DOPING EFFECT OF VIOLOGEN ON PHOTOCONDUCTIVE DEVICE MADE OF POLY (P-PHENYLENEVINYLENE)

We report the photovoltaic properties of the donor-acceptor composite system of poly (p-phenylenevinylene) (PPV) and viologen. We observed t he significant enhancement of photocurrent with increasing the doping ratio of viologen. The maximum photocurrent of viologen-doped PPV was nine times as high as that of the pristine PPV. The maximum quantum yi eld and photosensitivity are 13% (electron/photon) and 0.05 A/W, respe ctively, at low bias voltage (-2 V). The increase of photocurrent is e xplained with the efficient charge separation that resulted from the t ransfer of photoexcited electrons from PPV to viologen. The mixture of PPV and viologen can be used as a sensitive photodiode material. (C) 1998 American Institute of Physics.