University of Eindhoven researchers solve long-term solar cell mystery, point to more efficient process.

Researchers at Eindhoven University of Technology or TU/e in the Netherlands have come up with the answer as to why the efficiency of plastic solar cells can be doubled or tripled if a solvent is added during the production process.

The extra substance plays a comparable part to that of baking powder in a dough mixture. Exactly how this works has been unclear for the last 10 years but now the TU/e researchers have explained the mechanism in a paper published in Nature Communications, pointing to a new understanding that will enable a more focused development.

Plastic or organic solar cells use polymers instead of the usual silicon to convert the energy from sunlight into electricity. The basic material reduces the cost and weight of the cells, and makes them flexible. But their efficiency of about 10 percent still remains below that of commercial silicon counterparts, which reach between 15 and 20 percent.

About 10 years ago, a chance finding showed that the efficiency of plastic solar cells increased by a factor of two or three by including an extra solvent during the manufacturing process. “These co-solvents are now used in all plastic solar cells,” said TU/e professor René Janssen. “But nobody knew exactly why they have such a favorable effect on the efficiency.”

To read the rest of the article, please go to EETimes.