An ultrathin flexible organic solar cell less than 2 µm thick could have implications for the design of future flexible electronic devices. Scientists from Johannes Kepler University Linz and the University of Tokyo developed the stretchable cells – which can generate 10 W/g – based on an ultrathin polymer substrate. An ultrathin organic solar cell is so flexible that it can be used for stretchable applications. The cell pictured is glued to a prestretched elastomer. The random network of wrinkles that form upon relaxation allows for repeated stretching under continuous operation. Images courtesy of Martin Kaltenbrunner. They maintain their performance after being stretched repeatedly, displaying power conversion efficiency equal to that of their glass counterparts. They could be used in applications such as robotics, synthetic skin or e-textiles. “In all these areas, it is important that the cells are not only powerful, but also light and flexible,” said Dr. Martin Kaltenbrunner of the Institute of Experimental Physics. “[In] many things, you cannot install rigid cells.” Follow-up projects are being conducted at Johannes Kepler University. An ultrathin organic solar cell also can be used for surface-conforming electronics. The cell pictured is glued to a prestretched elastomer, biaxially compressed and then pushed out of plane by a plastic tube. “The basic system is also applicable to electrical circuits,” Kaltenbrunner said. “This is of course extremely interesting for the industry.” The research was published in Nature Communications (doi:10.1038/ncomms1772).