title: Effects of solvent additive on "s-shaped" curves in solution-processed small molecule solar cells.
abstract: A novel molecular chromophore, p-SIDT(FBTThCA8)2, is introduced as an electron-donor material for bulk heterojunction (BHJ) solar cells with broad absorption and near ideal energy levels for the use in combination with common acceptor materials. It is found that films cast from chlorobenzene yield devices with strongly s-shaped current-voltage curves, drastically limiting performance. We find that addition of the common solvent additive diiodooctane, in addition to facilitating crystallization, leads to improved vertical phase separation. This yields much better performing devices, with improved curve shape, demonstrating the importance of morphology control in BHJ devices and improving the understanding of the role of solvent additives.
authors.affiliation: Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States; Institute of Physics and Astronomy, University of Potsdam, Potsdam-Golm 14476, Germany.
authors.forename: John A
authors.initials: JA
authors.lastname: Love
authors.affiliation: Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States; Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Chou
authors.affiliation: Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
authors.forename: Ye
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
authors.forename: Guilllermo C
authors.initials: GC
authors.lastname: Bazan
authors.affiliation: Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
authors.forename: Thuc-Quyen
authors.initials: TQ
authors.lastname: Nguyen
keywords: current voltage analysis; morphology; organic solar cells