Browsing by Author "Ozkut, Merve Icli"

Now showing 1 - 12 of 12

[1,2,5]thiadiazolo[3,4-G]quinoxaline Acceptor-Based Donor-Acceptor Polymers: Effect of Strength and Size of Donors on the Band Gap
(Wiley, 2017) Gokce, Gurcan; Karabay, Baris; Cihaner, Atilla; Ozkut, Merve Icli
Electrochromic polymers based on [1,2,5]thiadiazolo[3,4-g]quinoxaline acceptor and thiophene, 3,4-ethylenedioxythiophene and 3,3-didecyl-3,4-proylenedioxythiophene donors, namely poly(6,7-diphenyl-4,9-di(thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline) (P1), poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)-6,7-diphenyl-[1,2,5]thiadiazolo[3,4-g]quinoxaline) (P2), and poly(4-(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-9-(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-8-yl)-6,7-diphenyl-[1,2,5]thiadiazolo[3,4-g]quinoxaline) (P3), respectively, were electrochemically and/or chemically synthesized and characterized. Electrochemical and optical properties of the polymers were then investigated. The results, which were obtained electrochemically and optically, indicate that the polymers bearing the same acceptor and different donor units have a band gap range of 0.59-1.24 eV depending on the strength and size of the donor units and band gap determination method. A significant finding in this study was the phenomenon that when the acceptor is physically huge, the general rule that a weak donor would have a high band gap whereas a strong donor would have low band gap can be broken due to the torsional angles/steric hindrances involved with physically large donor molecules. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3483-3493
A Camouflage Material: P- and N-Type Dopable Furan Based Low Band Gap Electrochromic Polymer and Its Edot Based Copolymer
(Pergamon-elsevier Science Ltd, 2015) Kavak, Emrah; Us, Cansu N.; Yavuz, Ejmer; Kivrak, Arif; Ozkut, Merve Icli
A Donor-Acceptor-Donor (D-A-D) type monomer, 4,9-di(furan-2-yl)-6,7-diphenyl-[1,2,5]thiadiazolo[3,4g] quinoxaline (1), was synthesized via Stille Coupling reaction and polymerized electrochemically. The obtained polymer (P1) has low band gap (0.85 eV) and showed electrochromic property (pale mustard-colored in neutral state, grey in oxidized state and brown in reduced state). Moreover, copolymerization of 1 was carried out with EDOT for the formation of P(1-co-EDOT) which exhibits higher electrochemical stability than its homopolymer (P1) and have intriguing electrochromic property with a color change from the tunes of brown to the tunes of green. The band gap of copolymer was calculated as 1.1 eV. (C) 2015 Elsevier Ltd. All rights reserved.
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.
Electrochemical Synthesis of Poly(6,7-Diphenyl and Its Electrochemical and Optical Characterizations
(Springer, 2024) Smail, Sardar Kareem; Gokce, Gurcan; Ozkut, Merve Icli
In this study, electrochemical copolymerization of 6,7-diphenyl-4,9-di(selenophen-2-yl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline and 3,3'-didecyl-3,4-propylenedioxythiophene is carried out to obtain a copolymer namely poly(6,7-diphenyl-4,9-di(selenophen-2-yl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline-co-3,3'-didecyl-3,4-propylenedioxythiophene). Two distinct copolymers, PC1 and PC2, were produced as a result of the utilization of two different feed ratios. Copolymers were examined electrochemically and spectroelectrochemically after the copolymerization procedure. This study's major goal is to combine the exceptional characteristics of homopolymers P1 and P2 (P1 has a low band gap but is not soluble, and P2 is soluble and has a larger band gap) into a single copolymeric material.
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.
Expanding the Realm of Soluble Narrow Band Gap Polymers With a Benzobisthiadiazole Derivative
(Amer Chemical Soc, 2016) Us, Cansu N.; Ozkut, Merve Icli
A donor acceptor donor based soluble and narrow band gap pi-conjugated electrochromic polymer, poly(4,8-bis(3,3-dihexyl-3,4-dihydro-2H-thieno [3,4-b] [1,4] dioxepin-5-yl)b enzo [1,2c;4,5-c']bis[1,2,5]thiadiazole) (P1), was electrochemically (P1-E) and chemically (P1-C) synthesized. Cyclic voltammetry and UV-vis-NIR absorption measurements showed that P1 has a low band gap ranging from 0.59 to 1.1 eV, depending on the band gap determination and synthesis (chemical or electrochemical) methods. P1 demonstrated an ambipolar electrochemical behavior. The color of the polymer was gray in its neutral state and switched to green (first oxidation state) and blue (second oxidation state) upon oxidation and to brown upon reduction.
From Narrow To Narrower: a Very Low Band Gap [1,2,5]thiadiazolo[3,4-G]quinoxaline Donor-Acceptor Type Electrochromic Polymer
(Electrochemical Soc inc, 2017) Gokce, Gurcan; Karabay, Baris; Cihaner, Atilla; Ozkut, Merve Icli
The development of low bandgap polymers (or zero bandgap polymers) is still one of the main goals of scientists and many viable paths have been formulated in order to accomplish this. In this study, a donor-acceptor-donor type electrochromic polymer based on [1,2,5]thiadiazolo[3,4-g]quinoxaline acceptor and selenophene donor units with extremely low bandgap (ranging from 0.21 to 0.60 eV depending on bandgap determination method) is synthesized and characterized electrochemically, optically and colorimetrically. Electrochemical and optical studies showed that the polymer film was susceptible to both n- and p-type doping and has a mustard color in its neutral state, and upon oxidation its color changed to brown, and upon reduction the color is light purple. (C) 2017 The Electrochemical Society. All rights reserved.
An Indolocarbazole Based Yellow-To Soluble Electrochromic Polymer
(Elsevier Science Bv, 2018) Gokce, Gurcan; Ozkut, Merve Icli
A new donor-acceptor-donor type polymer called poly(3,9-(3,3-didecyl-3,4-propylenedioxythiophene)-5,11-di-hydroindolo[3,2-b] carbazole) (P1) was synthesized and characterized electrochemically, spectro-electrochemically and colorimetrically. P1 shows multielectrochromic property; it is yellow in neutral state, and it changes color from yellow to khaki upon oxidation. Further oxidation causes the khaki color to turn green and then green to cyan, and upon reduction, the color changes from yellow to orange. P1 also has capacitance property and is soluble in common organic solvents. Its band gap was also electrochemically determined as 1.38 eV from cyclic voltammetry and 1.50 eV from differential pulse voltammetry, while optically, it was determined as 1.56 eV.
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.
Members of Cmy Color Space: Cyan and Magenta Colored Polymers Based on Oxadiazole Acceptor Unit
(Amer Chemical Soc, 2012) Ozkut, Merve Icli; Algi, Melek Pamuk; Oztas, Zahide; Algi, Fatih; Onal, Ahmet M.; Cihaner, Atilla
In this study, three novel oxadiazole-based polymers were synthesized and their electrochemical and optical properties were investigated. The polymers were found to have both p- and n-type doping properties accompanied by electrochromic response. Two polymer films exhibit cyan and magenta colors, which constitute two legs of CMY color spaces, in their neutral states and they are soluble in common-organic solvents. According to the color mixing theory, all colors in the visible spectrum including black color can be obtained by using these polymers with a yellow colored electrochromic polymer. Among these polymers, the polymer bearing propyledioxythiophene donor units has some superior properties like high stability (it retains 94% of its electroactivity after 2000 cycles), solubility, and high coloration efficiency (230 cm(2)/C), whereas as expected ethylenedioxythiophene containing one has the lowest band gap as 1.08 eV.
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.