Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Poster Session 1 (joint session with BP)

CPP 19.49: Poster

Tuesday, April 1, 2014, 09:30–13:00, P1

Spatially resolved defect investigation of pinholes in metal electrodes of organic photovoltaic cells — •Daniel Fluhr, Roland Rösch, Burhan Muhsin, Marco Seeland, and Harald Hoppe — Institute of Physics, Technische Universität Ilmenau, 98693 Ilmenau, Germany

To date long operation lifetime remains a major problem of organic photovoltaic (OPV) devices, even though considerable improvements were achieved over the last few years. Among the reasons for solar cell degradation are impurity induced shunts, photobleaching of the organic semiconductors via oxygen and water as well as corrosion and delamination of the metal contacts due to the same reagents. In this study we focus on so-called pinholes occurring through the metal back electrode of typical devices. These pinholes provide pathways for the ingress of water and oxygen, which locally attack the metal organic interface, resulting in contact delamination. As charge injection and extraction is suppressed at delaminated areas, the active area taking part in power conversion is reduced and hence the overall efficiency suffers. We investigated the influence of different environmental conditions on the reduction of the active area of the OPV cell. Spatially resolved measurements provide information on location and size of inactive areas induced by pinholes in the metal back contact. Periodically applied non-invasive measurements during degradation of the devices reveal the dynamics and rate of growth of these defects. By looking at different device structures we find important conclusions for increasing the lifetime of organic photovoltaic devices.