Organic photovoltaic devices based on a block copolymer/fullerene blend

Conjugated semiconducting block copolymers are interesting organic materials for possible photovoltaic device applications because of their capability to form self-organized nanostructures and the tunability of their electronic and optical properties as a function of the relative lengths of the constituent monomers. In this work, we report the results of our investigation of polymer bulk heterojunction photovoltaic devices based on the block copolymer [MEH-PPV]-co-[biphenylene vinylene] derived from the widely used poly[2-methoxy-5-[2′-ethyl-hexyloxy]-1,4-phenylene-vinylene] (MEH-PPV) as an electron donor material in conjunction with the common electron acceptor molecule [6,6]-phenyl C61 butyric acid methyl ester, a soluble derivative of C60. We find that the morphology and photovoltaic characteristics of these devices are strongly influenced by the blend concentration and thickness of the electro-active organic layer. Our initial results demonstrate that a power conversion efficiency of 2.4% is achieved with these materials.