THE PHOTOVOLTAIC EFFECT IN A POLY(P-PHENYLENEVINYLENE) PERYLENE HETEROJUNCTION/

We have measured the photovoltaic properties of heterojunctions consis ting of a layer of the molecular pigment bis(phenethylimido)perylene, sublimed onto a film of the conjugated polymer poly(p-phenylenevinylen e) [PPV], sandwiched between electrodes of indium tin oxide (ITO) and aluminium. Quantum yields (electrons collected per incident photon) of up to 6%, fill factors of 0.6 and open-circuit voltages approaching 1 V were obtained, representing significant improvements over single-la yer PPV devices. We interpret the photoresponse as arising from the ef ficient dissociation of electrons and holes at the PPV/perylene interf ace. Application of a simple model to the photocurrent action spectra yields an estimate of the exciton diffusion range of 90+/-10 Angstrom.