Engineers from South Korea developed very thin, flexible solar cells that can wrap around an average pencil. Photovoltaics like this could be used to power wearable electronics such as fitness trackers and similar products.
The photovoltaic cell they created is 1 micrometer thick, or just about a millionth of a meter. It is thinner than the average human hair.
The engineers from the Gwangju Institute of Science and Technology in South Korea used the semiconductor gallium arsenide. They directly stamped the cells into a flexible substrate without addition of any adhesive. It was then “cold welded” to the electrode on the substrate. Then the photoresist was removed to have direct metal to metal bond. The metal bottom also serves as a reflector for stray photons.
Tests show that it is as efficient as thicker solar cells and that it could wrap around objects with radii up to 1.4 millimeters small, and are comparably less fragile.