Temperature Sensing in the Presence of Bismuth Ions

Chemical compounds with high upconversion (UC) intensity are still needed for temperature-sensing media based on the fluorescence intensity ratio (FIR) technique of UC materials. In this work, the citrate-based sol–gel method was used to produce Yb 3+ /Er 3+ –Bi 3+ codoped Ba 2 YV 3 O 11 (BYVO) nanophosphors. Using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, we examined the influence of Bi 3+ ions on the phase structure and morphology of BYVO was examined. Power-dependent photoluminescence (PL) spectroscopy shows how Er 3+ and Yb 3+ transfer energy, and the involved UC mechanism is part of the two-photon stimulation process. Moreover, the improved optical properties of BYVO phosphors were due to the local environment of Er 3+ ions that was modified by the addition of Bi 3+ ions. The emission intensity of these bands is enhanced in the presence of Bi 3+ ions. The FIR method based on Er 3+ thermal coupling level was used to investigate the temperature-sensing performance. The relative sensitivity of the tridoped nanophosphor has been determined to be 1.45% K –1 at 250 K. The incorporation of Bi 3+ could improve the temperature resolution obtained when it is used as a thermometric sensor. The results obtained from the present study indicate that the Er 3+ –Yb 3+ –Bi 3+ tridoped BYVO nanophosphors may be of particular interest in developing near-infrared to visible upconverters, green display devices, and optical nanothermometry.