Up-conversion emission properties and unexpected white light emission from Er3+/Yb3+ doped Gd2O3 nanophosphors

Gd2O3 nanopowders doped with Er3+ and Yb3+ were synthesized using the combustion method. X-ray diffraction and scanning electron microscopy were used to estimate the crystallite size and the morphology of the materials. Scherrer and Warren-Averbach calculations were employed to estimate the mean crystallite size and size distribution of the powders. The crystallite size was found to be <100 nm. The down-and up-conversion emission properties of the materials were studied by laser spectroscopy. Results showed that the 1.5 mu m emission of the Er3+ ions broadened with an increasing amount of Yb3+ ions. An n-shape pumping power dependence of the up-conversion emission intensity was observed. Formation of new emission bands and unexpected production of white light emission with increasing excitation power were also observed. The color quality parameters of the obtained visible emission were also measured.