French government research institute CEA and Japanese fiber and textile company Toyobo have released the results of their joint research conducted over a period of 6 months since June 2019 in making trial organic PV (OPV) small cells on a glass substrate. They discovered close to 25% conversion efficiency, or 60% higher than that of amorphous silicon solar cells commonly used for desktop calculators. They claim this to be the world’s top level conversion efficiency in a dim room.

“In a verification experiment under neon lighting with 220 lux, equivalent to the brightness of a dark room, the Power-generating material for OPV OPV module on PET film substrate trial product was confirmed to have attained a conversion efficiency of about 25%, or 60 higher than that of amorphous silicon solar cells commonly used for desktop calculators,” claim the researchers.

The team was also able to have completed prototype OPV modules on a PET film substrate with an effective area of 18 cm, although coating a power-generating material on a PET film, that generated an output about 130 microwatts under the same illumination.

A Toyobo made power generating material, which it does not name, was used for the trial. This material, it claims, can dissolve in halogen-free solvants and hence can be coated evenly on a substrate.

Toyobo says it plans to propose this material mainly to solar cell makers and also use it mainly for wireless power source in devices such as temperature-humidity and motion sensors. By March 2023, it aims to have the material ready.