Synthesis and photoluminescence properties of Li2SO4: RE (REÂ =Â Eu3+, Tb3+, Gd3+ and Ce3+) phosphors

Li2SO4 activated with trivalent rare earth ions Eu3+, Tb3+, Gd3+ and Ce3+ were prepared by the wet chemical method which is suitable for large scale production and is an eco-friendly method. Prepared phosphors were characterized by photoluminescence technique. Photoluminescence emission spectra of Eu3+ and Tb3+ doped Li2SO4 compound shows red and green emission, respectively, under efficient n-UV (350-400 nm) excitation. This indicates that these phosphors are good and promising candidates for eco-friendly solid state lighting application. Photoluminescence of Li2SO4:Gd3+ compound shows narrow band (NB) UV-B (311 nm) emission which is in good agreement with TL-01 lamp used for treatment of psoriasis. Li2SO4 doped with Ce3+ ions possess broad emission from 300 nm to 400 nm. Electron vibrational interaction (EVI) parameters were determined for Ce3+ emission which show intermediate coupling regime. Emission spectrum of Li2SO4: Ce3+ compound matches well with emission spectrum of Sylvania broad band (UV6) lamp which is also used for phototherapy treatment.