Science Energy Waterproof Solar Cell Could Go Through the Wash and Still Work By Megan Treacy Writer University of South Carolina Megan Treacy is a freelance writer from Austin, TX. A former editor at EcoGeek, she worked as a technology columnist for Treehugger from 2012 to 2018. our editorial process Megan Treacy Updated October 11, 2018 ©. RIKEN Share Twitter Pinterest Email Energy Renewable Energy Fossil Fuels A new type of ultra-thin solar cell could make it through laundry day without any negative effects. Developed by Japanese company RIKEN and the University of Tokyo, the solar cell is coated on both sides with a waterproof covering allowing it to keep generating electricity from sunlight even after being soaked in water. The flexible solar cell can also be bent, stretched and compressed and keep working. The new technology could pave the way for wearable photovoltaics that can be embedded in clothing to power health monitors or medical devices and thrown in with the wash at the end of the day. Previous attempts at making wearing photovoltaics were missing some of the key attributes of this new tech, namely stability in water and air and resistance to deformation. The thin-film cells of the past were also very low efficiency. This new solar cell was able to achieve an efficiency of 7.9 percent in testing and after soaking in water for two hours only lost 5.4 percent of its efficiency. To test its durability, the researchers put it through 20 compression and decompression cycles with the addition of drops of water and it still retained 80 percent of its efficiency. The solar cells are super thin and flexible thanks to a material called PNTz4T that the research team developed previously. The elastomer coating on both sides serves to keep water and air out, but allows light to enter. The use of this type of solar cells in textiles could make wearable devices and their power source much more seamless and the ruggedness of the cell could help it to find its way in even more applications that require a solar cell to withstand the elements.