Effects of Eu2+ concentration variation and Ce3+ codoping on photoluminescence properties of BaGa2S4:Eu2+ phosphor

Ba1-x-2yEuxCeyLiyGa2S4 phosphor samples were synthesized by a solid-state reaction method. The lattice parameter of the Ba1-xEuxGa2S4 phosphor samples was linearly decreased from 12.654 to 12.492 angstrom, and the main emission wavelength was shifted from 501 to 530 not with increase of the Eu2+ ion concentration (x) from 0.05 to 0.50. The relative photoluminescence (PL) intensity under 450 not excitation was increased with increase of the x from 0.05 to 0.25 due to the excitation band extended to the longer wavelength. However, when x > 0.30. the PL intensity was decreased due to nonradiative transitions among the Eu2+ ions and the formation of EuGa2S4 impurity phase. The Commission International de l'Eclairge chromaticity coordinates were also largely shifted from the bluish-green emitting region (x = 0.143, y = 0.506) to the green emitting one (y = 2.414, y= 0.658) by increasing the x from 0.05 to 0.50. The energy transfer from the Ce3+ ion to the Eu2+ ion enhanced the PL intensity of the Eu2+ ion emission under near ultraviolet and blue excitation. The PL intensity of the Ba0.900Eu0.050Ce0.025Li0.025Ga2S4 phosphor sample was higher by 24% than that of the Ba0.95Eu0.05Ga2S4 phosphor sample under 450 nm excitation. (c) 2008 The Electrochemical Society.