title: Continuous Flow Polymer Synthesis toward Reproducible Large-Scale Production for Efficient Bulk Heterojunction Organic Solar Cells.
abstract: Organic photovoltaics (OPV) have attracted great interest as a solar cell technology with appealing mechanical, aesthetical, and economies-of-scale features. To drive OPV toward economic viability, low-cost, large-scale module production has to be realized in combination with increased top-quality material availability and minimal batch-to-batch variation. To this extent, continuous flow chemistry can serve as a powerful tool. In this contribution, a flow protocol is optimized for the high performance benzodithiophene-thienopyrroledione copolymer PBDTTPD and the material quality is probed through systematic solar-cell evaluation. A stepwise approach is adopted to turn the batch process into a reproducible and scalable continuous flow procedure. Solar cell devices fabricated using the obtained polymer batches deliver an average power conversion efficiency of 7.2 %. Upon incorporation of an ionic polythiophene-based cathodic interlayer, the photovoltaic performance could be enhanced to a maximum efficiency of 9.1 %.
authors.affiliation: Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), Hasselt University, Agoralaan 1-Gebouw D, 3590, Diepenbeek, Belgium.|IMEC, IMOMEC, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Pirotte
authors.affiliation: Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), Hasselt University, Agoralaan 1-Gebouw D, 3590, Diepenbeek, Belgium.|IMEC, IMOMEC, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.|Material Physics Division, Institute for Materials Research (IMO-IMOMEC), Hasselt University, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.
authors.forename: Jurgen
authors.initials: J
authors.lastname: Kesters
authors.affiliation: Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), Hasselt University, Agoralaan 1-Gebouw D, 3590, Diepenbeek, Belgium.|IMEC, IMOMEC, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Verstappen
authors.affiliation: Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), Hasselt University, Agoralaan 1-Gebouw D, 3590, Diepenbeek, Belgium.|IMEC, IMOMEC, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.
authors.forename: Sanne
authors.initials: S
authors.lastname: Govaerts
authors.affiliation: Material Physics Division, Institute for Materials Research (IMO-IMOMEC), Hasselt University, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.
authors.forename: Jean
authors.initials: J
authors.lastname: Manca
authors.affiliation: IMEC, IMOMEC, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.
authors.forename: Laurence
authors.initials: L
authors.lastname: Lutsen
authors.affiliation: Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), Hasselt University, Agoralaan 1-Gebouw D, 3590, Diepenbeek, Belgium.|IMEC, IMOMEC, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Vanderzande
authors.affiliation: Design & Synthesis of Organic Semiconductors (DSOS), Institute for Materials Research (IMO-IMOMEC), Hasselt University, Agoralaan 1-Gebouw D, 3590, Diepenbeek, Belgium. wouter.maes@uhasselt.be.|IMEC, IMOMEC, Universitaire Campus-Wetenschapspark 1, 3590, Diepenbeek, Belgium. wouter.maes@uhasselt.be.
authors.forename: Wouter
authors.initials: W
authors.lastname: Maes
mesh_terms: D011211:Electric Power Supplies; D011108:Polymers / Q000737:chemistry*; D012993:Solar Energy; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D011108:Polymers; D013876:Thiophenes
keywords: continuous flow synthesis; low bandgap polymers; organic semiconductors; photovoltaics; reproducible performance