We introduce a novel nanostructuring method for bulk heterojunction solar cells which is aimed at overcoming current
limitations associated with short exciton diffusion lengths and poor charge transport. By employing a nanosphere
templating technique porous interconnected films of copper phthalocyanine (CuPc) have been prepared. Subsequent
infiltration of the CuPc structures with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) results in the formation of
three dimensionally structured nanocomposites, consisting of interpenetrating and interconnected networks. The
lengthscale separation in the composite can be engineered to match exciton diffusion lengths and the interconnectivity is
compatible with good charge transport. We propose this templating strategy as a widely applicable solution to the
continued development of low-cost organic photovoltaics.