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Article Citation - WoS: 2Citation - Scopus: 2New electrochromic copolymers based on spiro bipropylenedioxythiophene and 3,4-ethylenedioxythiophene(Elsevier Science Sa, 2014) Pekel, Lutfiye Canan; Karabay, Bads; Cihaner, AtillaTwo alkylenedioxythiophene derivatives, Spiro bipropylenedioxythiophene (Spiro-BiProDOT) and 3,4-ethylenedioxythiophene (EDOT), were integrated electrochemically in order to attain low band gap electrochromic copolymers. EDOT has a functionality of two, which causes a linear polymer, whereas Spiro-BiProDOT has a functionality of four and its polymerization results in a network polymer. Therefore, by playing the monomer feed ratio, the crosslink degree can be adjusted for the copolymers obtained electrochemically from EDOT and Spiro-BiProDOT monomers in an electrolyte solution of 0.1 M tetrabutyl ammonium hexafluorophosphate dissolved in dichloromethane. It was found that copolymers showed different electrochemical and optical properties at their various redox states when compared to their homopolymers. For example, they could be switched from dark blue in the neutral state to reddish blue at intermediate state and finally to transparent blue in the oxidized state with 45-51% of the transmittance change at 575-595 nm. pi-pi* transition bands of the copolymers can be shifted to higher wavelengths when compared to poly(Spiro-BiProDOT) by increasing the amount of the EDOT units in the polymer backbone. They have low band gaps in the range of 1.65 and 1.73 eV. (C) 2014 Elsevier B.V. All rights reserved.Article Citation - WoS: 8Citation - Scopus: 8Improvement of Optical Properties and Redox Stability of Poly(3,4-Ethylenedioxythiophene)(Elsevier Sci Ltd, 2018) Ertan, Salih; Cihaner, AtillaIn order to improve the optical properties and redox stability of poly(3,4-ethylenedioxythiophene) (PEDOT) without changing its electrochemical and electrochromic behaviour, it was supported with alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage. The corresponding copolymers were obtained electrochemically via potentiostatic or potentiodynamic methods and compared to the parent homopolymers. Electrochemical polymerization of EDOT and POSS containing EDOT called EDOT-POSS in various monomer feed ratios was performed in an electrolyte solution of 0.1 M TBAPF(6) dissolved in a mixture of dichloromethane and acetonitrile (1/3: v/v). Just as PEDOT, the copolymers represented the similar band gap (1.61 eV), redox and electrochromic behaviors. On the other hand, when compared to the parent PEDOT, the presence of POSS cages in the copolymer backbone improved the redox stability and optical properties of PEDOT such as higher percent transmittance change (65% at 621 nm), higher transparency at oxidized state, lower switching time (similar to 1.0 s) and higher coloration efficiency (463 cm(2)/C for 95% switching) as well as higher electrochemical stability (86% of its electroactivity retains after 1750 cycles under ambient conditions).Article Citation - WoS: 11Citation - Scopus: 11Electrochemical and Optical Properties of Substituted Phthalimide Based Monomers and Electrochemical Polymerization of 3,4-Ethylenedioxythiophene Oligomeric Silsesquioxane (poss) Analogue(Elsevier Sci Ltd, 2019) Cakal, Deniz; Ertan, Salih; Cihaner, Atilla; Onal, Ahmet M.A new series of donor-acceptor-donor type trimeric monomers bearing substituted phthalimide units as acceptor units and thiophene and 3,4-ethylenedioxythiophene (EDOT) as donor units was synthesized and characterized. The strength of acceptor units and intramolecular charge transfer between donor and acceptor units were investigated by using electrochemical and optical methods. The main advantage of phthalimide unit over other acceptor units is the ease of its functionalizability. Thus, utilizing this property, a phthalimide derivative (E2P-POSS) bearing polyhedral oligomeric silsesquioxane (POSS) cage was introduced successfully with EDOT and polymerized electrochemically. The corresponding electroactive polymer, PE2P-POSS, has a band gap of 1.72 eV and is an electrochromic polymer: gray when neutralized and eggplant purple when oxidized.Article Citation - WoS: 26Citation - Scopus: 28A New Electrochromic Copolymer Based on Dithienylpyrrole and Edot(Elsevier Science Bv, 2013) Algi, Melek Pamuk; Oztas, Zahide; Tirkes, Seha; Cihaner, Atilla; Algi, FatihA new compound, namely diethyl 2,5-di(thiophen-2-yl)-1H-pyrrole-3,4-dicarboxylate (1), was copolymerized with 3,4-ethylenedioxythiophene (EDOT) via electrochemical method. The copolymer exhibits multicolor electrochromic property: It is found that the copolymer, poly(1-co-EDOT), has a specific optical band gap (1.71 eV) to reflect and/or transmit reddish brown color in the neutral state, and it can be switched to reddish orange, orange, yellowish green and blue colors upon oxidation in a low switching time (1.0 s). Importantly, these colors are essential for camouflage and/or full color electrochromic device/display applications. In addition to these, the obtained copolymer has a coloration efficiency of 173 cm(2)/C at 500 nm. (C) 2013 Elsevier B.V. All rights reserved.Article Citation - WoS: 16Citation - Scopus: 17A New Carborane Based Polymeric Electrochrome(Elsevier Science Sa, 2013) Cansu-Ergun, Emine Gul; Cihaner, AtillaNew electrochromic copolymers of 3,4-ethylenedioxythiophene and di(m-carboranyl thiophene) were synthesized, characterized and their electro-optical properties were reported. The copolymers were successfully prepared from various monomer feed ratios using electrochemical polymerization technique. It can be conjectured that electrochemical and optical properties of the copolymers can be adjusted by playing with monomer feed ratios. For example, the maximum wavelength of poly(3,4-ethylenedioxythiophene) at 600 nm can be shifted to lower values (i.e., 522 nm) by increasing the ratio of di(m-carboranyl thiophene) in the monomer mixture. The copolymer films also have low band gap values between 1.69 and 1.82 eV and showed electrochromic properties; purple when neutralized and transparent sky blue when oxidized. Also, during redox switching the films exhibited a percent transmittance change between 32% and 46% with a switching time between 1.0 s and 1.3 s. (C) 2013 Elsevier B.V. All rights reserved.Article Citation - WoS: 33Citation - Scopus: 34An ambipolar neutral state green polymeric electrochromic(Elsevier, 2009) Algi, Fatih; Cihaner, AtillaThe synthesis and properties of highly stable neutral state green polymeric electrochromic, P1, which is based on 5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,3-di(1H-pyrrol-2-yl)quinoxaline were highlighted. P1 exhibits three well-defined absorption bands with a narrow band gap (1.17 eV). The n- and p-doping (ambipolar) processes suggest that P1 is one of the most promising neutral state green polymers and it can be used in supercapacitors as either cathode or anode electrode material. Apart from the stability and the robustness of the polymer film, P1 shows multi-electrochromic behavior; gray-purple in the reduced form and highly transmissive blue color in the oxidized state. (C) 2009 Elsevier B.V. All rights reserved.Article Citation - WoS: 9Citation - Scopus: 10Effect of Ring Size on Benzimidazole Unit on Electro-Optical Properties of Donor-Acceptor Type Monomers and Their Polymers(Elsevier Science Sa, 2016) Al-Ogaidi, Saad; Karabay, Bads; Karabay, Lutfiye Canan; Cihaner, AtillaA new series of fluorescent donor-acceptor-donor (D-A-D) type monomers based on benzimidazole acceptor unit bearing various cycloalkane appendages, called 4,7-di-2,3-dihydrothieno[3,4-b] [1,4]dioxin-5-ylspiro[benzimidazole-2,1'-cyclopentane] (E5E), 4,7-di-2,3-dihydrothieno[3,4-b] [1,4]dioxin-5-ylspiro[benzimidazole-2,1'-cyclohexane] (E6E) and 4,7-di-2-thienylspiro[benzimidazole-2,1'-cyclohexane] (T6T), were synthesized and polymerized via potentiostatic and potentiodynamic methods. The effect of ring size on benzimidazole unit and the kind of donor moiety in D-A-D system on the electrochemical and optical properties have been studied systematically. The optical studies showed that the ring size of the benzimidazole unit has no effect on the absorbance and fluorescence properties, whereas the oxidation potential of the E5E, E6E and T6T monomers varied with respect to both the ring size and the kind of donor unit: 0.89 V, 0.83 V and 122 V vs Ag/AgCl, respectively. All polymers have ambipolar (p- and n-type doping) and electrochromic properties. While the polymer films PE5E and PE6E are green at neutral state and transparent at oxidized state, the polymer PT6T has no appreciable color change between its neutral and oxidized states. The polymers PE5E and PE6E bearing 3,4-ethylenedioxythiophene unit as donor units exhibited lower band gap values (1.21 eV and 1.18 eV, respectively) than the polymer PT6T (1.53 eV). When compared to PT6T, PE5E and PE6E polymers are more stable under ambient condition. While PE5E retained 76% of its electroactivity after 4000 cycles, PE6E has 65% of its electroactivity after 2000 cycles. (C) 2016 Elsevier B.V. All rights reserved.
