Scientists in South Korea have made ultra-thin photovoltaics (solar panels) that are flexible enough to wrap around a standard pencil. Thin materials flex more easily than their thick counterparts because the stress in the materials as it is being bent increases farther out from the central plain. Thicker objects thus have more material farther out making it harder to bend. This new technology allows for the photovoltaic to be about 1 micrometer thick which is much thinner than the average human hair! Standard photovoltaic cells are hundreds of times bigger and most other this cells are two to four times bigger.
By using a printing method the scientists created a direct metal to metal bond using stamping, cold welding, and high pressure at 170 degrees celcius. The process avoided adhesives that would add to the the size and allowed for compacting the material into this incredibly thin size. The scientists found that the bottom layer of the metal in the cell also served as a reflector to direct stray photons back into the solar cells. Solar cells 1 micrometer in thickness have been created before, but have used an etching method instead of the printing method South Korean scientists used which requires less material.
These thin cells can flex and be used in wearable electronics like fitness trackers, smart glasses, and smart watches. The practical uses for flexible mini solar cells have endless possibilities and can become a great source for energy in many forms down the line! Possibly a cell phone case that can charge your phone? What other uses can you think of for this amazing technological discovery?