Photoluminescence Investigations of the Near White Light Emitting Perovskite Ceramic SrZrO_3: Dy~(3+) Prepared Via Gel-Combustion Route

摘要

Trivalent dysprosium-doped strontium zirconate perovskite (SrZrO_3) phosphors were prepared by gel-combustion synthesis using citric acid as fuel and ammonium nitrate as oxidizer. X-ray diffraction patterns confirmed the formation of orthorhombic phase of SrZrO_3 with minor impurity, which completely disappears at high temperature. The morphological investigation was carried out using scanning electron microscopy (SEM). Photoluminescence studies showed that no emission from the host is observed, indicating the efficient energy transfer from the ZrO_3~(2-) group to Dy~(3+) ions. The emission line is purely because of f-f transitions of Dy~(3+). Moreover, these phosphors predominantly exhibit near white light emission, when excited by 229 nm UV light due to strong ~4F_(9/2)→~6H_(13/2) transition at 577 nm (yellow), strong ~4F_(9/2)→~6H_(15/2) transition at 482 nm (blue), and weak ~4F_(9/2)→~6H_(9/2) transition at 677 nm (red). Enhancement in emission intensity was observed with increase in the annealing temperature of the phosphor. The CIE chromaticity coordinates of the SrZrO_3:Dy~(3+) phosphors were observed to fall in the white light domain of the chromaticity diagram, which indicate that such fine tuning might be possible after varying the temperature of annealing.