What a difference one atom makes

A new study by researchers at the UCLA Henry Samueli School of Engineering and Applied Science shows exactly how important a single atom can be in a complex molecule. Reporting in the Nov.

A new study by researchers at the UCLA Henry Samueli School of Engineering and Applied Science shows exactly how important a single atom can be in a complex molecule. Reporting in the Nov. 26 edition of the Journal of the American Chemical Society, Yang Yang, a professor of materials science and engineering, and colleagues describe a new polymer, or plastic. It's being developed for solar cells and has significantly greater sunlight absorption and conversion capabilities than previously-used polymers.

The UCLA folks substituted a single silicon atom for one of the carbon atoms in the polymer's "backbone." Here's the UCLA press release summarziing the research. Polymer solar cells have been around for several years, but have been highly inefficient at converting sun to electricity. This new polymer reached 5.1 % efficiency in the published study but has in a few months improved to 5.6 % in the lab. Yang and his team have proven that the photovoltaic material they use on their solar cells is one of the most efficient based on a single-layer, low-band-gap polymer.

"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."

"We hope that solar cells will one day be as thin as paper and can be attached to the surface of your choice," added co-author Hsiang-Yu Chen, a UCLA graduate student in engineering. "We'll also be able to create different colors to match different applications."

The study was funded by Solarmer Energy Inc. and a UC Discovery Grant. Solarmer Energy Inc. has recently licensed the technology from UCLA for commercialization.

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Solarmer Energy Inc. is focused on translucent, flexible plastic solar cells. These solar cells could open the door for a wide range of new applications. It appears from their website that Solarmer is particularly eager to get into supplying polymer solar cells for numerous portable devices. Maybe even a solar car finally? Solarmer was founded in 2006 and is based in El Monte near Los Angeles.