Recent studies are developing small energy-harvesting devices that can make them applicable in wearable medical devices and sensors. Previous attempts have been made to construct solar cells that could be incorporated into textiles, but these were challenged by long-term stability in air and water, energy efficiency, and resistance to deformation.
A new design of solar cell has been developed offering sleekness, flexibility, elasticity, and more importantly, great environmental stability, efficiency, and mechanical strength. The scientists from RIKEN and University of Tokyo fabricated this superior solar cell out of a polymeric material called PNTz4T.
This was then deposited on a parylene film, another polymeric material that has excellent resistance to water, gas, and chemical damages.
The resulting sandwich was then coated on both sides with an acrylic-based elastic polymer or elastomer, which also prevents water infiltration while allowing light to pass through the PNTz4T.
The resulting solar cell package has an energy efficiency of 7.9 percent and produces a current of 7.86 milliwatts per square centimeter. Environmental stability and mechanical strength tests showed encouraging results. Soaking it in water for two hours, the efficiency decreased only by 5.4 percent. Compressing it for twenty cycles with water drops on it, the efficiency decreased by 20 percent.