title: Multifrequency EPR analysis of the positive polaron in I2-doped poly(3-hexylthiophene) and in poly[2-methoxy-5-(3,7-dimethyloctyloxy)]-1,4-phenylenevinylene.
abstract: The W-band continuous-wave electron paramagnetic resonance (EPR) analysis of chemically induced polarons in drop-cast and spin-coated polyphenylenevinylene-type and polythiophene-type polymer films reveals rhombic g tensors in both cases. The dependence of the W-band EPR signals on the orientation of the spin-coated films with respect to the magnetic field indicates a high degree of backbone alignment with the substrate and allows a partial assignment of the g tensor orientation. The derived molecular orientations of the polymer chains in the spin-coated films show clear differences between the two types of polymers. The proton hyperfine interactions obtained from X-band HYSCORE (hyperfine sublevel correlation) and Q- and W-band pulsed ENDOR (electron-nuclear double resonance) experiments are interpreted in terms of earlier theoretical studies on the extension of the polarons.
authors.affiliation: University of Antwerp, Department of Physics, Universiteitsplein 1, B-2610, Antwerp (Wilrijk), Belgium. sabine.vandoorslaer@ua.ac.be.
authors.forename: Aránzazu
authors.initials: A
authors.lastname: Aguirre
authors.forename: Peter
authors.initials: P
authors.lastname: Gast
authors.forename: Sergey
authors.initials: S
authors.lastname: Orlinskii
authors.forename: Ikuko
authors.initials: I
authors.lastname: Akimoto
authors.forename: Edgar J J
authors.initials: EJ
authors.lastname: Groenen
authors.forename: Hassane
authors.initials: H
authors.lastname: El Mkami
authors.forename: Etienne
authors.initials: E
authors.lastname: Goovaerts
authors.forename: Sabine
authors.initials: S
authors.lastname: Van Doorslaer