title: Hole-Transporting Materials with a Two-Dimensionally Expanded π-System around an Azulene Core for Efficient Perovskite Solar Cells.
abstract: Two-dimensionally expanded π-systems, consisting of partially oxygen-bridged triarylamine skeletons that are connected to an azulene (1-3) or biphenyl core (4), were synthesized and characterized. When tetra-substituted azulene 1 was used as a hole-transporting material (HTM) in perovskite solar cells, the observed performance (power conversion efficiency = 16.5%) was found to be superior to that of the current HTM standard Spiro-OMeTAD. A comparison of the hole mobility, the ability to control the HOMO and LUMO levels, and the hole-collection efficiency at the perovskite/HTM interface in 1 with reference compounds (2-4 and Spiro-OMeTAD) led to the elucidation of key factors required for HTMs to act efficiently in perovskite solar cells.
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Nishimura
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University , 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishida
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Shimazaki
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.|Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency , 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Wakamiya
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University , 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Saeki
authors.affiliation: Merkert Chemistry Center, Boston College , Chestnut Hill, Massachusetts 02467-3860, United States.
authors.forename: Lawrence T
authors.initials: LT
authors.lastname: Scott
authors.affiliation: Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Yasujiro
authors.initials: Y
authors.lastname: Murata