Investigation of photoinduced charge transfer in composites of a novel precursor PPV polymer and fullerenes

Homogenous blends of a functionalized methanofullerene, the [6,6]-Phenyl C61-butyric acid methyl ester (PCBM), with poly (p-phenylene vinylene) (PPV) made from a novel non-ionic precursor route were investigated by optical spectroscopy and by photocurrent measurements. The conversion process of the precursor polymer to the PPV in the blends with PCBM was monitored by IR absorption. In composites of PPV/PCBM strong quenching of the PPV luminescence was observed. LESR (light induced electron spin resonance) and PIA (photoinduced absorption) studies confirmed the occurrence of photoinduced electron transfer from the PPV to PCBM. Photovoltaic devices made from PPV/PCBM blends showed monochromatic power conversion efficiencies of app. 0.3%. The spectral photocurrent was observed to follow the absorption profile of the PPV.