Improving the efficiency of plastic-based solar cells

Researchers from Victoria University of Wellington are helping to improve the efficiency of next-generation solar cells made from materials like plastics. Their work has been published in the Journal of the American Chemical Society.

The research addresses the long-standing question of how light produces charge pairs far enough apart from each other that they are free to flow as current, rather than staying bound together and ultimately just releasing heat. The researchers froze the solar cells to -263°C, where charge pairs get stuck together, then used lasers to measure how far apart they moved as the temperatures increase.

“We found that the efficiency of a polymer, or plastic-based, solar cell is determined by the ability of charge pairs to rapidly escape from each other while they are still ‘hot’ from the light energy,” said Dr Hodgkiss.

He added that understanding how plastic solar cells work will result in more efficient and cheaper conductive materials that overcome the limitations of conventional solar cells, stating, “Because they’re plastic and flexible, they could be rolled out to cover a tent or used as semi-transparent filters on windows.”

The findings of the research settles a long-standing debate about how polymer solar cells work. It also offers the potential to guide the design of cheaper and more efficient materials by isolating the key step in their development.