title: A molecular nematic liquid crystalline material for high-performance organic photovoltaics.
abstract: Solution-processed organic photovoltaic cells (OPVs) hold great promise to enable roll-to-roll printing of environmentally friendly, mechanically flexible and cost-effective photovoltaic devices. Nevertheless, many high-performing systems show best power conversion efficiencies (PCEs) with a thin active layer (thickness is ~100 nm) that is difficult to translate to roll-to-roll processing with high reproducibility. Here we report a new molecular donor, benzodithiophene terthiophene rhodanine (BTR), which exhibits good processability, nematic liquid crystalline behaviour and excellent optoelectronic properties. A maximum PCE of 9.3% is achieved under AM 1.5G solar irradiation, with fill factor reaching 77%, rarely achieved in solution-processed OPVs. Particularly promising is the fact that BTR-based devices with active layer thicknesses up to 400 nm can still afford high fill factor of ~70% and high PCE of ~8%. Together, the results suggest, with better device architectures for longer device lifetime, BTR is an ideal candidate for mass production of OPVs.
authors.affiliation: 1] School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia [2] Department of Materials Science and Engineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117574, Singapore [3] Department of Renewable Energy, School of Power Engineering, Chongqing University, 174 Shazhengjie, Shapingba, Chongqing 400044, China.
authors.forename: Kuan
authors.initials: K
authors.lastname: Sun
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: Zeyun
authors.initials: Z
authors.lastname: Xiao
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: Shirong
authors.initials: S
authors.lastname: Lu
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zajaczkowski
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Pisula
authors.affiliation: Advanced Microscopy Facility, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: Eric
authors.initials: E
authors.lastname: Hanssen
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
authors.affiliation: MX Beamlines, Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Williamson
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: Jegadesan
authors.initials: J
authors.lastname: Subbiah
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117574, Singapore.
authors.forename: Jianyong
authors.initials: J
authors.lastname: Ouyang
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Holmes
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: Wallace W H
authors.initials: WW
authors.lastname: Wong
authors.affiliation: School of Chemistry, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Jones