Influence of the Composition of Shell Layers on the Photoluminescence of Cu0.2InS2 Semiconductor Nanocrystals with a Core-shell Structure

We have synthesized core-shell structured nanocrystals based on chalcopyrite-type Cu0.2InS2. The photoluminescence of the nanocrystals shows a significant blueshift in the emission wavelength by shell capping with ZnS layers. This shift can be explained with the compressive stress to core nanocrystals applied by the formation of a ZnS shell layer with a large lattice mismatch with the core. In this study, the emission wavelength could be tuned by changing the composition of the shell layers. Nanocrystals with emission wavelength ranging from 575 nm through 630 nm were synthesized by varying the portion of cadmium compared with zinc in the shell layers.