In this cross-section of an organic photovoltaic cell, light passes through the upper layers (from top down, glass, indium tin dioxide, and thermoplastic) and generates a photocurrent in the polymer-fullerene layer. Channels formed by polymers (tan) and fullerenes (dark blue) allow electric current to flow into the electrode at bottom. NIST research has revealed new information about how the channels form, potentially improving cell performance.
 A new class of economically viable solar power cells—cheap, flexible and easy to make—has come a step closer to reality as a result of recent work* at the National Institute of Standards and Technology (NIST), where scientists have deepened their understanding of the complex organic films at the heart of the devices.

Organic photovoltaic, which rely on organic molecules to capture sunlight and convert it into electricity, are a hot research area because in principle they have significant advantages over traditional rigid silicon cells. Organic photovoltaic start out as a kind of ink that can be applied to flexible surfaces to create solar cell modules that can be spread over large areas as easily as unrolling a carpet.

They’d be much cheaper to make and easier to adapt to a wide variety of power applications, but their market share will be limited until the technology improves. Even the best organic photovoltaic s convert less than 6 percent of light into electricity and last only a few thousand hours. “The industry believes that if these cells can exceed 10 percent efficiency and 10,000 hours of life, technology adoption will really accelerate,” says NIST’s David Germack. “But to improve them, there is critical need to identify what’s happening in the material, and at this point, we’re only at the beginning.”