Synthesis, structure and NIR luminescence properties of Yb3+ and Bi3+-activated vanadate GdVO4

Abstract

Near-infrared emission of Yb3+ and Bi3+-co-doped GdVO4 vanadate phosphors obtained via the modified Pechini's method was reported. The phase purity and structure of samples were characterized by X-ray powder diffraction (XRD), X-ray energy dispersion spectroscopy (EDS), scanning electron microscopy (SEM), Raman and infrared (IR) spectroscopy. Photoluminescence emission (PL) and excitation (PLE) spectra were recorded and investigated in details. Results indicated that upon near-UV excitation (340 nm) in the (Bi3+-V5+) charge transfer state this phosphor had a strong broad band yellow-green emission (3P1→1S0) of Bi3+ ions and also NIR emission (2F5/2→2F7/2) of Yb3+ ions in the range of 950–1050 nm, which matched well with the spectral response of the silicon-based solar cells. The decreasing Bi3+ emission with increasing Yb3+ concentration proved the occurrence of energy transfer from Bi3+ to Yb3+ ions. Results demonstrated that Yb3+ and Bi3+-co-doped GdVO4 vanadate phosphors might act as a NIR down-conversion (DC) solar spectral converter to enhance the efficiency of the silicon-based solar cells.