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Peres, L. O., Wang, S. H., Wery, J., Froyer, G. & Faulques, E. (2009) Novel blue emitters based on pi-conjugated block copolymers. Mater. Sci. Eng. C-Biomimetic Supramol. Syst. 29 372–376.
Added by: Laurent Cournède (2016-03-10 21:41:24) |
| Type de référence: Article DOI: 10.1016/j.msec.2008.07.022 Numéro d'identification (ISBN etc.): 0928-4931 Clé BibTeX: Peres2009 Voir tous les détails bibliographiques  |
Catégories: PMN Mots-clés: conjugated polymers, copolymers, Fluorene, photoluminescence, pyrazine, pyridazine, pyrimidine, spectra, Suzuki reaction, transistors, Vibrational spectroscopy Créateurs: Faulques, Froyer, Peres, Wang, Wery Collection: Mater. Sci. Eng. C-Biomimetic Supramol. Syst. |
Consultations : 1/554
Indice de consultation : 4% Indice de popularité : 1% |
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A series of new phenyl-based conjugated copolymers has been synthesized and investigated by vibrational and photoluminescence spectroscopy (PL). The materials are: poly( 1,4-phenylene-alt-3,6-pyridazine) (COP-PIR), poly(9,9-dioctylfluorene)-co-quaterphenylene (COP-PPP) and poly[(1,4-phenylene-alt-3,6-pyridazine)-co-(1,4-phenylene-alt-9,9-dioctylfluorene)] (COP-PIR-FLUOR), with 3.5\% of fluorene. COP-PPP and COP-PIR-FLUOR have high fluorescence quantum yields in solution. Infrared and Raman spectra were used to check the chemical structure of the compounds. The copolymers exhibit blue emission ranging front 2.8 to 3.6 eV when excited at E(exc)=4.13 eV. Stokes-shift Values were estimated on pristine samples in their condensed state from steady-state PL-emission and PL-excitation spectra. They suggest a difference in the torsional angle between the molecular configuration of the polymer blocks at the absorption and PL transitions and also in the photoexcitation diffusion. Additionally, the time-resolved PL of these materials has been investigated by using 100 fs laser pulses at E(exc)=4.64 eV and a streak camera. Results show very fast biexponential kinetics for the two fluorene-based polymers with decay times below 300 ps indicating both intramolecular, fast radiative recombination and migration of photogenerated electron-hole pairs. By contrast, the PL of COP-PIR is less intense and longer lived, indicating that excitons are confined to the chains in this polymer. (C) 2008 Elsevier B.V. All rights reserved.
Added by: Laurent Cournède |