Green phosphorescence of zinc sulfide optical ceramics

In the present work, we report a novel luminescent characteristic of the ZnS ceramics. ZnS undoped nanopowders have been synthesized by a wet chemical precipitation method using Na2S as the source of sulfur. Spark plasma sintering (SPS) has been applied to the nanopowders to fabricate dense ZnS ceramics in the pure phase of zinc blende. Photoluminescence (PL) and fluorescence lifetime spectra have been utilized to characterize the luminescent properties of the ZnS ceramics, indicating that these materials exhibit green phosphorescence. In addition, elemental analysis has also been adopted to determine the elemental composition and valency of elements within the ceramic samples. It is concluded that the green phosphorescence results from the presence of elemental sulfur species and Na impurities.