A solar cell that makes hydrogen without a power supply Hydrogen made from water and sunlight is one of the cleanest fuels on paper, but most designs still lean on an outside electrical boost. According to a report by Interesting Engineering, a team at South Korea's Ulsan National Institute of Science and Technology (UNIST) has built an organic-semiconductor device that splits water entirely on its own, and set an efficiency record for its class while doing it. The headline number is a 7.9% sol...