title: SOLAR CELLS. High-performance photovoltaic perovskite layers fabricated through intramolecular exchange.
abstract: The band gap of formamidinium lead iodide (FAPbI3) perovskites allows broader absorption of the solar spectrum relative to conventional methylammonium lead iodide (MAPbI3). Because the optoelectronic properties of perovskite films are closely related to film quality, deposition of dense and uniform films is crucial for fabricating high-performance perovskite solar cells (PSCs). We report an approach for depositing high-quality FAPbI3 films, involving FAPbI3 crystallization by the direct intramolecular exchange of dimethylsulfoxide (DMSO) molecules intercalated in PbI2 with formamidinium iodide. This process produces FAPbI3 films with (111)-preferred crystallographic orientation, large-grained dense microstructures, and flat surfaces without residual PbI2. Using films prepared by this technique, we fabricated FAPbI3-based PSCs with maximum power conversion efficiency greater than 20%.
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon 305-600, Korea.
authors.forename: Woon Seok
authors.initials: WS
authors.lastname: Yang
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon 305-600, Korea.
authors.forename: Jun Hong
authors.initials: JH
authors.lastname: Noh
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon 305-600, Korea.
authors.forename: Nam Joong
authors.initials: NJ
authors.lastname: Jeon
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon 305-600, Korea.
authors.forename: Young Chan
authors.initials: YC
authors.lastname: Kim
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon 305-600, Korea.
authors.forename: Seungchan
authors.initials: S
authors.lastname: Ryu
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon 305-600, Korea.
authors.forename: Jangwon
authors.initials: J
authors.lastname: Seo
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon 305-600, Korea. Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea. seoksi@krict.re.kr.
authors.forename: Sang Il
authors.initials: SI
authors.lastname: Seok