Japanese organic solar cell survives a washing machine test

The cell is 3 micrometers thick, bends and might be the key to making solar clothes.

Researchers from Japan’s Riken Center for Emergent Matter Science have developed a waterproof and flexible organic solar cell with a 14.3% efficiency. At just 3 micrometers thick, it is the first of its kind to survive a washing machine cycle while retaining its efficiency.

The team created this cell using a special method to improve the adhesion between layers. They grew a hole-transporting layer on the active layer and anode, then deposited a silver electrode and subjected it to heat treatment at 85 degrees Celsius for 24 hours. This process enhanced the waterproofness and flexibility of the cell.

Under one sun illumination, the cell achieved a champion efficiency of 14.3%. It retained 89% of its initial performance after being submerged in water for four hours and maintained 96% performance after being stretched underwater by 30% for 300 cycles. Impressively, the cell also survived two washing machine cycles, with only a 10% efficiency loss.

Kenjiro Fukuda, one of the lead researchers, mentioned that this method could be widely applied. The team aims to improve the stability of these cells against air, strong light, and mechanical stress, making them suitable for practical wearable devices.

The research findings are published in "Nature Communications" under the title “Waterproof and ultraflexible organic photovoltaics with improved interface adhesion.”