UCLA researchers find new polymer to increase efficiency

Professor Yang Yang from UCLA has led a team of researchers at the university’s Henry Samueli School of Engineering and Applied Science in creation of a new polymer for solar cells that increases the sunlight absorption and conversion capabilities that previous polymers could not achieve.

In the 26 November issue of the Journal of the American Chemical Society, Yang and his team described how by substituting a silicon atom for a carbon atom in the backbone of the polymer, they were able to enhance the material’s PV properties. They noted that the silole-containing polymer could also be crystalline, which gives it even more potential for high-efficiency solar cells.

"With the reality of today's energy crisis, a new-game changing technology is required to make solar cells more popular," Yang said. "We hope that our newly synthesized polymer can eventually be used on solar cells far beyond their current rooftop applications. Imagine a house or car covered and powered by flexible solar films. Our dream is to see solar cells used everywhere."

Polymer solar cells have been popular since they use organic compounds transform sunlight into electricity. On top of that they are cheaper to manufacture than the silicon-based solar cells, while being environmentally friendly. Unfortunately, polymer solar cells have had quite a low efficiency rate, regardless of their longevity in the industry. However, Yang’s new polymer reached 5.1% efficiency when the results were published in the study and has improved to 5.6% in the lab during the last few months.

"Previously, the synthesizing process for the polymer was very complicated. We've been able to simplify the process and make it much easier to mass produce," said Jianhui Hou, UCLA postdoctoral researcher and co-author of the study. "Though this is a milestone achievement, we will continue to work on improving the materials. Ideally we'd like to push the performance of the solar cell to higher than 10 percent efficiency. We know the potential is there."

Solarmer Energy, Inc. and UC Discovery Grant funded the study with Solarmer licensing the technology from UCLA for commercialization.