Near-UV sensitized NIR emission in Nd3+ and Bi3+ co-doped GdVO4 phosphors

Near-infrared (NIR) luminescent nanophosphor of Nd3+ and Bi3+ co-doped GdVO4 was prepared by a microwave-assisted hydrothermal method. The phase purity and the structure of samples were characterized by an X-ray powder diffraction (XRD). The optical properties were investigated by analysis of the photoluminescence and excitation spectra and by the emission decay measurements. It was found that upon near-UV excitation of the charge transfer state or the Bi3+ ions absorption, a strong broad band yellow-green emission of Bi3+ ions accompanied with NIR emission of Ni3+ ions is observed. Enhancement of the Nd3+ emission through an energy transfer from the (O2- V5+) or the (Bi3+ V5+) charge transfer states to the excited states of Nd3+ ion was noticed and the possible energy transfer mechanisms were discussed. (C) 2017 Elsevier B.V. All rights reserved.