RESUMO
Undoped and Eu(3+) doped BaTa2O6 phosphors were synthesized via solid state reaction method and characterized by using XRD, SEM-EDS and photoluminescence (PL) analyses. The XRD results revealed that the crystal structure of BaTa2O6 allowed up to 10 mol% levels of Eu(3+) ions due to the TTB characteristic network of adjacent octahedrals. SEM-EDS analyses confirmed the formation of BaTa2O6 structure and EuTaO4 secondary phase. BaTa2O6:Eu(3+) phosphors exhibited orange and red emissions at 592.2 nm and 615.7 nm in the visible region respectively. The Commission Internationale d'Eclairage (CIE) chromaticity coordinates of the BaTa2O6:Eu(3+) phosphors that excited at λ ex = 400 nm ranged from orangish-red to pinkish-red depending on increasing Eu(3+) concentration.
RESUMO
Pure, Eu(3+) - doped and Eu(3+),B(3+) co-doped CdNb2O6 powders have been prepared by a molten salt synthesis method using Li2SO4/Na2SO4 salt mixture as a flux at a relatively low temperatures as compared to solid state reaction. X-ray diffraction patterns of pure CdNb2O6 samples indicated orthorhombic single phase. Photoluminescence investigations of CdNb2O6 samples showed a strong blue emission band centered at 460 nm. For Eu-doped CdNb2O6 samples, the luminescence of Eu(3+) was observed with the host red emission varying with the Eu-doping concentrations. This PL characteristic of the doped samples may be attributed to the energy transfer between Eu(3+) and niobate groups (NbO6). Boron incorporation has remarkably increased the luminescence of Eu(3+)-doped CdNb2O6.
