Preparation and fluorescence properties of Yb3+ and Er3+ co-doped GdAlO3 phosphors

Yb3+ and Er3+ co-doped GdAlO3 phosphors are prepared by the sol–gel method. The effect of doping concentration on the structure and fluorescence properties is investigated by X-ray diffraction (XRD) and photoluminescence, respectively. XRD pattern indicates that the sample structure belongs to orthorhombic. The photoluminescence results show that both green and red fluorescence emission and upconversion emission intensities decrease with an increase in Yb3+ concentration due to the cross-relaxation process between Yb3+ and Er3+ ions. Based on the emission spectra, the mechanism of the upconversion emission is discussed, and we concluded that the upconversion emission is a two-photon process.