title: Conjugated polyelectrolyte hole transport layer for inverted-type perovskite solar cells.
abstract: Organic-inorganic hybrid perovskite materials offer the potential for realization of low-cost and flexible next-generation solar cells fabricated by low-temperature solution processing. Although efficiencies of perovskite solar cells have dramatically improved up to 19% within the past 5 years, there is still considerable room for further improvement in device efficiency and stability through development of novel materials and device architectures. Here we demonstrate that inverted-type perovskite solar cells with pH-neutral and low-temperature solution-processable conjugated polyelectrolyte as the hole transport layer (instead of acidic
  PSS) exhibit a device efficiency of over 12% and improved device stability in air. As an alternative to
  PSS, this work is the first report on the use of an organic hole transport material that enables the formation of uniform perovskite films with complete surface coverage and the demonstration of efficient, stable perovskite/fullerene planar heterojunction solar cells.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Hyosung
authors.initials: H
authors.lastname: Choi
authors.affiliation: Center for Polymers and Organic Solids, University of California Santa Barbara, Santa Barbara, California 93106, USA.
authors.forename: Cheng-Kang
authors.initials: CK
authors.lastname: Mai
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea.
authors.forename: Hak-Beom
authors.initials: HB
authors.lastname: Kim
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea.
authors.forename: Jaeki
authors.initials: J
authors.lastname: Jeong
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea.
authors.forename: Seyeong
authors.initials: S
authors.lastname: Song
authors.affiliation: Center for Polymers and Organic Solids, University of California Santa Barbara, Santa Barbara, California 93106, USA.
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Center for Polymers and Organic Solids, University of California Santa Barbara, Santa Barbara, California 93106, USA.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Heeger