Novel Reddish-Orange-Emitting BaLa2Si2S8:Eu2+ Thiosilicate Phosphor for LED Lighting

Abstract

A novel reddish-orange-emitting BaLa2Si2S8:Eu2+ thiosilicate was prepared in a sealed fused silica ampule and its crystal structure was refined using Rietveld methods. The BaLa2Si2S8:Eu2+ phosphor is excitable over a broad range from UV to blue (350-450 nm) and generated a reddish-orange broadband emission peaking at 645 nm with a quantum efficiency of similar to 24%. The thermal luminescence quenching of BaLa2Si2S8:Eu2+ was investigated over the range 25 to 150 degrees C. This phosphor was utilized to incorporate with two commercially available phosphors, blue BaMgAl10O17:Eu2+ and green (Ba,Sr)(2)SiO4:Eu2+, and a near-UV LED chip (405 nm), a white light with Ra of similar to 94 was obtained.