Encapsulation of pentacene/C60 organic solar cells with Al2O3 deposited by atomic layer deposition

Organic solar cells based on pentacene/C-60 heterojunctions were encapsulated using a 200-nm-thick film of Al2O3 deposited by atomic layer deposition (ALD). Encapsulated devices maintained power conversion efficiency after exposure to ambient atmosphere for over 6000 h, while devices with no encapsulation degraded rapidly after only 10 h of air exposure. In addition, thermal annealing associated with the ALD deposition is shown to improve the open-circuit voltage and power conversion efficiency of the solar cells. (c) 2007 American Institute of Physics.