Fabrication of ZnS nanoparticles and nanorods with cubic and hexagonal crystal structures: a simple solvothermal approach

ZnS nanoparticles and nanorods with control over their crystal structure are fabricated through a solvothermal approach by changing the solvent used for the synthesis. The synthetic approach is suitable to fabricate ZnS nanoparticles with various sizes by varying the synthesis temperatures. Quantum confinement phenomena are studied by tailoring the particle sizes for both wurtzite and sphalerite polymorphs of ZnS. Photoluminescence studies reveal that the surface states greatly influence the emissions from the nanostructures. Wurtzite nanoparticles exhibit band-edge related UV emission owing to the effective surface passivation by the ethylene glycol molecules used as the solvent for the synthesis. On the other hand, the photoluminescence spectra of the cubic nanoparticles are mainly dominated by their surface states. Some of the nanorod samples exhibited Zn-vacancy related green emissions along with the surface defect related blue emission band. It is also demonstrated that ZnS nanostructures could be easily doped with useful impurities via this synthesis approach to tailor their luminescent properties.