Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 36: Poster III
HL 36.15: Poster
Mittwoch, 27. Februar 2008, 16:30–19:00, Poster D
Photophysics of charge transfer in polymer–C70-fullerene composites — •Björn Titze1, Andreas Sperlich1, Carsten Deibel1, Vladimir Dyakonov1,2, and Oleg Poluektov3 — 1Experimental Physics VI, Julius-Maximilians-University of Würzburg, Am Hubland, D–97074 Würzburg — 2The Bavarian Center for Applied Energy Research (ZAE Bayern), Am Hubland, D–97074 Würzburg — 3Chemistry Division Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL 60439 USA
Charge polarons in thin films of polymer and polymer–C70-fullerene composites are investigated by light induced electron spin resonance at 9,5GHz (X-Band). The materials studied were poly(3-hexylthiophene) (P3HT), [6,6] phenyl-C61-butyric acid methyl ester (PCBM) and a soluble C70-derivate. The composites show two distinct polaron signals under illumination and a temperature below 150K, which can be assigned to photogenerated polarons (P+, P−) in the blends. Furthermore, lineshapes and relaxation times have been studied by 130GHz (D-Band) electron spin echo below 30K. The g-tensors of positive polarons (P+) on P3HT and negative polarons (P−) on C70 have been determined. The T1-relaxation time for both spectra is followed by the interaction of the polarons. We discuss the results with regard to applications such as organic bulk heterojunction solar cells.