Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Poster: Organic Semiconductors

CPP 24.9: Poster

Wednesday, March 28, 2012, 11:00–13:00, Poster A

Femtosecond Transient Absorption Spectroscopy of PTB7/PCBM Blend Systems — •Benjamin Müller¹, Björn Gieseking¹, Carsten Deibel¹, and Vladimir Dyakonov^1,2 — ¹Experimental Physics VI, Julius Maximilian University of Würzburg, D-97074 Würzburg — ²Bavarian Centre for Applied Energy Research (ZAE Bayern), D-97074 Würzburg

Due to their low fabrication costs bulk heterojunction organic solar cells show great potential for photovoltaic applications. The actual certified well working solar cell comprised of the copolymer PTB7 and PC₇₁BM acceptor reaches an efficiency of more than 7% reflecting the remarkable progress in this field [1]. However, recent studies indicate that the device performance strongly depends on the morphology of the active layer and is very sensitive to sample preparation [2].

In this work we investigate the influence of solvent additive on the photophysical properties of PTB7:PC₇₁BM blend films by applying picosecond timeresolved photoluminescence spectroscopy and femtosecond transient absorption spectroscopy. The experimental results are discussed in terms of the influence of the morphology on exciton diffusion and charge carrier photogeneration.

[1] Liang et al., Advanced Energy Materials 2010, 22 [2] Chen et al., Nano Letters 2011, 11, 3707-3713