title: Infrared spectroscopic signatures of phase segregation in P3HT-porphyrin blends.
abstract: Phase segregation of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine ruthenium(II)carbonyl (RuOEP) and regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) in thin films is investigated with infrared and UV-visible spectroscopies as well as transmission electron microscopy (TEM). The Fourier transform infrared (FTIR) spectrum of the ruthenium-bound CO symmetric stretching mode exhibits significant changes as these films are annealed in solvent vapors. The development of multiple inhomogeneously broadened microenvironments is observed, and UV-visible spectra and TEM support a model of homogeneous porphyrin distribution throughout the P3HT films that gradually becomes more heterogeneous as the P3HT and RuOEP molecules phase segregate. A complete model for the phase segregation process experienced by the embedded RuOEP is proposed to explain the collective experimental observations.
authors.affiliation: Department of Chemistry, University of Minnesota, Twin Cities, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA.
authors.forename: Audrey A
authors.initials: AA
authors.lastname: Eigner
authors.forename: Patrick E
authors.initials: PE
authors.lastname: Konold
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Massari