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Title: Copolymers of 3,4-ethylenedioxythiophene and of pyridine alternated with fluorene or phenylene units: Synthesis, optical properties, and devices
Authors: AUBERT, Pierre-Henri
Groenendaal, L
LUTSEN, Laurence
Issue Date: 2004
Citation: MACROMOLECULES, 37(11). p. 4087-4098
Abstract: We report the synthesis of four conjugated copolymers based on alkylated fluorene or phenylene units which band gap is tuned by the regular insertion of an electron-donating or electron-withdrawing unit, (3,4-ethylenedioxy)thiophene and pyridine, respectively. The (AB)(n) regular sequence is achieved by Suzuki polycondensation reactions. The characterization of the copolymers by size exclusion chromatography reveals chains lengths of about 20-30 repeat units (40-60 rings), leading to a good processability for potential optical applications. The 1:1 ratio between the two units improves the solubility of the material in common organic solvents, allowing for physicochemical characterizations. Raman and FT-IR experiments indicate that the electronic structure of the backbone is rather benzenic in the neutral (undoped) state, as opposed to a quinoic oxidized structure. All copolymers exhibit interesting electro-chromic properties as attested by cyclic voltammetry and UV-vis experiments. They reversibly switch among the entire visible spectra, which is of particular importance for display applications. Moreover, the EDOT-based copolymers strongly absorb in the NIR window (1200 nm up to 3000 nm) with some potential electrochromic applications related to this spectral window. Light-emitting diodes were fabricated using these copolymers as active layer. To improve hole and electron injection, the active layer was sandwiched between a ITO/PEDOT:PSSA/copolymer/Ba/Al. The emitting properties were studied on the base of photoluminescence (PL) and electroluminescence (EL) experiments. The spectral emission varies from blue-green to yellow, depending on the composition of the copolymers.
Notes: IMEC, IMOMEC Div, SBG OS, B-3590 Diepenbeek, Belgium. Limburgs Univ Ctr, Grp Organ & Polymer Chem, SBG, B-3590 Diepenbeek, Belgium. AGFA Gevaert, Dept Chem, RM D, B-2640 Mortsel, Belgium.Vanderzande, D, IMEC, IMOMEC Div, SBG OS, Wetenschapspk 1, B-3590 Diepenbeek, Belgium.dirk.vanderzande@luc.ac.be
URI: http://hdl.handle.net/1942/2430
DOI: 10.1021/ma030540r
ISI #: 000221688600023
ISSN: 0024-9297
Category: A1
Type: Journal Contribution
Validation: ecoom, 2005
Appears in Collections: Research publications

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