title: A double substitution of Mg2+-Si4+/Ge4+ for Al(1)(3+)-Al(2)3+ in Ce3+-doped garnet phosphor for white LEDs.
abstract: The influence of Mg(2+)-Si(4+)/Ge(4+) incorporation into Ce(3+)-doped Y3Al5O12 garnet phosphors on the crystal structure and luminescence properties is described in this work. X-ray diffraction with Rietveld refinements, photoluminescence spectra, absolute quantum yield, thermal quenching behavior, and lifetimes were utilized to characterize samples. The introduction of Mg(2+)-Si(4+)/Ge(4+) leads to an obvious red shift of emission wavelength under the excitation of blue light, especially for the series of Mg(2+)-Si(4+) substitutions, which is suited for white light-emitting diodes (LEDs) with low color temperatures and good color rendering using only a single phosphor. More interestingly, an additional emission band locating at high-energy was observed with ultraviolet excitation, which is different than previous literature. Under the excitation of ultraviolet, the emission color for the Mg(2+)-Si(4+) substitutions can be tuned from yellow-green to blue, which is expected to obtain single-phased phosphors with white emission excited with UV-LED chip. The usual Ce(3+) emission band at low energy has stronger quenching at high temperatures. The mechanisms for the observed phenomena are discussed.
authors: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
authors: Mengmeng
authors: M
authors: Shang
authors: Jian
authors: J
authors: Fan
authors: Hongzhou
authors: H
authors: Lian
authors: Yang
authors: Y
authors: Zhang
authors: Dongling
authors: D
authors: Geng
authors: Jun
authors: J
authors: Lin