Photoluminescence of ZnS : Sm phosphor prepared in a reductive atmosphere

The characteristic emission of Sm+3 in Zn phosphors, fired in inert atmosph ere (N-2 gas) at various temperatures, was not detected. However, fired in reductive atmosphere at 1050 degrees C, the characteristic Sm+3 emission ap pears, which exhibits intra-4f transitions at 570, 606 and 653 nm, as predi cted from the (4)G(5/2) level to the H-6(5/2), H-6(7/2) and H-6(9/2) levels . Sm doping favors the formation of hexagonal phase in host lattice of ZnS: Sm. The increase in hexagonal phase content will boost the overall photolum inescence emission intensity. The self-activated luminescence intensity inc reases with the increase in the amount of Sm doping up to a maximum at 0.2 mol% of Sm dopant. According to the phase identification by X-ray diffracti on, the Sm2O2S phase favors the Sm+3 characteristic luminescence but it det eriorates in Sm2O3. (C) 2000 Elsevier Science Ltd and Techna S.r.l. All rig hts reserved.