Dark and photoconductivity behavior of C60 thin films sandwiched with metal electrodes

Sandwich cells of C60 thin film with a front Al electrode reveal considerable rectifying effects and large photocurrents (quantum yields ≤54%) under air. The action spectra closely follow the optical absorption spectrum of the film. The relationship between photocurrent (Jph) and incident light intensity (Pin) changes from Jph∝(Pin)0.95±0.05 at Pin<3×10−7 W/cm2 to Jph∝(Pin)0.53±0.03 at higher Pin, suggesting that the photocurrent is controlled by the interaction of excitons with impurity sites at surface and near-surface of C60 in the absence and presence of bimolecular recombination depending on light intensity.