title: The influence of polymer purification on the efficiency of poly(3-hexylthiophene):fullerene organic solar cells.
abstract: We report the influence of different polymer purification procedures on the photovoltaic performance of bulk heterojunction solar cells formed from binary blends of poly(3-hexylthiophene) (P3HT) and fullerenes. Selective Soxhlet extractions and metal scavenging agents were used to remove residual monomer, magnesium salt by-products and catalyst from high-weight P3HT (Mw 121 kg/mol, PDI 1.8, RR 99%) synthesised by the Grignard metathesis (GRIM) polymerization route. Using phenyl-C61-butyric acid methyl ester (PC60BM) as an electron acceptor, we observed an increase in average power conversion efficiency from 2.3 to 4.8% in going from crude to fully purified material. Using indene-C60 bisadduct (IC60BA) in place of PC60BM, we observed a further increase to an average value of 6.6% - high for a bulk heterojunction formed from a binary blend of P3HT and C60 fullerene derivatives.
authors.affiliation: Centre for Plastic Electronics, Imperial College London, London SW7 2AZ, UK.|Department of Chemistry, Imperial College London, London SW7 2AZ, UK.
authors.forename: James H
authors.initials: JH
authors.lastname: Bannock
authors.affiliation: Centre for Plastic Electronics, Imperial College London, London SW7 2AZ, UK.|Department of Materials, Imperial College London, London SW7 2AZ, UK.|Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California 93117, USA.
authors.forename: Neil D
authors.initials: ND
authors.lastname: Treat
authors.affiliation: Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California 93117, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Chabinyc
authors.affiliation: Centre for Plastic Electronics, Imperial College London, London SW7 2AZ, UK.|Department of Materials, Imperial College London, London SW7 2AZ, UK.
authors.forename: Natalie
authors.initials: N
authors.lastname: Stingelin
authors.affiliation: Centre for Plastic Electronics, Imperial College London, London SW7 2AZ, UK.|Department of Chemistry, Imperial College London, London SW7 2AZ, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Heeney
authors.affiliation: Centre for Plastic Electronics, Imperial College London, London SW7 2AZ, UK.|Department of Chemistry, Imperial College London, London SW7 2AZ, UK.
authors.forename: John C
authors.initials: JC
authors.lastname: de Mello