Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Poster Session 1 (joint session with BP)

CPP 19.27: Poster

Tuesday, April 1, 2014, 09:30–13:00, P1

Trap-assisted recombination in PCDTBT:PC₇₁BM blend films investigated by transient absorption — •Jeremias Weinrich¹, Andreas Fritze¹, Vladimir Dyakonov^1,2, and Carsten Deibel¹ — ¹Experimental Physics VI, Julius-Maximilian University of Würzburg, D-97074 Würzburg — ²Bavarian Centre for Applied Energy Research (ZAE Bayern e.V.), D-97074 Würzburg

Organic photovoltaic cells have the potential to be a key technology in the field of renewable energies. They are comparatively cheap and compatible to mass production, yet have a lower power conversion efficiency (PCE) compared to silicon solar cells. The low-bandgap polymer PCDTBT, blended with PC₇₁BM as acceptor, is a promising electron donor in organic bulk heterojunction solar cells, with PCE’s yielding above 6 %.
Charge carrier recombination is the dominant loss mechanism in these devices, reducing the number of charge carriers before extraction at the electrodes. We performed transient absorption spectroscopy to probe the laser-pulse induced charge carrier concentration and its decay on a time scale of 10 ns to 1 ms at different pump intensities and temperatures. We discuss the charge carrier dynamics and activation energies as well as the origin of nongeminate losses in PCDTBT-based solar cells.