title: Excited state dynamics of organic semi-conducting materials.
abstract: Time-resolved absorption and emission spectroscopy has been applied to investigate the dynamics of excited state processes in oligomer models for semi-conducting organic materials. Following the photo-excitation of a pentamer oligomer that is a model for the conjugated polymer MEH-PPV, an ultrafast component of a few picoseconds is observed for the decay of the initially formed transient species. Variable temperature absorption and emission spectra combined with X-ray crystallography and calculations support the assignment of this rapid relaxation process to an excited state conformational rearrangement from non-planar to more planar molecular configurations. The implications of the results for the overall photophysics of conjugated polymers are considered.
authors.affiliation: School of Chemistry, University of Melbourne, Melbourne, Victoria, Australia. ghiggino@unimelb.edu.au.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Ghiggino
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tilley
authors.forename: Benjamin
authors.initials: B
authors.lastname: Robotham
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
mesh_terms: D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D055668:Photochemical Processes; D011108:Polymers / Q000737:chemistry*; D012666:Semiconductors; D013057:Spectrum Analysis / Q000379:methods; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D011108:Polymers; D014753:Vinyl Compounds; C520682:poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene)