Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 72: Poster Session: Si-based Photovoltaics / Inorganic Photovoltaics / Structure and Transport in Organic Photovoltaics / Organic Semiconductors

HL 72.22: Poster

Wednesday, March 28, 2012, 16:00–19:00, Poster D

Recombination of excited species in organic photovoltaic material systems studied by field dependend transient absorption — •Clemens Grünewald¹, Julia Kern¹, Julien Gorenflot¹, Carsten Deibel¹, and Vladimir Dyakonov^1,2 — ¹Experimental Physics VI, Julius Maximilian University of Würzburg, D-97074 Würzburg — ²ZAE Bayern, D-97074 Würzburg

Organic opto-electronic devices such as bulk heterojunction solar cells are limited in their efficiency due to intrinsic geminate and non-geminate charge carrier losses. The recombination dynamics of the latter mechanism are observed with time resolved photoinduced absorption spectroscopy from submicro- to milliseconds at different temperatures and wavelengths to address polarons. Starting with the well-probed poly(3-hexylthiophene) : [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) material system the study also covers promising donor polymers such as PTB7. In addition an external electric field is applied to these organic blends in order to address charge carrier generation and recombination behaviour under bias. The dependence of the photogeneration of free charge carrier on electric field and temperature are described in relation to the Braun-Onsager model.