title: All-polymer photovoltaic devices of poly(3-(4-n-octyl)-phenylthiophene) from Grignard Metathesis (GRIM) polymerization.
abstract: The synthesis of poly[3-(4-n-octyl)-phenylthiophene] (POPT) from Grignard Metathesis (GRIM) is reported. GRIM POPT is found to have favorable electronic, optical, and processing properties for organic photovoltaics (OPVs). Space-charge limited current and field effect transistor measurements for POPT yielded hole mobilities of 1 x 10(-4) cm(2)/(V s) and 0.05 cm(2)/(V s), respectively. Spincasting GRIM POPT from chlorobenzene yields a thin film with a 1.8 eV band gap, and PC(61)BM:POPT bulk heterojection devices provide a peak performance of 3.1%. Additionally, an efficiency of 2.0% is achieved in an all-polymer, bilayer OPV using poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-(1-cyanovinylene)phenylene] (CNPPV) as an acceptor. This state-of-the-art all-polymer device is analyzed in comparison to the analogous poly(3-hexylthiophene) (P3HT)/CNPPV device. Counter to expectations based on more favorable energy level alignment, greater active layer light absorption, and similar hole mobility, P3HT/CNPPV devices perform less well than POPT/CNPPV devices with a peak efficiency of 0.93%.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Holcombe
authors.forename: Claire H
authors.initials: CH
authors.lastname: Woo
authors.forename: David F J
authors.initials: DF
authors.lastname: Kavulak
authors.forename: Barry C
authors.initials: BC
authors.lastname: Thompson
authors.forename: Jean M J
authors.initials: JM
authors.lastname: Fréchet