Achieving a high fill factor for organic solar cells

Organic photovoltaics (OPVs) have potential to become cost-efficient, low-energy consumption, and environmentally friendly renewable energy sources. A key parameter to determine the performance of OPVs is fill factor (FF). We review theoretical deduction as well as practical approaches to enhance FF. At present, the performance and FF of OPVs have reached above 11% and 75%, respectively.