Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 62: Poster II: Photovoltaics and Organic Semiconductors

HL 62.9: Poster

Thursday, March 25, 2010, 18:00–20:00, Poster D2

Femtosecond Transient Absorption Spectroscopy of Organic Semiconductors — •Björn Gieseking¹, Daniel Kreier¹, Moritz Liedtke^1,2, Carsten Deibel¹, and Vladimir Dyakonov^1,2 — ¹Experimental Physics VI, Faculty of Physics and Astronomy, Julius-Maximilians-University Würzburg, D-97074 Würzburg — ²Bavarian Centre for Applied Energy Research (ZAE Bayern), D-97074 Würzburg

Organic solar cells based on conjugated polymers exhibit great potential for photovoltaic applications due to their low fabrication costs. Bulk heterojunction devices comprised of regioregular poly(3-hexylthiophene) and the [6,6]-phenyl-C₆₁ butyric acid methyl ester fullerene derivative have approached efficiencies of more than 5 %. A further optimization requires a deeper insight into the elementary processes following the photoexcitation of these blends. For such studies a very high time resolution is crucial.

We present investigations applying a transient absorption spectroscopy setup based on two optical parametric amplifiers which are tunable from the visible to the infrared spectral range and provide a sub picosecond time resolution. By probing the different transient species we are able to get a better understanding of photogeneration of free charge carriers and their loss mechanisms in order to improve the performance of organic solar cells.