Organic photovoltaic cells based on conjugated polymer/fullerene composites

We fabricated organic photovoltaic cells using poly[2-methoxy,5-(2^′-ethylhexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) and fullerene derivative, [6,6]-phenylen C₆₁-butyric acid methyl ester (PCBM), composites with various concentrations of the PCBM. The devices exhibit photoluminescence quenching and enhancement in photovoltaic response with increasing PCBM concentrations, both of which are associated with the photoinduced charge transfer characteristics of these materials. We also investigate the PCBM concentration dependence on the device performance near the percolation threshold for fullerene derivative charge transport channel, and discuss the role of fullerene interpenetrating networks in these organic photovoltaic cells.