A novel method for the preparation of sulfides and selenides and its application for phosphor synthesis

A new method for the synthesis of binary and tertiary sulphides and selenides from a solution of sulphur in hydrazine hydrate is described. The preparation of zinc sulphide such as SrGa2S4 is described in detail. Precipitates formed by this reaction are generally amorphous, but yield crystalline powders on further heating. Initial work has focussed on the preparation of sulphide phosphors such as ZnS:Ag. The new method has yielded phosphors with very promising characteristics, in some cases better than those made by conventional techniques (in relation to their luminescent properties). The new method does not require the elaborate precautions needed to remove the toxic gasses generated by the presently used industrial process (H2S and CS2). The new general synthetic method promises a range of possibilities for the preparation of materials with enhanced properties.