Enhancement of photovoltaic characteristics using a suitable solvent in hybrid polymer/multiarmed CdS nanorods solar cells

Multiarmed CdS nanorods have been used as the electron acceptors to fabricate efficient hybrid solar cells. It was demonstrated that when pyridine was used as a solvent for spin coating an active layer consisting of MEH-PPV/CdS blend instead of chlorobenzene, short-circuit current of the device can typically be increased by six times. The FTIR transmission spectrum shows that pyridine replaces the surfactant (HDA) molecules attached to the nanocrystals' surface after posttreatment of CdS nanorods by refluxing in pyridine. Transmission electron microscopy, atomic force microscopy, current-voltage characteristics, photocurrent action spectra measurements, and photoluminescence quenching were used to characterize MEH-PPV/CdS blend spin-coated from pyridine solution. Thermal treatment of the blend films can further enhance the short-circuit current in the device. Best device performance was achieved with a power conversion efficiency of 1.17% under AM1.5 illumination (100 mW cm(-2)), significantly higher than that reported so far for MEH-PPV/CdS hybrid devices.