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Article Citation - WoS: 24Citation - Scopus: 25A Novel Conducting Polymer Based on Terthienyl System Bearing Strong Electron-Withdrawing Substituents and Its Electrochromic Device Application(Elsevier Science Sa, 2008) Asil, Demet; Cihaner, Atilla; Algi, Fatih; Onal, Ahmet M.A novel conducting polymer bearing strong electron-withdrawing substituents (EWS) directly attached to the 3,4-positions of the thiophene ring was synthesized by electrochemical polymerization of diethyl 2,5-di(thiophen-2-yl)thiophene-3,4-dicarboxylate (SSS-Diester). The polymer (PSSS-Diester) was characterized by cyclic voltammetry, FT-IR and UV-vis spectroscopy. The polymer has a reversible redox process and demonstrates a stable electrochromic behavior: reddish orange in the neutral state, brown in the intermediate state and green in the oxidized state. Optical density and response time of the dual-type electrochromic device based on PSSS-Diester were found to be 0.23 and 0.6 s at 623 nm, respectively. It is also noteworthy that the device shows good environmental and redox stability (i.e. 94% of the optical activity of the device retained after 500th switch). (c) 2008 Elsevier B.V. All rights reserved.Article Citation - WoS: 26Citation - Scopus: 30Electrochemical Polymerization of 9-Fluorenecarboxylic Acid and Its Electrochromic Device Application(Elsevier Science Sa, 2008) Bezgin, Buket; Cihaner, Atilla; Onal, Ahmet M.Poly(9-fluorenecarboxylic acid) (PFCA) was synthesized by electrochemical oxidation of 9-fluorenecarboxylic acid (FCA) using a mixture of nitromethane and boron trifluoride diethyl etherate as the solvent and tetrabutylammonium tetrafluoroborate as the supporting electrolyte. An insoluble and conducting brownish-orange film was deposited on the electrode surface, both during repetitive cycling and constant potential electrolysis at 1.15 V. Characterization of the polymer film has been carried out using Fourier Transform Infrared spectroscopy technique and thermal behavior was studied via thermal gravimetric analysis. Structural analysis showed that the polymerization of FCA occurred at 2,7-position. Spectroelectrochemical behavior of the polymer film on indium tin oxide working electrode was studied by recording the electronic absorption spectra, in-situ, in monomer-free electrolytic solution at different potentials and it is found that the PFCA film can be reversibly cycled between 0.0 V and 1.2 V Furthermore, a dual type electrochromic device based on PFCA was constructed and its spectroelectrochemical properties were investigated. The electrochromic device exhibits color change from transparent to dark blue with a good open circuit memory. (c) 2008 Elsevier B.V. All rights reserved.Article Citation - WoS: 25Citation - Scopus: 26Electrochemical Synthesis of Poly(3-Bromo and Its Device Application(Elsevier Science Sa, 2007) Cihaner, Atilla; Onal, Ahmet M.A functionalized thiophene containing both an electron withdrawing and an electron donating group, 3-bromo-4-methoxythiophene (BrMeOTh) was succesfully polymerized in acetonitrile containing 0.1 M tetrabutylammonium tetrafluoroborate (TBABF4) electrolyte via electrochemical oxidation of the corresponding monomer. BrMeOTh exhibits a lower oxidation potential (1.68 V vs Ag/AgCl) than thiophene (2.05 V vs Ag/AgCl). Spectroelectrochemical properties of poly(3-bromo-4-methoxythiophene) (PBrMeOTh) was investigated in situ recording the electronic absorption spectra of the polymer film coated on indium-tin oxide (ITO) at various potentials. The maximum transmittance difference between the oxidized and reduced states was measured as 39.2% and the time required to attain 90% of the total transmittance difference was found to be 1.2 s. Both cyclic voltammetric and spectroelectrochemical studies showed that the polymer exhibit a lower oxidation potential, a relatively narrow band gap, a stable conducting state and a higher degree of electrochemical reversibility. It is also found that, as synthesized PBrMeOTh films possess a linear structure along the polymer backbone. Moreover, dual type electrochromic device of PBrMeOTh with poly(3,4-diethylenedioxythiohene) (PEDOT) was constructed and its spectroelectrochemical, electrochromic switching and open circuit stability were investigated. Dual electrochromic device showed a good optical contrast and distinctive color changes with the ability of good switching times (1.1 s) under atmospheric pressure. (c) 2006 Elsevier B.V. All rights reserved.
