Regensburg 2010 – scientific programme

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DS: Fachverband Dünne Schichten

DS 6: [HL] Organic Semiconductors: Solar Cells (Joint Session DS/CPP/HL/O)

DS 6.6: Talk

Monday, March 22, 2010, 17:15–17:30, H15

Charge Carrier Concentration and Temperature Dependent Recombination in Polymer-Fullerene Solar Cells — •Alexander Foertig¹, Andreas Baumann¹, Daniel Rauh², Thiemo Gerbich¹, Vladimir Dyakonov^1,2, and Carsten Deibel¹ — ¹Experimental Physics VI, Physical Institute, Julius-Maximilians-University of Würzburg, Am Hubland, D-97074 Würzburg — ²Centre for Applied Energy Research (ZAE Bayern e.V.), Am Hubland, D-97074 Würzburg, Germany

We performed temperature dependent transient photovoltage and photocurrent measurements on poly(3-hexyl thiophene):[6,6]-phenyl-C₆₁ butyric acid methyl ester bulk heterojunction solar cells. Thus we determined small perturbation carrier lifetime and charge carrier densities under operating conditions. We found a strongly charge carrier concentration and temperature dependent Langevin recombination prefactor. The observed recombination mechanism is discussed in terms of a bimolecular loss and compared with charge carrier extraction by linearly increasing voltage (photo-CELIV) measurements done on the same blend system. The observed charge carrier dynamics, following an apparent order larger than two, are explained by dynamic trapping of charges in the tail states of the Gaussian density of states.