Dresden 2009 – wissenschaftliches Programm

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SYOP: Symposium Organic Photovoltaics: From Single Molecules to Devices

SYOP 4: Organic Photovoltaics: from Single Molecules to Devices

SYOP 4.33: Poster

Donnerstag, 26. März 2009, 16:30–19:00, P1A

Bipolar Charge Transport in Poly(3-hexylthiophene)/ Methanofullerene Blends: A Ratio Dependent Study — •Andreas Baumann¹, Jens Lorrmann¹, Carsten Deibel¹, and Vladimir Dyakonov^1,2 — ¹Julius-Maximilians-University of Würzburg, Institute of Physics, Experimental Physics VI, D-97074 Würzburg — ²Bavarian Centre for Applied Energy Research e.V. (ZAE Bayern), D-97074 Würzburg

One of the most promising candidates for bulk heterojunction (BHJ) solar cells nowadays is the material combination of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C₆₁ butyric acid methyl ester (PCBM). One of the prerequisites for a well-performing BHJ solar cell is that the respective mobilities for transporting electrons on the fullerene and holes on the polymer are rather balanced, in order to avoid a space charge building up. We investigated the charge carrier mobility in P3HT:PCBM blend devices by applying the time resolved photoconductivity experiment as a function of the donor:acceptor ratio. We observed bipolar transport in all studied samples ranging from pure polymer to polymer:fullerene with 90% PCBM content. Furthermore, two transit times in the hole and electron current transients were found [1]. We discuss their origin in terms of electron (hole) transport on P3HT (PCBM), respectively and simulate the hopping transport by using Monte Carlo simulation.

[1] Baumann et al., accepted for publication in Appl. Phys. Lett.