2.5% efficient organic plastic solar cells

We show that the power conversion efficiency of organic photovoltaic device s based on a conjugated polymer/methanofullerene blend is dramatically affe cted by molecular morphology. By structuring the blend to be a more intimat e mixture that contains less phase segregation of methanofullerenes, and si multaneously increasing the degree of interactions between conjugated polym er chains, we have fabricated a device with a power conversion efficiency o f 2.5% under AM1.5 illumination. This is a nearly threefold enhancement ove r previously reported values for such a device, and it approaches what is n eeded for the practical use of these devices for harvesting energy from sun light. (C) 2001 American Institute of Physics.