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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 5: Poster
SYOH 5.45: Poster
Donnerstag, 11. März 2004, 18:00–21:00, B
Optical and Electronic Contributions in Thin Film Organic Solar Cells — •Helmut Hänsel1, Heiko Zettl1, Georg Krausch1, Roman Kisselev2, Mukundan Thelakkat2, and Hans-Werner Schmidt2 — 1Universität Bayreuth, Physikalische Chemie II — 2Universität Bayreuth, Makromolekulare Chemie I,D-95447 Bayreuth
We investigate the photocurrent of a (ITO/CuPc/perylene dye/Al) cell and a (ITO/CuPc/perylene dye/TiO2/Al) cell as a function of the perylene dye layer thickness. In addition to the experimental data, we present a model that describes the short circuit current of these cells. The charge generation probability is estimated from the intensity profile that is calculated via a matrix transfer algorithm taking into account the full illumination spectrum. We find that the TiO2 layer modifies the short circuit current by two effects: Optically, by shifting the charge transfer interface with respect to the light intensity profile, and electronically, by introducing a second heterojunction where additional charge transfer can occur. Thickness dependent studies can clearly separate these two effects and can yield an estimate of the ratio of the exciton diffusion lengths in the absorbing media. The high accuracy in thickness variation that is necessary for such study is achieved by the combinatorial fabrication and testing of the devices. We can furthermore show that the introduction of the TiO2 layer leads to a faster and stronger degradation.