Citrate-based sol-gel synthesis of blue- and green-emitting BaLa2WO7:Tm3+ or Er3+ phosphors and their luminescence properties

BaLa2WO7:Tm3+ or Er3+ (BLWO:Tm3+ or Er3+) single doped phosphors were prepared by a citrate-based sol-gel method. The crystalline properties of the prepared blue- and green-emitting phosphor materials were analyzed by X-ray diffraction (XRD) after annealing at 1350 degrees C. The XRD patterns of the both phosphors revealed monoclinic structure with a space group of P21/b. The morphological properties and elemental mappings of the BLWO:0.02Tm(3+) and BLWO:0.01Er(3+) phosphors were measured by field emission scanning electron microscope images and energy dispersive X-ray spectrum, respectively. The photoluminescence (PL) spectra of BLWO:Tm3+ phosphors showed characteristic emission peaks of Tm3+ ions from the visible blue to near-infrared regions with the dominant emission at 799 nm (H-3(4) -> H-3(6)) under ultraviolet (UV) and near-UV excitation wavelengths. Similarly, Er3+ ions activated BLWO phosphors exhibited intense green emissions at 548 nm (S-4(3/2) -> I-4(15/2)) under the characteristic excitation wavelength of 381 nm. Furthermore, the temperature-dependent PL emission spectra and the luminescence decay curves were measured for the optimized BLWO:0.02Tm(3+) and BLWO:0.01Er(3+) phosphors. The chromaticity coordinates for the optimized blue- and green-emitting phosphors were calculated. (C) 2017 Elsevier Ltd. All rights reserved.