Browsing by Author "Tutuncu, Esra"

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Electrochemical and Optical Characterization of a Multielectrochromic Copolymer Based on 3,4-Ethylenedioxythiophene and Functionalized Dithienylpyrrole Derivative
(Pergamon-elsevier Science Ltd, 2019) Tutuncu, Esra; Ozkut, Merve Icli; Balci, Burcu; Berk, Hasan; Cihaner, Atilla
A novel conjugated copolymer, namely poly(3,4-ethylenedioxythiophene-co-1-(3,5-bis(trifluoromethyl)phenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole) (P(EDOT-co-1)) was synthesized via electropolymerization method from a mixture of 3,4-ethylenedioxythiophene and 1-(3,5-bis(trifluoromethyl)phenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole comonomers. The corresponding copolymer has an optical band gap of 1.7 eV and 41% optical contrast at 525 nm with a coloration efficiency of 258 cm(2)/C and 1.4 s switching time. The copolymer has a multi-electrochromic behavior: It has dark purple, purple, gray, green and cyan colors at different oxidation states. Electrochemical stability of P(EDOT-co-1) copolymer was also investigated and it was observed that the copolymer retained 86% of its stability under ambient conditions in the presence of oxygen (without purging the electrolyte solution with any inert gas) according to the current density and 83% according to the deposited charge even after 1000 redox cycles.
An Electrochromic Polymer Based on Cyclopenta[2,1-B;3,4 Effect of a Single Atom Alteration on the Electrochemical and Optical Properties of the Polymer Backbone
(Elsevier Science Sa, 2020) Tutuncu, Esra; Varlik, Bengisu; Kesimal, Busra; Cihaner, Atilla; Ozkut, Merve Icli
An electrochromic polymer, namely "poly(2,6-(3,3-didecyl-3,4-dihydro-2H-thieno [3,4-b] [1,4]dioxepin-6-yl)-4,4-dioctyl-4H-cyclopenta[2,1-b;3,4-b']dithiophene)" (P1), was electrochemically synthesized successfully, and its electrochemical and optical properties were investigated. The band gap of the polymer P1 was calculated as 1.77 eV with -5.45 eV Highest Occupied Molecular Orbital (HOMO) and -3.68 eV Lowest Unoccupied Molecular Orbital (LUMO) energy levels. The polymer P1 is bluish purple when neutralized and highly transparent greenish purple when oxidized. This color change was observed around 1.4 s between its redox states and optical contrast ratio was found to be as 49 % and 53 % with 234 cm(2)/C and 239 cm(2)/C coloration efficiencies at 590 nm and 634 nm, respectively. Moreover, the properties of this polymer were compared to its analogues and also during this comparison the effect of alteration of a single atom in the pendant unit was tried to be understood.
A Low Band Gap Polymer Based on Selenophene and Benzobis (Thiadiazole)
(Pergamon-elsevier Science Ltd, 2017) Abdulrazzaq, Mohammed; Ozkut, Merve Icli; Gokce, Gurcan; Ertan, Salih; Tutuncu, Esra; Cihaner, Atilla
A new derivative of benzobis(thiadiazole) based donor-acceptor-donor type monomers, namely 4,7-di (selenophen-2-yl)benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole (SeBTSe), was synthesized and its polymerization was carried out successfully via electrochemical polymerization in an electrolyte solution of 0.1 M tetrabutylammonium hexafluorophosphate dissolved in dichloromethane. The monomer SeBTSe is a deep red chromophore and it has four redox states: one oxidation, one neutral and two reduction states. The electrochemical behaviour of the corresponding polymer called PSeBTSe was studied by cyclic and differential pulse voltammetry. There is a good agreement between electrochemical (0.62-0.66 eV) and optical (0.63 eV) bandgaps of the polymer. Like the monomer, the ambipolar polymer has four redox states and electrochromic properties: gray beige at neutral state, smoky azurite at oxidized state, beige at first reduced state and dark beige at second reduced state. (C) 2017 Elsevier Ltd. All rights reserved.
Synthesis and Electropolymerization of a Donor-Acceptor Trimeric Monomer Containing 3,4-Propylenedioxythiophene and Dithienosilole Units
(Pergamon-elsevier Science Ltd, 2019) Tutuncu, Esra; Cihaner, Atilla; Ozkut, Merve Icli
A new dithienosilole and 3,4-propylenedioxythiophene based monomer, namely 2,6-bis(3,3-di-decyl-3,4-dihydro-2H-thieno[3,4-b] [1,4]dioxepin-6-yl)-4,4-dioctyl-4H-silolo[3,2-b:4,5-b']dithiophene, was synthesized via palladium catalyzed Stille Coupling Reaction and then polymerized electrochemically in an electrolyte solution of 0.1 M lithium perchlorate dissolved in a mixture of dichloromethane and acetonitrile (1:1, v:v). Due to the presence of long alkyl chains on donor and acceptor units, the corresponding polymer was soluble in common organic solvents like tetrahydrofuran, toluene, hexane and dichloromethane. Polymer has both fluorescent and electrochromic properties. Fluorescent polymer emits a reddish pink at 585 nm when excited at 480 nm and the quantum yield was found as 14%. On the other hand, the electrochromic polymer film changed its color from purple to transmissive cyan with 0.65 s switching time upon moving from neutral state to oxidized state and the film has a coloration efficiency of 501 cm(2)/C as well as 60% optical contrast. The optical band gap of the polymer was also calculated as 1.83 eV with a maximum wavelength at 577 nm.
Synthesis of an Anthracene-Based Monomer and Its Electrocopolymerization With 3,4-Ethylenedioxythiophene
(Electrochemical Soc inc, 2019) Tutuncu, Esra; Ozkut, Merve Icli
First, the polymer 9,10-di(3,3-didecyl-3,4-propylenedioxythiophen-2-yl)anthracene-co-3,4-propylenedioxythiophene (A) was synthesized from 9,10-dibromoanthracene and tributyl(3,3-didecyl-3,4-propylenedioxythiophen-2-yl)stannane via Stille Coupling reaction. Next, A was electrochemically copolymerized with 3,4-ethylenedioxythiophene to form poly(9,10-di(3,3-didecyl-3,4-propylenedioxythiophen-2-yl)anthracene-co-3,4-propylenedioxythiophene) (P(A-co-EDOT)). The resulting copolymer's electrochemical, optical and electrochromic properties were then investigated. P(A-co-EDOT) was found to have the electrochromic property: It is dark navy in its neutral state and changes color to dark cyan in its oxidized state. Coloration efficiency of the copolymer was calculated as 142 cm(2)/C, with a 0.7 s switching time at 580 nm wavelength. (C) 2019 The Electrochemical Society.