Synthesis, characterization and photoluminescence properties of CaSiO(3) : Dy(3+) nanophosphors

CaSiO(3) : Dy(3+) (1-5 mol. %) nanophosphors were synthesized by a simple low-temperature solution combustion method. Powder X-ray diffraction patterns revealed that the phosphors are crystalline and can be indexed to a monoclinic phase. Scanning electron micrographs exhibited faceted plates and angular crystals of different sizes with a porous nature. Photoluminescence properties of the Dy(3+)-doped CaSiO(3) phosphors were observed and analyzed. Emission peaks at 483, 573 and 610 nm corresponding to Dy(3+) were assigned as (4)F(9/2)->(6)H(15/2), (4)F(9/2) -> (6)H(13/2) and (4)F(9/2) -> (6)H(11/2) transitions, respectively, and dominated by the Dy(3+) (4)F(9/2) -> (6)H(13/2) hyperfine transition. Experimental results revealed that the luminescence intensity was affected by both heat treatment and the concentration of Dy(3+) (1-5 mol. %) in the CaSiO(3) host. Optimal luminescence conditions were achieved when the concentration of Dy(3+) was 2 mol. %. UV-visible absorption features an intense band at 240 nm, which corresponds to an O-Si ligand-to-metal charge transfer band in the SiO(3)(2-) group. The optical energy band gap for the undoped sample was found to be 5.45 eV, whereas in Dy(3+)-doped phosphors it varies in the range 5.49-5.65 eV. The optical energy gap widens with increase of Dy(3+) ion dopant