Fluorescence spectra of Eu3+:Ln(2)O(2)S (Ln=Y,La,Gd) powder phosphors

This paper reports the preparation and analysis of the photoluminescence spectra of Eu3+-doped lanthanide oxysulfide [Y2O2S, La2O2S, and Gd2O2 S] powder phosphors. These phosphors have displayed bright red color under a UV source. The richness of the red color has been verified by determining their color coordinates ((X) over bar,(Y) over bar) from the CIE standard charts, and this red emission has been assigned to the transition [D-5(0) --> F-7(2)] at 625 nm. Besides this stronger emission transition, four weaker fluorescent transitions have been observed, and for these the relative fluorescence intensity ratios (R) have been determined.