Y3Al5O12:Re3+ (Re=Ce, Eu, and Sm) Nanocrystalline Powders Prepared by Modified Glycine Combustion Method

Abstract

Yttrium aluminum garnet doped with rare earth ions (Ce3+, Eu3+ and Sm3+) was prepared by modified glycine method. Ce3+ as a dopant was used in four different concentrations (Y3-xCexAl5O12; x(%) = 1, 2, 3, 5), while doping concentration of Eu3+ and Sm3+ was Y3-xEuxAl5O12; x(%) = 3 and Y3-xSmxAl5O12; x(%) = 1, respectively. Phase composition of powders was investigated using XRD technique and expected target phase was confirmed. Photoluminescent characterization included measurements of excitation and emission spectra, as well as determination of emission decays. Y3-xCexAl5O12 shows intense broad-band emission, with maximum in green spectral region, at about 524 nm under ultraviolet or blue excitation. The origin of the luminescence is the 5d(1)- GT 4f(1) transition which is both parity and spin allowed. Ultraviolet and blue excitations of Eu3+ and Sm3+ doped Y3Al5O12 produce intense orange and red emissions. These emissions are phosphorescent in character and come from spin forbidden f-f electron transitions in Eu3+ and Sm3+ ions. For the case of Eu3+ doping emission comes mainly from D-5(0)- GT F-7(1) transitions with Stark components peaking at 590 nm and 590.75 nm, and with emission decay of 4.15 ms. In the case of Sm3+ doping, the emission spectrum, shows (4)G(5/2)- GT H-6(5/2), (4)G(5/2)- GT H-6(7/2), and (4)G(5/2)- GT H-6(9/2) transitions, with the most intense stark components positioned at 567.5 nm, 617 nm, and 650 nm, respectively and for transition centered at 617 nm, emission decay is 3.12 ms.