Influence of polymer solar cell geometry on series resistance and device efficiency

In order to study the influence of the organic solar cell device layout on the photovoltaic parameters, we systematically varied its geometry. By knowledge of all sheet resistances in the device, we were able to con-elate the series resistance with the geometry of the device using a simple model for its calculation. Deviations between experiment and calculation could be related with the solar cell geometry and understood by postulating curved transport ways of the current within the largely resistive ITO-layer. Thus, a further refinement of the calculation is required in order to minimize the deviation between calculation and experiment. Short solar cell lengths and ITO-bridges yield minimal series resistance and best conversion efficiency. [GRAPHICS] A schematic cross-section of a polymer solar cell displays the current flow through the device. The corresponding contributions to the series resistance are depicted as well. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim