Origin of photocurrent generation and collection losses in large area organic solar cells

Loss of performance in large area devices is a major concern for organic solar cells. We present studies highlighting up-scaling loss mechanisms caused by interfacial resistance at organic-metal interface in pentacene/C-60 heterojunction solar cells. Devices with different active areas and electrodes are investigated, revealing the origin of higher series resistance in large area devices. We also simulate influence of spatial non-uniformity and anisotropic charge collection in active layer through selective coverage using customized electrode geometries and identify grain boundaries as the dominating link behind loss in photocurrent generation and collection. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3637041]