Preparation and Photoluminescent Properties of Tb3+-Doped Lu2W3O12 and Lu2Mo3O12 Green Phosphors

Tungstate and molybdate phosphors have received great attention for their excellent photoluminescent properties and thermal stabilities. In the article, Tb3+-activated tungstate and molybdate green phosphors were prepared by a solid-state reaction method at different caline temperatures and were compared and studied. The crystal structures and the morphologies of samples were characterized by X-ray diffraction (XRD) patterns and field emission scanning electron microscopy (FE-SEM) images. The energy-dispersive spectra (EDS) proved the compositions of the prepared samples. The photoluminescence (PL) spectra showed that the PL excitation spectra of Tb3+-doped Lu2W3O12and Lu2Mo3O12green phosphors consisted of a broad and strong charge transfer band (CTB) and 4f–5d transitions of Tb3+in the ultraviolet (UV) wavelength range and some narrowed excitation peaks from the 4f–4f transition of Tb3+in the near ultraviolet (NUV) wavelength region. The PL emission spectra of the phosphors exhibited the characteristic green emissions owing to the5D4→7F5transition of Tb3+located at about 547 nm. The values of energy gapEgwere calculated based on the diffuse reflection spectra (DRS). The measuring temperature-dependent PL spectra illustrated the thermal stabilities of phosphors. The Tb3+-doped Lu2Mo3O12phosphor presented normal thermal quenching phenomena and the values of the thermal activation energyEawere calculated based on the measuring temperature dependent PL emission spectra. The Tb3+-doped Lu2W3O12phosphor exhibited abnormal thermal enhancing CTB excitation intensity at about 170 °C. Furthermore, the PL decay curves suggested that the lifetime corresponding to the5D4level of Tb3+in the Lu2W3O12host lattice was longer than that in the Lu2Mo3O12host lattice. Compared the Tb3+-doped Lu2Mo3O12phosphor, the Tb3+-doped Lu2W3O12phosphor has shown potential as an application in temperature sensors.