Colloidal CuInS₂ quantum well nanostructures with II-VI semiconductors as barrier layers

Quantum well (QW) structures have been successfully produced and utilized in high-performance optoelectronic devices. By designing QW structures at the nanoscale, it is possible to combine the advantages of both QW structures and nanostructures, resulting in extraordinary properties. In this study, a CuInS₂ (CIS) quantum well layer was successfully constructed within a single nanostructure using a colloidal method. Various QW nanostructures were synthesized, including CdS/CIS/CdS, CdS/CIS/ZnS, ZnS/CIS/CdS, and Cd-free ZnS/CIS/ZnS configurations. The shapes of these QW nanostructures were precisely tuned to form tetrahedrons, hexagonal columns, and rods. Importantly, the morphology and crystal structure of the CIS layer play a crucial role in determining the final morphologies of the QW nanostructures. These QW nanostructures exhibit fluorescence emission in the near-infrared range (NIR), achieving a maximum quantum yield of 37% at 783 nm. This work demonstrates the successful construction of a CIS quantum well layer within a single colloidal nanoparticle, providing a valuable research model for fundamental studies and offering promising materials for optoelectronic devices.