title: Solution-processed pH-neutral conjugated polyelectrolyte improves interfacial contact in organic solar cells.
abstract: The intrinsic acidic nature of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-transporting layer (HTL) induces interfacial protonation and limits the device performance in organic solar cells based on basic pyridylthiadiazole units. By utilizing a pH neutral, water/alcohol soluble conjugated polyelectrolyte CPE-K as the HTL in p-DTS(PTTh2)2:PC71BM solar cells, a 60% enhancement in PCE has been obtained with an increased V(bi), reduced R(s), and improved charge extraction. These effects originate from the elimination of interfacial protonation and energy barrier compared with the PEDOT:PSS HTL.
authors.affiliation: Center for Polymers and Organic Solids, University of California, Santa Barbara , Santa Barbara, California 93106, United States.
authors.forename: Huiqiong
authors.initials: H
authors.lastname: Zhou
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Cheng-Kang
authors.initials: CK
authors.lastname: Mai
authors.forename: Jason
authors.initials: J
authors.lastname: Seifter
authors.forename: Thuc-Quyen
authors.initials: TQ
authors.lastname: Nguyen
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Heeger
keywords: bulk heterojunctions; hole-transporting layers; interface engineering; interfacial interaction; organic solar cells