Synthesis and photoluminescence properties of Ca3R2−xWO9:xEu3+ (R=Y, Gd) phosphors

Ca3R2–xWO9:xEu3+ (R=Y, Gd) red-emitting phosphors were prepared by solid state reactions. These samples were characterized by differential scanning calorimetry and thermogravimetry analysis (DSC-TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and field emission scanning electron microscopy (FE-SEM) analyses. The optimum sintering temperature for these phosphors was 1100 °C, and the optimum sintering time was 2 h. The optimum doped concentration of Eu3+ in Ca3Y2–xWO9:xEu3+ and Ca3Gd2–xWO9:xEu3+ were x=1.5 and x=1.1, respectively. These phosphors could be excited by near-UV light of 394 nm and blue light of 465 nm, and showed strong red emission line at 612 nm (5D0→7F2), which indicated that Ca3R2–xWO9:xEu3+ (R=Y, Gd) were promising red candidates for white LED.

Graphical AbstractExcitation and emission spectra of CaY0.5W:1.5Eu3+ (a) and CaGd0.9W:1.1Eu3+ (b)Figure optionsDownload full-size imageDownload as PowerPoint slide