Fossil fuels such as coal, oil, and gas have powered most of the advanced world’s infrastructure and technology for the past century. Current efforts, however, are focused on replacing these energy sources with renewable alternatives. There is a rapidly growing market for renewable, carbon neutral, energy sources, such as solar, wind or biofuels. Solar radiation is one of the most promising alternative sources of energy, mainly because there is more than enough to meet most of the world’s energy demands, but also because sunshine is relatively predictable in many parts of the world and therefore reliable. While silicon-based commercial solar cells can now reach quite high efficiencies (close to 30%), they are still too expensive because of the heavy manufacturing costs required to produce high quality silicon materials. Among the most promising, cost effective, alternatives are organic photovoltaic (OPV) devices, which can be built from inexpensive materials and simply printed as thin films onto flexible substrates. OPV Devices still suffer, however, from low efficiencies and limited lifetimes, both of which arise mainly from the difficulties in controlling and stabilizing the nanostructure within the devices. As a solution to this key problem, we are employing highly stable, self-assembled, nanowires, nanotubes, and porous networks to control the nanostructure of OPV devices thereby assuring efficient electron and hole transport within the device architecture. It is likely that a technology which has control over the nanostructure of OPV devices will lead to solar cells with high efficiencies. Since OPVs could potentially be produced at significantly lower cost, they may be able to secure a large portion of the world-wide energy market, particularly now that many governments are planning to implement carbon emission trading schemes or taxes that will make renewable energy sources more competitive with fossil fuel power generation.