Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 6: Electronic+Optical Properties

CPP 6.1: Talk

Monday, February 25, 2008, 14:00–14:15, C 230

Degradation mechanisms due to shading effects on organic solar cell modules — •Roland Steim^1,2, Pavel Schilinsky¹, Stelios A. Choulis^1,3, and Christoph J. Brabec⁴ — ¹Konarka Technologies GmbH, Landgrabenstrasse 94, D-90443 Nürnberg, Germany — ²Department of Electrical Engineering, University of Karlsruhe, D-76131 Karlsruhe, Germany — ³Cyprus University of Technology, Department of Mechanical Engineering & Materials Science and Engineering, 3603 Lemesos, Cyprus — ⁴Konarka Technologies, Altenbergerstrasse 69, A-4040 Linz, Austria

Organic solar cells based on Polymer:Fullerene blends have an open-circuit voltage in the range of 0.6V. Higher voltages that are needed for efficient sunlight to electrical energy conversion can be achieved by a serial connection of solar cells to modules. The voltage of each cell is added to the module voltage. The single solar cells within the module are dependent from each other and the failing of one solar cell can damage the whole module. We present data based on our investigations on module shading effects on organic solar cells. When shading one cell of a module, the shaded cell acts as load and is driven by the non-shaded ones. The shaded cell is under stress due to the applied reverse voltage and high current. Thus the shaded cell can be degraded as a function of shading time. We have investigated the failing mechanisms of reverse biased organic solar cells. We have identified, localized hot spots influence to the stability of organic solar cells under reverse bias stress. By device engineering modifications we have increased the stability of organic solar cell modules under shading.