Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 68: Photovoltaics: Organic Semiconductors

HL 68.4: Vortrag

Mittwoch, 28. März 2012, 18:30–18:45, ER 270

Field- and Temperature Dependence of charge Photogeneration in organic bulk heterojunction solar cells — •Stefan Walter¹, Markus Mingebach¹, Carsten Deibel¹, and Vladimir Dyakonov^1,2 — ¹Experimental Physics VI, Julius Maximilian University of Würzburg, D-97074 Würzburg — ²ZAE Bayern, D-97074 Würzburg

A topic of high interest is to understand the principles of charge carrier generation and recombination in organic bulk heterojunction solar cells. Generation of free charge carriers with high yield is a crucial step to ensure high power conversion efficiencies. The dissociation of singlet excitons into free charge carriers may occur either directly or via the intermediate step involving Coulomb bound charge transfer states. The field dependence of charge carrier generation can help to distinguish between these two channels. In the case of the poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61 butyric acid methyl ester (P3HT:PC60BM) blends almost no field dependence of extracted charge carrier density under positive bias between 0V and open circuit voltage was observed at room temperature [1], thus indicating a direct generation. In contrast we show a strong field dependence for poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] :[6,6]-phenyl-C61 butyric acid methyl ester (MDMO-PPV:PC60BM) blends by applying field- and temperature dependent time delayed collection field measurements.

[1] J. Kniepert, M. Schubert, J.C. Blakesley and D. Neher, J. Phys. Chem. Lett., 2, 700-705 (2011).