Synthesis and characterization of CIS/CISe core–shell structured quantum dots in green systems

I–III–VI2 group compounds, such as CuInSe2 (CISe), and CuInS2 (CIS) quantum dots (QDs), are promising for photovoltaic applications by virtue of their excellent photoelectric properties and low toxicity. Considering that the surface of QDs with smaller sizes tends to have a larger density of defect states, inorganic shell layer modification is beneficial to passivate the surface defects and enhance the optical properties and quantum efficiency of QDs. In this study, a novel core–shell structure was constructed by growing a CISe shell layer with a narrower band gap on the surface of CIS nanocrystals with a wider band gap through a green and simple method. The components and properties of the core–shell QDs were analyzed by different characterization methods (XRD, TEM, EDS, UV–Vis, Raman, and fluorescence spectroscopy). The prepared CIS/CISe core–shell QDs with increased size and good coating effects exhibited high absorbance and extended carrier lifetime while showing quantum effects associated with the CISe shell layer, as well as a promising application in the field of solar cells.