Comparison of the Photovoltaic Response of Oleylamine and Inorganic Ligand-Capped CuInSe2 Nanocrystals

Thin film photovoltaic devices (PVs) were fabricated with CuInSe2 (CIS) nanocrystals capped with either oleylamine, inorganic metal chalcogenide-hydrazinium complexes (MCC), or S2-, HS-, and OH-. A CIS nanocrystal layer deposited from solvent-based inks without high temperature processing served as the active light-absorbing material in the devices. The MCC ligand-capped CIS nanocrystal PVs exhibited power conversion efficiency under AM 1.5 illumination (1.7%) comparable to the oleylamine-capped CIS nanocrystals (1.6%), but with significantly thinner absorber layers. S2--capped CIS nanocrystals could be deposited from aqueous dispersions, but exhibited lower photovoltaic performance.