A new solar cell manufacturing technology that uses a thin and uniform light-absorbing layer has been developed by Iowa State University and Ames Laboratory researchers. The thin layer is to be deposited on textured substrates and has been proved to increase the efficiency of polymer solar cells.
The material that Sumit Chaudhary and his team developed can be deposited even of ridges in the substrate measuring 1 nanometer. The result is that the light that would normally reflect in those ridges isn’t lost, but absorbed more efficiently, and reflected from one ridge to another.
“Our technology efficiently utilizes the light trapping scheme,” said Chaudhary. “And so solar cell efficiency improved by 20 percent.”
A 20 percent better conversion has been demonstrated by using the new technology on flat solar cells made from polymers. The real increase, though, is in the infrared spectrum, where they managed to squeeze as much as 100 percent more energy than a classic flat cell.
The idea of using a textured substrate is not new, but it has never been successful because nobody had found the proper coating for those nanometer-sized ridges until now. “This may be an old idea we’re using,” Chaudhary said, “but it’s never before been successfully implemented in polymer solar cells.”
“Get the substrate texture and the solution-based coating just right, “and we’re getting more power out,” said Kanwar Singh Nalwa, a graduate student in electrical and computer engineering and a student associate of the Ames Laboratory, working with Chaudhary.