title: Nanoscale morphology of high-performance polymer solar cells.
abstract: Transmission electron microscopy and electron diffraction are used to study the changes in morphology of composite films of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) in bulk heterojunction solar cells. Thermal annealing produces and stabilizes a nanoscale interpenetrating network with crystalline order for both components. P3HT forms long, thin conducting nanowires in a rather homogeneous, nanocrystalline PCBM film. Both the improved crystalline nature of films and increased but controlled demixing between the two constitutes therein after annealing explains the considerable increase of the power conversion efficiency observed in these devices.
authors.affiliation: Group Polymer Physics, Laboratory of Materials and Interface Chemistry, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands.
authors.forename: Xiaoniu
authors.initials: X
authors.lastname: Yang
authors.forename: Joachim
authors.initials: J
authors.lastname: Loos
authors.forename: Sjoerd C
authors.initials: SC
authors.lastname: Veenstra
authors.forename: Wiljan J H
authors.initials: WJ
authors.lastname: Verhees
authors.forename: Martijn M
authors.initials: MM
authors.lastname: Wienk
authors.forename: Jan M
authors.initials: JM
authors.lastname: Kroon
authors.forename: Matthias A J
authors.initials: MA
authors.lastname: Michels
authors.forename: René A J
authors.initials: RA
authors.lastname: Janssen