Luminescence and EPR studies of ultraviolet light emitting La_2Zr_2O_7:Gd~(3+) phosphor powder

摘要

The Gd~(3+) doped La_2Zr_2O_7 phosphor has been prepared by solution combustion method and characterized using powder X-ray diffraction, scanning electron microscopy, electron paramagnetic resonance (EPR) and photolumines-cence spectroscopy. The EPR spectrum of Gd~(3+) doped La_2Zr_2O_7 exhibits resonance signals having effective g values at g ≈ 1.84, 1.93, 2.0, 3.00, 3.85 and 6.12. Upon UV light excitation (274 nm), the phosphor exhibits a strong and sharp UV emission at 312.5 nm, which is ascribed to ~6P_(7/2) → ~8S_(7/2) transition of Gd~(3+) ions. EPR and optical investigations of the sample confirm the presence of Gd~(3+) in the La_2Zr_2O_7 matrix.