dc.contributor.author | Paudel, Keshab Raj, 1973- | eng |
dc.contributor.author | Chandrasekhar, Meera | eng |
dc.contributor.author | Guha, Suchi | eng |
dc.date.issued | 2009 | eng |
dc.description.abstract | Polyfluorenes (PFs) represent a unique class of poly para-phenylene based blue-emitting polymers with intriguing structure-property relationships. Slight variations in the choice of functionalizing side chains result in dramatic differences in the inter- and intra-chain structures in PFs. We present photoluminescence (PL) and Raman scattering studies of bulk samples and thin films of dioctyl-substituted PF (PF8) under hydrostatic pressure. The bulk sample was further thermally annealed at 1.9 GPa. The PL vibronics of the as-is sample red-shift at an average rate of 26 meV/GPa. The thermally annealed sample is characterized by at least two phase transitions at 1.1 GPa and 4.2 GPa, each of which has a different pressure coefficient for PL vibronics. The Huang-Rhys factor, a measure of the electron-phonon interaction, is found to increase with increasing pressures signaling a higher geometric relaxation of the electronic states. The Raman peaks harden with increasing pressures; the intra-ring C-C stretch frequency at 1600 cm$^{-1}$ has a pressure coefficient of 7.2 cm$^{-1}$/GPa and exhibits asymmetric line shapes at higher pressures, characteristic of a strong electron-phonon interaction. The optical properties of PF8 under high pressure are further contrasted with those of a branched side chain substituted PF. | eng |
dc.description.sponsorship | This work was partly supported through the National Science Foundation under grant
No. ECCS-0523656. | eng |
dc.identifier.citation | arXiv:0905.1736v1 | eng |
dc.identifier.uri | http://hdl.handle.net/10355/6804 | eng |
dc.language | English | eng |
dc.publisher | arXiv | eng |
dc.relation.ispartofcollection | University of Missouri--Columbia. College of Arts and Sciences. Department of Physics and Astronomy. Physics and Astronomy publications | eng |
dc.source.uri | http://arxiv.org/PS_cache/arxiv/pdf/0905/0905.1736v1.pdf | eng |
dc.subject | soft condensed matter | eng |
dc.subject | materials science | eng |
dc.subject | polyfluorenes | eng |
dc.subject.lcsh | Hydrostatic pressure | eng |
dc.subject.lcsh | Fluorene | eng |
dc.subject.lcsh | Polymers -- Optical properties | eng |
dc.title | Tuning intermolecular interactions in di-octyl substituted polyfluorene via hydrostatic pressure | eng |
dc.type | Article | eng |