Facile synthesis and characterization of core/shell Cu-In-Zn-S/ZnS nanocrystals with high luminescence

Cu-Zn-In-S/ZnS (CZIS/ZnS) core/shell nanocrystals (NCs) with high quality have been successfully synthesized via a one-pot two-step method. The photoluminescent properties including emission spectra, photoluminescence quantum yield (PL QY) and PL decay time of the obtained CZIS/ZnS NCs could be tuned by controlling the growth process of ZnS shell. The effect of the amount of Zn added on the growth of ZnS shell was investigated. The shell growth temperature and time for CIZS/ZnS NCs were discussed in detail. A relatively high PL QY of 77% could be achieved under certain reaction condition after systematic study. The crystal structure, morphology, size distribution and chemical composition of CZIS/ZnS NCs were determined by X-ray Diffraction (XRD), selected-area electron diffraction (SAED), low- and high-resolution transmission spectra (TEM) and STEM-EDS, respectively. The photoluminescence mechanisms of the CZIS/ZnS NCs were discussed by time-resolved photoluminescence.