Fill-factor and performance optimization in bulk-heterojunction organic solar cells

One important key to improve the bulk-heterojunction photovoltaics (BHJs) is the fill-factor (FF). In this work, a study of the FF dependence factors on BHJs with an active layer of MEH-PPV / PCBM is made. The FF changes from 20% to 70%, depending on the current – voltage behavior and on the photovoltaic equivalent circuit parameters changes (parallel and series resistances, voltage open circuit, short circuit current and photocurrent). The efficiency changes from 1% to 5%. A theoretical simulation for FF optimization is made allowing a better understand of the physical process involved in the BHJ that modulates such parameter.