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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: Organic Electronics and Photovoltaics II
CPP 20.1: Vortrag
Dienstag, 23. März 2010, 13:45–14:00, H37
Spectroscopic signatures of C70-Anions in Polymer-Fullerene composites — •Andreas Sperlich1, Moritz Liedtke2, Hannes Kraus1, Oleg Poluektov4, Carsten Deibel1, Nazario Martin3, and Vladimir Dyakonov1,2 — 1Experimental Physics VI, Physical Institute, Julius-Maximilians-University of Würzburg, D-97074 Würzburg — 2ZAE Bayern, Div. Functional Materials for Energy Technology, D-97074 Würzburg — 3Departamento de Quimica Organica, Facultad de Quimica, Universidad Complutense, E-28040 Madrid — 4Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700, USA
C70-derivates are used in the most efficient organic bulk heterojunction solar cells. However, the detailed photophysical processes in composites containing C70 are still unresolved. In this contribution, our focus is on the light-induced charge transfer from the polymer to the fullerene, generating negatively charged C70 radicals. Photoinduced absorption (PIA), electron spin resonance (ESR 9.5GHz) and optically detected magnetic resonance (ODMR) were used to draw a picture of the photoinduced charge transfer from polymers to C70. We provide the first experimental identification of the light induced C70 radical anion in blends with P3HT using high frequency ESR (130GHz). Comparing spectra from C70-derivates with different sidechains, we could confirm that the electron is indeed localized on the C70-cage. Further, we identify an additional absorption band at 0.9eV due to C70− by PIA.