Preparation and characterization of CuInS2nanocrystals for photovoltaic materials

Abstract

Copper indium disulphide (CIS) nanocrystals (NCs) were prepared using a one-pot synthesis. The stoichiometry was optimized based on its current density as measured by photoelectrochemical (PEC) experiments at interfaces between NC films deposited on ITO and 0.1 M methyl viologen dichloride (MV²⁺) solution. This method also offers insight into the kinetics of the photoreaction. A copper poor sulphur rich starting ratio was found to produce a copper-rich, indium-poor and slightly sulphur rich material. Further NC characterization was performed with SEM and TEM to investigate the morphology and crystallinity of the 30–70 nm NCs. The oxidation states of the individual elements were determined to be I, III, and 2– for Cu, In and S, respectively. Characteristics of optimal as-prepared NCs were found to be compatible among high functioning absorbing layers.