A novel, reproducible, and simple solution-based process for the fabrication of CuInS2 absorber layers and CdS buffer layers for photovoltaics is presented. In this process, a precursor solution is deposited on a substrate, after which sintered NCs are formed in situ at temperatures as low as 250 degrees C. Solar cell efficiencies of up to 4% have been demonstrated using this novel fabrication method.