Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 46: Organic Photovoltaics I

HL 46.9: Talk

Wednesday, March 16, 2011, 12:30–12:45, FOE Anorg

Influence of phase separation on the recombination dynamics of trapped charges in disordered organic semiconductors — •Julien Gorenflot¹, Matthias Gunz¹, Andreas Kämpgen¹, Jens Lohrmann¹, Carsten Deibel¹, and Vladimir Dyakonov^1,2 — ¹Experimental Physics VI, Julius-Maximilians University, D-97074 Würzburg — ²Bavarian Center for Applied Energy Research (ZAE Bayern), D-97074 Würzburg

Using a combination of steady-state and transient photoinduced absorption, we explore the recombination of polarons in pristine poly(3-hexylthiophene) (P3HT) as well as in its blend with [6,6]-phenyl-C61 butyric acid methyl ester(PCBM). Interestingly those two systems behave very differently with a recombination order of two for pure P3HT which contrasts with the much higher apparent order in the blend. We explain those results in terms of trap induced delay in the blend where energetically trapped polarons can be unavailable for recombination due to phase separation. We determine the activation energy of the bimolecular recombination in pure P3HT. Our results show that the polaron recombination is caused in both neat polymer and blend by intermolecular rather than intramolecular charge transport.