Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 92: Poster Session: Structure and transport in organic photovoltaics; Photovoltaics; Impurities/Amorphous semiconductors; New materials

HL 92.4: Poster

Donnerstag, 14. März 2013, 16:00–20:00, Poster A

Influence of intercalation on geminate and nongeminate recombination in organic bulk heterojunction solar cells — •Benedikt Allendorf¹, Andreas Zusan¹, Vladimir Dyakonov^1,2, and Carsten Deibel¹ — ¹Experimental Physics VI, Julius-Maximilians-University of Würzburg, D-97074 Würzburg — ²Bavarian Centre for Applied Energy Research e.V. (ZAE Bayern), D-97074 Würzburg

The fundamental understanding of charge carrier generation and recombination is one of the key issues for further optimization of organic photovoltaics. Generation of free charge carriers with a high yield is a crucial step to ensure high power conversion efficiencies. We study how it is influenced by the morphology of the photoactive layer. We processed organic bulk heterojunction solar cells from blends of poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) with different fullerene acceptors. The blend of PBTTT donor with phenyl-C71-butyric acid methyl ester (PC₇₁BM) leads to intercalation of the acceptor molecules between the side chains of the conjugated polymers. In contrast, the bisadduct of phenyl-C61-butyric acid methyl ester (bis-PC₆₁BM) as acceptor material does not intercalate due to its larger volume. By means of time delayed collection field (TDCF) measurements we gain insight into the field dependence of polaron pair dissociation as well as into nongeminate recombination. Finally, we discuss the influence of intercalating and non–intercalating acceptors on generation and recombination of free charge carriers in organic solar cells.