Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Poster: Organic Semiconductors
CPP 8.26: Poster
Montag, 14. März 2011, 17:30–19:30, P2
Water and oxygen induced degradation of small molecule organic solar cells — •Martin Hermenau1, Kion Norrman2, Frederik Krebs2, Karl Leo1, and Moritz Riede1 — 1Institut für Angewandte Photophysik, TU Dresden, George-Bähr-Str. 1, 01069 Dresden, Deutschland — 2Risø National Laboratory for Sustainable Energy, Technical University of Denmark, Roskilde, Denmark
Small molecule organic solar cells are studied with respect to water and oxygen induced degradation by mapping the spatial distribution of reaction products to elucidate the degradation patterns and failure mechanisms.
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) in conjunction with isotopic labeling using H218O and 18O2 provides information on where and to what extent the atmosphere has reacted with the device. A comparison is made between the use of a humid (oxygen free) atmosphere, a dry oxygen atmosphere, and a dry (oxygen free) nitrogen atmosphere during testing of devices that are kept in the dark and devices that are subjected to illumination. It is found that water significantly causes the device to degrade. The two most significant degradation mechanisms are diffusion of water through the aluminum electrode resulting in massive formation of aluminum oxide at the Al/BPhen interface, and diffusion of water into the ZnPc:C60 layer where ZnPc becomes oxidized. Finally, electrode diffusion is found to have no or a negligible effect on the device lifetime.