A versatile scheme for preparing single-phase yttrium oxysulfate phosphor

It is known that yttrium oxysulfate (Y2O2SO4) exhibits an interesting luminescent property when certain lanthanides are doped. Although there are several conventional ways of synthesizing the material, one of the main difficulties is that yttrium oxide (Y2O3) is usually obtained and remains as an impurity. The present paper describes a novel scheme that allows single-phase Y2O2SO4 to be obtained. The method is quite simple; it uses Y2O3 and carbon disulfide (CS2) as starting materials, and basically involves a combination of high-energy ball milling and heat treatment in air up to 900 deg. C. Adding an excess amount of CS2 can reduce unreacted Y2O3, enabling a single-phase powder to be obtained. The luminescence spectrum for Y2O2SO4:Eu phosphor showed a primary peak at about 619 nm when irradiated by X-rays, and the intensity was as strong as that of yttrium aluminium oxide phosphor (YAP:Ce)