Safe, stable and effective nanotechnology: Phase mapping of ZnS nanoparticles

Zinc sulfide (ZnS) nanoparticles are of interest for their luminescent and catalytic properties which are useful in bio-medical, electronic and photovoltaic devices. However, ZnS nanoparticles undergo reversible and irreversible phase transformations under ambient conditions, which affect the material properties and their biological and environmental significance. In this paper the current knowledge, drawn from experimental, computational and theoretical studies, is reviewed and gaps in this knowledge-base are identified. Based on this assessment, it is suggested that the development of a nanoscale phase diagram for ZnS may provide a way of rapidly assessing the complicated parameter-space occupied by this problem, and serve to highlight the size, temperature, pressure and chemical regimes that may provide the most stable and appropriate size, shape and phase for specific applications.