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Öğe Characteristics of dual-type electrochromic devices based on poly(ethylene oxide) copolymers(Wiley, 2007) Yıldız, Hüseyin Bekir; Şahin, Elif; Çırpan, Ali; Toppare, Levent; Yağcı, Yusuf; 0000-0003-3051-8380; 0000-0003-3589-8300Dual-type polymer electrochromic devices based on [(3-thienyl)methylmethacrylate]-co-[p-vinyl benzyloxy poly(ethylene oxide)]/polythiophene and thiophene-capped poly(ethylene oxide)/polythiophene and ethylene dioxythiophene were constructed via electropolymerization. Spectroelectrochemistry, switching ability and stability of the devices were investigated using UV-visible spectrophotometry and cyclic voltammetry. These devices exhibit low switching; voltages and short switching times with reasonable switching stability under atmospheric conditions.Öğe Dual-type electrochromic devices based on both n- and p-dopable poly(dithieno[3,4-b,3?,4?-e]-[1,4]-dithiine)(Elsevier Science Sa, 2006) Sahin, Elif; Camurlu, Pinar; Toppare, LeventPolydithieno[3,4-b,3'4'-e]-[1,4]-dithiine (PDTH), being both n- and p-dopable, reveals remarkable color changes as both anodically and cathodically coloring material. In order to investigate its utilization in the electrochromic devices, three different transmissive/absorbtive type polymer electrochromic devices based on both p-type and n-type PDTH were assembled. These are, namely (1) p-type PDTH/poly(3,4-ethylenedioxythiophene) (PEDOT); (2) polythiophene/n-type PDTH; (3) p-type PDTH/n-type PDTH. Spectroelectrochemistry, switching ability, stability and open-circuit memory of the devices were investigated by UV-vis spectrophotometer and cyclic voltammetry. These devices exhibit reasonable switching times and stability under atmospheric conditions. (c) 2006 Elsevier B.V. All rights reserved.Öğe Electrochromic properties of poly(diphenyldithieno[3,2-b;: 2?,3?-d]thiophene)(Elsevier Science Sa, 2006) Mert, Olcay; Sahin, Elif; Ertas, Erdal; Ozturk, Turan; Aydin, Engin A.; Toppare, LeventA conducting polymer of diphenyldithieno[3,2-b;2',3'-d]thiophene (DPhDTT) was synthesized via potentiodynamic method in dichloromethane (DCM)/acetonitrile (AN) (1:9(v/v))-NaClO4/LiClO4 (0.1:0.1 M) solvent-electrolyte couple. Characterizations of the resulting homopolymer were performed by cyclic voltarnmetry (CV), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. Moreover, the spectroelectrochemical and electrochromic properties of the homopolymer films were investigated. Consequently, P(DPhDTT)/PEDOT device was constructed and their characteristics were examined in detail. A potential range of 0.0-2.0 V was found to be suitable for operating the P(DPhDTT)/PEDOT device between yellow and blue colors. The device reveals good open circuit memory and stability. (c) 2006 Elsevier B.V. All rights reserved.Öğe A new soluble conducting polymer and its electrochromic devices(Wiley, 2006) Yıldız, Ümit Hakan; Şahin, Elif; Akhmedov, İdris Mecidoǧlu; Tanyeli, Cihangir; Toppare, Levent; 0000-0003-3589-8300A new polythiophene derivative was synthesized by both chemical and electrochemical oxidative polymerization of 1-(1-phenylethyl)-2,5-di(2-thienyl)-1H-pyrrole (PETPy). Of which the chemical method produces a polymer that is completely soluble in organic solvents. The structures of both the monomer and the soluble polymer were elucidated by nuclear magnetic resonance (H-1 and C-13 NMR) and Fourier transform infrared (FTIR) spectroscopy. The average molecular weight has been determined by gel permeation chromatography to be M-n = 3.29 x 10(3) for the chemically synthesized polymer. Polymer of PETPy was synthesized via potentiostatic electrochemical polymerization in acetonitrile (AN)/NaClO4/LiClO4 (0.1 M) solvent-electrolyte couple. Characterizations of the resulting polymer were performed by cyclic voltammetry, FTIR, scanning electron microscopy, and UV-vis spectroscopy. Four-probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the polymer films were investigated. In addition, dual-type polymer electrochromic devices based on P(PETP,) with poly(3,4-ethylenedioxythiophene) were constructed. Spectroelectrochemistry, electrochromic switching, and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts, and optical memories.Öğe Synthesis and characterization of a new soluble conducting polymer and its electrochromic devices(Elsevier, 2006) Sahin, Elif; Sahmetlioglu, Ertugrul; Akhmedov, Idris M.; Tanyeli, Cihangir; Toppare, LeventA new polythiophene derivative was synthesized by both chemical and electrochemical oxidative polymerization of 1-(perfluorophenyl)-2,5-di(2-thienyl)-1H-pyrrole (FPTPy). The structures of both the monomer and the soluble polymer were elucidated by nuclear magnetic resonance (H-1-NMR) and fourier transform infrared (FTIR). Polymer of FPTPy was also synthesized via potentiostatic electrochemical polymerization in acetonitrile (AN)/NaClO4/LiClO4 (0.1 M:0.1 M) Solvent-electrolyte couple. Characterizations of the resulting insoluble polymer were performed by cyclic voltammetry (CV), FTIR, scanning electron microscopy (SEM) and UV-Vis Spectroscopy. Four-probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the polymer film were investigated. In addition, dual type polymer electrochromic devices (ECDs) based on P(FPTPy) with poly(3,4-ethylenedioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts and optical memories. (C) 2006 Elsevier B.V. All rights reserved.Öğe Synthesis and characterization of thiophene functionalized polystyrene copolymers and their electrochemical properties(Wiley, 2005) Şahin, Elif; Çamurlu, Pınar; Toppare, Levent; Mercore, Viorela Mihaela; Cianga, Ioan; Yağcı, Yusuf; 0000-0003-3589-8300; 0000-0003-1610-0033Thiophene functionalized polystyrene samples (TFPS) were synthesized by atom transfer radical polymerization (ATRP) of styrene, followed by Suzuki coupling with 3-thiophene (Th) boronic acid. Conducting graft polymer of TFPS with thiophene was achieved at 1.5 V in tetrabutylammonium tetrafluoroborate/dichloromethane (TBAFB/DM) by electrochemical methods. Spectroelectrochemical analysis of the resulting copolymers [P(TFPS-co-Th)] reflected electronic transitions at 449, 721 and 880 nm, revealing pi - pi* transition, polaron and bipolaron band formation, respectively. We also successfully established the utilization of dual type complementary colored polymer electrochromic devices using P(TFPS-co-Th)/poly(3,4-ethylenedioxythiophene (PEDOT) in sandwich configuration. The switching ability, stability and optical memory of the electrochromic device were investigated by UV-visible spectrophotometry and cyclic voltammetry. Device switches between brown and blue color with a switching time of 1.3 s were prepared with optical contrast (%Delta T) of 25 (c) 2005 Society of Chemical Industry.Öğe Synthesis, characterization and electrochromic properties of copolymer of 3-{[4-(thien-3-yl-methoxy)phenoxy]methyl} thiophene with thiophene(Pergamon-Elsevier Science Ltd, 2006) Erden, Ayca; Sahin, Elif; Gullu, Mustafa; Toppare, Levent(3- {[4-(Thien-3-yl-methoxy)phenoxy]methyl} thiophene) (TMPMT) was synthesized via the reaction of 3-bromomethyl-thiophene with hydroquinone and characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). Electrochemical copolymerization of TMPMT with thiophene in acetonitrile/boron trifluoride diethyl etherate (AN/BFEE) solvent mixture was achieved using tetrabutylammonium tetrafluoroborate (TBAFB) as the supporting electrolyte. Resulting copolymer was characterized via cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), four probe technique conductivity measurement and UV-Vis spectroscopy. Spectroelectrochemical analysis of the copolymer [P(TTMT-co-Th)] revealed that pi-pi* electronic transition occurs at 427 nm with a band gap value of 2.20 eV. Copolymer gives brown color at the fully reduced state whereas; at fully oxidized state the film has a gray-blue color. Kinetic studies were carried out at the maximum contrast wavelength upon measuring the percent transmittance, T% (7.6%) and switching time (2.0 s) to examine the switching ability of the copolymer. Dual type electrochromic device (ECD) of P(TMPMT-co-Th) and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed. Spectroelectrochemistry, switching ability, open circuit memory and stability of the device were examined by UV-Vis spectroscopy and cyclic voltammetry. The device switches between brown and blue at switching voltages of 0.0 V and 2.8 V with a short switching time of 1.4 s. (c) 2006 Elsevier Ltd. All rights reserved.
