title: Conjugated block copolymer photovoltaics with near 3% efficiency through microphase separation.
abstract: Organic electronic materials have the potential to impact almost every aspect of modern life including how we access information, light our homes, and power personal electronics. Nevertheless, weak intermolecular interactions and disorder at junctions of different organic materials limit the performance and stability of organic interfaces and hence the applicability of organic semiconductors to electronic devices. Here, we demonstrate control of donor-acceptor heterojunctions through microphase-separated conjugated block copolymers. When utilized as the active layer of photovoltaic cells, block copolymer-based devices demonstrate efficient photoconversion well beyond devices composed of homopolymer blends. The 3% block copolymer device efficiencies are achieved without the use of a fullerene acceptor. X-ray scattering results reveal that the remarkable performance of block copolymer solar cells is due to self-assembly into mesoscale lamellar morphologies with primarily face-on crystallite orientations. Conjugated block copolymers thus provide a pathway to enhance performance in excitonic solar cells through control of donor-acceptor interfaces.
authors.affiliation: Department of Chemical Engineering and ‡Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Changhe
authors.initials: C
authors.lastname: Guo
authors.forename: Yen-Hao
authors.initials: YH
authors.lastname: Lin
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Witman
authors.forename: Kendall A
authors.initials: KA
authors.lastname: Smith
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.forename: Alexander
authors.initials: A
authors.lastname: Hexemer
authors.forename: Joseph
authors.initials: J
authors.lastname: Strzalka
authors.forename: Enrique D
authors.initials: ED
authors.lastname: Gomez
authors.forename: Rafael
authors.initials: R
authors.lastname: Verduzco