The pattern of information written on a Blu-ray disc, regardless of what it is, could lead to better operating solar cells. A team at Northwestern University has discovered a way to improve solar cell performance with the help of such discs. Although originally developed to optimize data compression and error tolerance, the binary codes of Blu-ray discs create a “quasi-random arrangement of islands and pits on the final media discs that are nearly optimized for photon management over the solar spectrum,” the researchers wrote in the study. The algorithms of Blu-ray standard have shown a high degree of compression by converting video signals into a sequence of 0s and 1s, with feature sizes between 150 and 525 nm. Error tolerance is increased, too, with the addition of controlled redundancy into the data sequence. “We found a random pattern or texture does work better than no pattern, but a Blu-ray disc pattern is best of all,” said professor Dr. Jiaxing Huang. The researchers tested a variety of Blu-ray movies and television shows, and found that the video content itself didn’t matter — all of the discs worked well to enhance light absorption. The overall broadband absorption enhancement of a Blu-ray-patterned solar cell was measured at 21.8 percent, according to the researchers. The pattern on the active layer of polymer solar cells was replicated, and exhibited higher efficiency than a control solar cell with a random pattern on its surface. This work could be applied to solar cells made from other materials. “In addition to improving polymer solar cells, our simulation suggests the Blu-ray patterns could be broadly applied for light trapping in other kinds of solar cells,” said professor Dr. Cheng Sun. The research was published in Nature Communications (doi: 10.1038/ncomms6517). For more information, visit www.northwestern.edu.