Researchers have built a new kind of two-faced (bifacial) panel. They used single-walled carbon nanotubes as both front and back electrodes. These tubes are just 2.2 nanometers across. That is slightly thinner than a strand of human DNA. A piece of paper is thicker than 45,000 nanotubes stacked on top of each other.
The study is published in the journal Nature Communications, and the team included Surrey scientists working with colleagues at the University of Cambridge, the Chinese Academy of Sciences, Xidian University, and Zhengzhou University, China.
The bifacial cells can harvest sunlight from both front and back panels. This generates more energy and depends less on which angle the light hits them. The carbon nanotubes are very transparent and conduct electricity well and they have the potential to bring clean power within reach for millions of people.
The panels can generate more than 36 mW per square centimeter—and the back panel produced nearly 97% of the power that the front panel did. That compares to 75%–95% for most bifacial panels currently on the market.
The world cannot decarbonize without solar power. Yet that requires much cheaper solar energy than is currently available. Panels that can absorb the sun’s energy on both sides are a great way to make the technology more cost-effective. These panels cost 70% less to make than a normal one-sided solar panel. This could significantly modify the market and simplify the architectures required based on perovskite solar cells.