Efficient ultrathin organic solar cells have been produced at King Abdullah University of Science and Technology (KAUST), Saudi Arabia, by inkjet printing. The manufacturing method overcomes the constraints imposed by the more conventional use of spin-coating or thermal evaporation, which are not scalable and which limit device geometry.

Instead of using brittle indium tin oxide as an organic photovoltaic starting material, the device is assembled The inkjet-printed solar cells are light enough to sit on the surface of a soap bubble. Source: Anastasia Serin/KAUSTwith printed poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, a transparent and conductive polymer, as the cathode electrode with a zinc oxide applied as the electron transport layer. A bulk heterojunction composed of rhodanine‐endcapped indacenodithiophene nonfullerene acceptor serves as the photo‐active layer.

Printed onto glass and sealed with parylene, the 0.1 cm² soar cells achieved a power conversion efficiency of 4.73%, surpassing the previous record of 4.1% for a fully printed cell. Organic solar cells were also printed onto an ultrathin flexible parylene substrate and demonstrated a power conversion efficiency of 3.6%.

The lightweight, flexible solar cells described in Advanced Materials Technologies could be used to power small sensors, wearable electronics and other low-energy devices.