Photoinduced C70 radical anions in polymer:fullerene blends |
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| Authors: | Andreas Sperlich Moritz Liedtke Julia Kern Hannes Kraus Carsten Deibel Salvatore Filippone Juan Luis Delgado Nazario Martín Vladimir Dyakonov |
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| Institution: | 1. Experimental Physics VI, Julius‐Maximilians University of Würzburg, 97074 Würzburg, Germany;2. Bavarian Center for Applied Energy Research (ZAE Bayern), 97074 Würzburg, Germany;3. Departamento de Química Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain;4. IMDEA‐Nanociencia, Facultad de Ciencias, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain |
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| Abstract: | Photoinduced polarons in solid films of polymer:fullerene blends were studied by photoluminescence (PL), photoinduced absorption (PIA) and electron spin resonance (ESR). The donor materials used were P3HT and MEH‐PPV. As acceptors we employed PC60BM as reference and various soluble C70‐derivates: PC70BM, two different diphenylmethano‐70]fullerene oligoether (C70‐DPM‐OE) and two dimers, C70–C70 and C60–C70. Blend films containing C70 revealed characteristic spectroscopic signatures not seen with C60. Light‐induced ESR showed signals at g ≥ 2.005, assigned to an electron localized on the C70 cage. The formation of C70 radical anions also leads to a subgap PIA band at 0.92 eV, hidden in the spectra of C70‐based P3HT and MEH‐PPV blends, which allows for more exact studies of charge separated states in conjugated polymer:C70 blends. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) |
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| Keywords: | electron spin resonance photoinduced absorption fullerenes C70 carbon organic solar cells |
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