Synthesis and hybridization of CuInS₂ nanocrystals for emerging applications

Copper indium sulfide (CuInS₂) is a ternary A^(I)B^(III)X(VI)2-type semiconductor featuring a direct bandgap with a high absorption coefficient. In attempts to explore their practical applications, nanoscale CuInS₂ has been synthesized with crystal sizes down to the quantum confinement regime. The merits of CuInS₂ nanocrystals (NCs) include wide emission tunability, a large Stokes shift, long decay time, and eco-friendliness, making them promising candidates in photoelectronics and photovoltaics. Over the past two decades, advances in wet-chemistry synthesis have achieved rational control over cation-anion reactivity during the preparation of colloidal CuInS₂ NCs and post-synthesis cation exchange. The precise nano-synthesis coupled with a series of hybridization strategies has given birth to a library of CuInS₂ NCs with highly customizable photophysical properties. This review article focuses on the recent development of CuInS₂ NCs enabled by advanced synthetic and hybridization techniques. We show that the state-of-the-art CuInS₂ NCs play significant roles in optoelectronic and biomedical applications.