FLUORESCENCE-SPECTRA OF EU3+LN(2)O(2)S (LN=Y,LA,GD) POWDER PHOSPHORS

This paper reports the preparation and analysis of the photoluminescen ce spectra of Eu3+-doped lanthanide oxysulfide [Y2O2S, La2O2S, and Gd2 O2 S] powder phosphors. These phosphors have displayed bright red colo r under a UV source. The richness of the red color has been verified b y determining their color coordinates ((X) over bar,(Y) over bar) from the CIE standard charts, and this red emission has been assigned to t he transition [D-5(0) --> F-7(2)] at 625 nm. Besides this stronger emi ssion transition, four weaker fluorescent transitions have been observ ed, and for these the relative fluorescence intensity ratios (R) have been determined.