title: Controlling molecular weight of a high efficiency donor-acceptor conjugated polymer and understanding its significant impact on photovoltaic properties.
abstract: The molecular weight (MW) of PBnDT-FTAZ can be precisely controlled by adjusting the stoichiometric ratio of the two monomers, following the Carothers equation. The study of a set of PBnDT-FTAZ polymers with different MWs reveals that the MW significantly influences the morphology and structural order of PBnDTFTAZ in its bulk heterojunction solar cells, with the highest efficiency (over 7%) achieved with the use of a MW of 40 000 g mol(-1) .
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA.
authors.forename: Wentao
authors.initials: W
authors.lastname: Li
authors.forename: Liqiang
authors.initials: L
authors.lastname: Yang
authors.forename: John R
authors.initials: JR
authors.lastname: Tumbleston
authors.forename: Liang
authors.initials: L
authors.lastname: Yan
authors.forename: Harald
authors.initials: H
authors.lastname: Ade
authors.forename: Wei
authors.initials: W
authors.lastname: You
keywords: GIWAXS; R-SoSX; miscibility; mixed domains; molecular weight; polymer solar cells; soft X-ray scattering