Luminescence Properties of Y2WO6 and Y2WO6:Yb3+/Er3+ crystals: Self-activation and Upconversion

Abstract

Self-activation and upconversion luminescence properties of monoclinic tungstate Y2WO6 crystals were investigated optical and laser-excitation spectroscopy. The luminescence material of monoclinic Y2WO6 host and Y2WO6:Yb3+/Er3+ with various Er3+ concentration were synthesized via both classical solid state method and facile hydrothermal method. The sodium surfactant dodecyl benzene sulfonate (SDBS) was used to modify the samples to obtain the peculiar morphology during the hydrothermal synthesis process. The crystal structure of the Y2WO6 host and Y2WO6:Yb3+/Er3+ were characterized by X-ray diffraction (XRD) and their morphology features were measured by scanning electron microscopy (SEM). The monoclinic Y2WO6 host shows different emitting color depending on different excitation wavelength due to the possession of two luminescence centers: W-O charge transfer and oxygen vacancy. The emission bands of Er3+ are obtained by excitation at 980 n. The upconversion spectra of the samples were obtained under different excited power from which it is found that the slope values of the power dependent results decrease due to the cross relaxation process as the Er3+ doping concentration increases. The dominant upconversion mechanism of the monoclinic Y2WO6:Yb3+/Er3+ phosphor was further investigated according to the level structures of Yb3+ and Er3+ ions.