Synthesis and optical properties of highly luminescent CuInS2 based core/shell nanocrystals

Copper indium sulfide (CIS) is of great interest for application in thin-film photovoltaics due to its 1.5 eV band gap. In particular, nanocrystals of CIS have received increased attention of late because of their potential amenity towards low-cost fabrication methods. I will discuss an efficient, gram-scale synthesis of this material that uses the anion precursor also as both ligand and solvent, allowing for nearly complete consumption of the more expensive cationic precursors and minimizing waste. Time-resolved spectroscopic studies show that, despite emission quantum yields as high as 10%, the as-synthesized CIS NCs show non-exponential PL dynamics. After overcoating the CIS nanocrystals with higher band gap shell materials, however, quantum yield improve by an order of magnitude and the PL decay becomes almost purely exponential, which yields important insight into the emission mechanisms in this material. Finally, I will discuss the solution-based fabrication of solar cells based on CIS nanocrystals.