Influence of Yb3+ percentage on emission of Er3+ doped into GdVO4 matrix

Abstract

In this study, we used the non-hydrolytic sol–gel methodology to synthesize gadolinium vanadate particles doped with different Er3+ and Yb3+ molar ratios. Er3+ and Yb3+ chlorides and vanadium alkoxide were used as precursors during the sol–gel synthesis. The resulting powders were treated at 800 °C and characterized by x-ray diffraction and photoluminescence. The x-ray diffractogram displayed peaks attributed to the gadolinium vanadate matrix. Photoluminescence helped to evaluate the Fluorescence Intensity Ratio (FIR), which is important for understanding the nanothermometer property. The FIR of the GdVO4:Er3+/Yb3+ samples containing different Er3+ and Yb3+ molar ratios increased as a function of the laser power, which indicated that the local temperature increased. The excitation spectra obtained at fixed wavelengths of 525 and 555 nm displayed bands at 322, 379, and 489 nm, ascribed to the charge transfer band and Er3+ levels. Upon excitation at 321 nm, the emission spectra in the visible region presented intense bands at 525 and 555 nm, due to Er3+ emission, and excitation at 321 nm led to emission in the infrared region, 980 and 1550 nm. In conclusion, the synthesized system can be employed as a temperature sensor.