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Atilim University,

Chemical Engineering and Applied Chemistry, ATOMSEL

Incek, Golbasi, 06836
Ankara-Turkey
Phone: +903125868304-8817
Fax: +903125868091
E-mail: cihaner@atilim.edu.tr

65- A Pure Blue to Highly Transmissive Electrochromic Polymer Based on Poly(3,4-propylenedioxyselenophene) with a High Optical Contrast Ratio

Baris Karabay, Lutfiye Canan Pekel, and Atilla Cihaner b_170_170_16777215_0___images_stories_65.gif

Macromolecules, 48, 1352-1357 (2015)

 

A new derivative of 3,4-propylenedioxyselenophene bearing naphthalenylmethyl appeandages on the bridge, called 3,4-dihydro-3,3-bis((naphthalen-2-yl)methyl)-2H-selenopheno[3,4-b][1,4]dioxepine (ProDOS-Np2), was synthesized and polymerized via potentiostatic and potentiodynamic methods. Electrochemically obtained polymer film (PProDOS-Np2) is pure blue at the neutral state and highly transparent at the oxidized state. An increase in the size of the substituents on the bridge resulted in an increase in the optical contrast ratio. Upon moving from naked bridge to benzyl and to naphthalenylmethyl substituents on the bridge center, the optical contrast changed from 51% to 65% and finally to 84%, which is the second highest reported optical contrast ratio in polyselenophene family. When compared to polythiophene analogue, the PProDOS-Np2has lower oxidation potential and band gap, higher optical contrast ratio, coloration efficiency, robustness and stability. The polymer film preserved its properties even after thousands of cycles under ambient conditions.

 
64- Poly(3,4-alkylenedioxyselenophenes): Past, Present, and Future

Atilla Cihaner b_170_170_16777215_0___images_stories_64.gif

Synlett, 26, 449-460 (2015)

 

Because of their optical and electronic properties, polythiophenes and their derivatives, especially poly(3,4-alkylenedioxythiophenes), are among the most promising materials in the field of electrochromic polymers. The properties of these polymers can be tuned by replacing the sulfur atom of the thiophene moiety with a selenium atom, because selenium has a lower electronegativity, a higher metallic character, a larger atomic size, and greater polarizability than sulfur. This approach has opened the door to a new and vibrant class of conjugated polymers. Today 3,4-alkylenedioxyselenophenes are thought as powerful competitors to 3,4-alkylenedioxythiophenes. Here, an overview is presented of poly(3,4-alkylenedioxyselenophenes), as one of the most attractive groups of conjugated polymers. The design, synthesis, and applications of poly(3,4-alkylenedioxyselenophenes) and their derivatives are discussed in detail and compared with the corresponding features of their thiophene analogues. The electrochemical and electrochromic properties and band gaps of poly(3,4-alkylenedioxyselenophenes) are also discussed in relation to their chemical structures.

 

 
63- Synthesis, properties, and electrochemistry of a photochromic compound based on dithienylethene and ProDOT

Melek Pamuk Algi, Atilla Cihaner, Fatih Algi b_170_170_16777215_0___images_stories_63.gif

Turkish Journal of Chemistry, 39, 139-148 (2015)

 

The synthesis, photochromic features, and electrochemistry of a novel material based on dithienylethene (DTE) and 3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (didecyl-ProDOT) units are described. It is noteworthy that 1,2-bis(5-(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-2-methylthiophen-3-yl)cyclopent-1-ene can be efficiently switched between open and closed states by light in both solution and in the solid poly(methyl metacrylate) (PMMA) matrix. It is also found that the emission of this novel compound can be switched on and off upon irradiation.

 
62- New electrochromic copolymers based on spiro bipropylenedioxythiophene and 3,4-ethylenedioxythiophene

Lutfiye Canan Pekel, Baris Karabay, Atilla Cihaner

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Journal of Electroanalytical Chemistry, 730, 26–33 (2014)

 

 

Two 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.

 
61- Design, synthesis, photochromism and electrochemistry of a novel material with pendant photochromic units

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Melek Pamuk Algi a, Atilla Cihaner b,*, Fatih Algi

Tetrahedron, 70, 5064-5072 (2014)

 

In the present work, the synthesis, photochromism and electrochemistry of a novel material 1, 1-(4-[3,4-bis(2,5-dimethyl-3-thienyl)cyclopent-3-en-1-yl]phenyl)-2,5-di-2-thienyl-1H-pyrrole, with pendant dithienylethene (DTE) photochromic units are described. It should be noted that the system 1 can be reversibly and efficiently switched between open (1o) and closed (1c) states by light in both solution and in the solid poly(methyl methacrylate) matrix. It is also noteworthy that the two isomers (1o and 1c) of this novel system 1 can be smoothly polymerized on ITO by electrochemical means. Surprisingly, the DTE unit in 1 does not retain its photochemical switching properties after immobilization onto ITO. The morphology of the polymer film was investigated by AFM analysis. Furthermore, it was found that the polymer exhibited remarkable electrochromic features that can be switched from green in the neutral state to violet state under applied external potentials without disturbing the photochromic units.

 
60-Electro-optical properties of poly[di(2-thiophenyl)carborane] and its opto-electronic application

Emine Gul Cansu-Ergun, Atilla Cihaner

Materials Chemistry and Physics, 143, 387-392 (2013)


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Electrochemical and optical properties of a hybrid carborane based polymer called poly(di(2-thiophenyl)carborane) (P1) obtained electrochemically were reported as well as its electrochromic device application. Thiophene donor units andm-carborane acceptor unit were combined under the same umbrella via donor–acceptor–donor approach to obtain di(2-thiophenyl)carborane (1). Contrary to the literature, extreme conditions like highly dried solvent or inert atmosphere were not used for polymerization and characterization. Polymer P1has an ambipolar character since it exhibited a reversible oxidation peak at a half wave potential (E1/2) of 1.08 V and a quasi reversible reduction peak at E1/2= 1.82 V vs. Ag/AgCl. The polymer film has an optical band gap of 1.95 eV with a maximum absorption band centered at 488 nm. Also, it exhibited multicolor electrochromic behavior between its reduced and oxidized states changing from dark orange to light blue. Furthermore, the electrochromic device prepared based on P1 film was stable and robust.

 
59-A new carborane based polymeric electrochrome

Emine Gul Cansu-Ergun, Atilla Cihaner

Journal of Electroanalytical Chemistry,707, 78-84 (2013)


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New 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.

 
58-Design and synthesis of new 4,4?-difluoro-4-bora-3a,4a-diaza-s-indacene based electrochromic polymers

Melek Pamuk Algi, Seha Tirkes, Salih Ertan, Emine Gul Cansu Ergun, Atilla Cihaner, Fatih Algi

Electrochimica Acta, 109, 766-774 (2013)

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Design, synthesis, optical and electrochemical properties of two novel 4,4?-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) based donor–acceptor compounds, 1 and 2, are reported in order to elucidate the structure–property relationships in BODIPY based materials. Importantly, these compounds provide opportunity to be used as crosslinkers, since they have three electroactive donor sides. Furthermore, these compounds are polymerized successfully via electrochemical polymerization. The corresponding polymers (P1 and P2) are also characterized by using electrochemical and optical methods in monomer-free electrolyte solutions. It is found that both polymers P1 and P2 exhibit reversible oxidation peaks with half wave potentials of 0.70 V and 0.98 V vs. Ag/AgCl, respectively, and they have low optical band gaps (1.88 eV for P1 and 1.72 eV for P2). It is also noted that the polymers exhibit multielectrochromic properties upon doping: P1 can be switched from pink color in the neutral state to blue color in the oxidized state and P2can be switched from transmissive pink color when neutralized to transmissive blue color when oxidized.

 
57-A New Electrochromic Copolymer Based on Dithienylpyrrole and EDOT

Melek Pamuk Algi, Zahide Öztas, Seha Tirkes, Atilla Cihaner, Fatih Algi

Organic Electronics, 14, 1094-1102 (2013)

 

b_250_210_16777215_0___images_stories_sehahocamakale4.jpgA 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 cm2/C at 500 nm.

 

 
56-Furan and Benzochalcogenodiazole Based Multichromic Polymers via Donor-Acceptor Approach

Merve Içli-Özkut, Halil Ipek, Baris Karabay, Atilla Cihaner, Ahmet M. Önal

Polymer Chemistry, 2013, 4, 2457-2463

 

b_240_210_16777215_0___images_stories_56.phtshp2.jpgTwo new furan and benzochalcogenodiazole based monomers, namely 4,7-di(furan-2- yl)benzo[c][1,2,5]selenadiazole (FSeF) and 4,7-di(furan-2-yl)benzo[c][1,2,5]thiadiazole (FSF), were designed and synthesized via donor-acceptor-donor approach. The monomers were electrochemically polymerized via potentiodynamic or potentiostatic methods. The monomers and their polymers exhibited lower oxidation potentials (1.16 V and 1.06 V for monomers; 0.93 V and 0.80 V for polymers vs. Ag/AgCl) and red shifts of the whole dual-band absorption spectra upon moving from S to Se. Intramolecular charge transfer properties of the monomers and the polymers were demonstrated by using electroanalitical and optical methods. Also, the polymers PFSeF and PFSF were multicolored at different redox states and have low band gaps of 1.43 eV and 1.61 eV, respectively.

 

 
55-A New Processable and Fluorescent Polydithienylpyrrole Electrochrome with Pyrene Appendages

Seha Tirkes, Jetmire Mersini, Zahide Öztas, Melek Pamuk Algi, Fatih Algi, Atilla Cihaner

Electrochimica Acta, 90, 295–301, (2013)

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A new hybrid compound, namely 1-(pyren-3-yl)-2,5-di(thiophen-2-yl)-1H-pyrrole (SNS-P), was polymerized via both chemical and electrochemical methods. Chemically obtained soluble polydithienylpyrrole (c-PSNS-P) bearing pyrene appendages is a homogeneous and uniform polymer with a number averaged molecular weight of 15,200g/mol.The polymer exhibits both multi-electrochromic and fluorescent properties.Upon oxidation, the color of electrochemically obtained polymer (e-PSNS-P)changes from yellowish orange to greenish yellow and to green/blue and finally to blue. In addition, the polymer induces yellowish orange (564 nm) and brightorange emission (613 nm) in solution and solid states, respectively.

 
54. Pyrrole Coupling Chemistry: Investigation of Electroanalytic Spectroscopic and Thermal Properties of N-Substituted Poly(Bis-Pyrrole) Films

Olcay Mert, Ayhan S. Demir and Atilla Cihaner
RSC Advances, 3, 2035-2042 (2013)

An etheric member of N-linked polybispyrroles (PolybisPy) b_250_0_16777215_0___images_publications_54.jpgbased on 1-(3-(2-(2-(3-(1H-pyrrol-1-yl)propoxy)ethoxy)ethoxy)propyl)-1H-pyrrole (1) was electro-chemically synthesized for the versatile investigation of its exciting electrochromic and ion receptor properties. It has been fully characterized by electroanalytic, spectroscopic, thermal, and four-probe techniques. It was thereby found that P1 shows strong stability, and a reversible redox process as well as a good electrochromic material property; transparent yellow in the neutral state, light pink in the intermediate state, and blue in the oxidized state. Also, the corresponding polymer (P1) exhibited a selective voltammetric response towards Na+ among the alkali series in an organic medium. Moreover, P1 film was used to detect Ag+ ions in the solution by using cyclic voltammetry without precipitants or complexing ligands, and SEM images confirmed the deposition of metallic silver on the film surface. These prominent features also make P1 a good candidate for any practical uses, such as the recovery of metals and ion sensors.

 
53. Synthesis and Electro-optical Properties of New Conjugated Hybrid Polymers Based on Furan and Fluorene Units

Arzu Günes, Atilla Cihaner and Ahmet M. Önal
Electrochimica Acta, 89, 339-345 (2013)

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A novel series of hybrid monomers containing furan and fluorene units, namely 2-(2-(furan-2-yl)-9H-fluoren-7-yl)furan (FFF), 2,7-di(furan-2-yl)-9H-fluoren-9-one (FOF) and 2-(2-(furan-2-yl)-9,9-dihexyl-9H-fluoren-7-yl)furan (FHF), was synthesized and their electrochemical polymerization was achieved via potential cycling. Optical and electrochemical properties of the polymers, poly(2-(2-(furan-2-yl)-9H-fluoren-7-yl)furan (PFFF), poly(2,7-di(furan-2-yl)-9H-fluoren-9-one) (PFOF) and poly(2-(2-(furan-2-yl)-9,9-dihexyl-9H-fluoren-7-yl)furan) (PFHF), were investigated and it was found that polymer films exhibited quasi-reversible redox behavior (Epox= 0.92 V for PFFF, Epox = 1.08 V for PFOF and Epox= 0.99 V for PFHF) accompanied with a reversible electrochromic behavior, yellow to dark blue for PFFF, orange to green for PFOF and orange to green for PFHF. Their band gap values (Eg) were found to be 2.49, 2.32 and 2.61 eV for PFFF, PFOF and PFHF, respectively.

 
52. Ag nanostructures on a poly(3,4-ethylenedioxythiophene) PEDOT film prepared with electrochemical route: a controllable roughened SERS substrate with high repeatability and stability

Üzeyir Dogan, Murat Kaya, Atilla Cihaner and Mürvet Volkan
Electrochimica Acta, 85, 220-227 (2012)

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A simple, reliable and reproducible one-step electrochemical method for the preparation of surface-enhanced Raman-active polymer-mediated silver nanoparticles (Ag NPs) on planar indium tin oxide (ITO) coated glass substrates was reported. Poly(3,4-ethylenedioxythiophene) (PEDOT) film was used as a support material for dispersing nanostructured silver nanostructures on the surface homogeneously, since 3,4-ethylenedioxythiophene (EDOT) monomer polymerizes regioregularly. The optical properties and morphologies of the silver substrates have been investigated by ultraviolet–visible (UV–vis) spectroscopy and field emission scanning electron microscopy (FE-SEM). The UV–vis and FE-SEM results revealed that the Ag nanostructures separately appeared on the PEDOT coated ITO after reduction. The effect of the thickness of PEDOT polymer film, reduction potential of silver, the concentration of silver ion solution and the amount of silver particle on the polymer film on the SERS response were studied as well as repeatability and temporal stability of prepared substrates. Brilliant cresyl blue (BCB) has been used as Raman probes to evaluate the properties of the new SERS substrates. Signals collected over multiple spots within the same substrate resulted in a relative standard deviation (RSD) of 9.34%, while an RSD of 11.05% was measured in signals collected from different substrates. The SERS-active substrates were robust and stable which lost only 5.71% of initial intensity after 1 month.

 
51. A Novel Terthienyl Based Polymer Electrochrome with Peripheral BODIPY

Fatih Algi and Atilla Cihaner
Polymer, 53, 3469-3475 (2012)

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Design, synthesis and electropolymerization of a new hybrid material based on terthienyl system bearing BODIPY appendage are reported. This electrochemically polymerized unique combination readily gives an electrochromic polymer with a narrow optical band gap (1.71 eV). The electrochrome exhibits purple color when neutralized and sky blue color when oxidized in a monomer-free electrolyte solution containing 0.1 M tetrabutylammonium tetrafluoroborate dissolved in acetonitrile. Spectroscopic and electrochemical features of the electroactive polymer electrochrome indicate that it is a promising candidate for electrochromic device and display applications.

 
50. A New Highly Conductive Lithium Salt-Nonionic Surfactant Lyotropic Liquid Crystalline Mesophase and Its Application

Cemal Albayrak, Atilla Cihaner and Ömer Dag
Chemistry-A European Journal, 18, 14, 4190-4194 (2012)

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The findings suggest that any highly concentrated solution of a hydrated metal salt that has high heat of vaporization in the confined domains of the LLC mesophase is a suitable solvent for self-assembly. The LiNO3- and LiCl-containing LLC mesophases have a high resistance to evaporation and display high ionic conductivities over a broad temperature range. The LiNO3 LLC mesophase has higher ionic conductivity among the investigated LLC mesophases, but the LiCl LLC mesophases are stable at higher water concentration and may have higher ionic conductivity in dilute conditions. Moreover, the LiCl system is more stable at lower humidity. Therefore, the new lithium-containing LLC mesophase can be a good candidate as a new, cheap, and environmentally friendly electrolyte material for non-water-sensitive electrochemical applications, for which a highly conductive gel phase is required.

 
49. Members of CMY Color Space: Cyan and Magenta Colored Polymers Based on Oxadiazole Acceptor Unit

Merve Içli Özkut, Melek Pamuk Algi, Zahide Öztas, Fatih Algi, Ahmet M. Önal and Atilla Cihaner
Macromolecules, 45, 2, 729-734 (2012)

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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 cm2/C), whereas as expected ethylenedioxythiophene containing one has the lowest band gap as 1.08 eV.

 
48. Donor-Acceptor Polymer Electrochromes with Cyan Color: Effect of Alkyl Chain Length on Doping Processes

Özden Çelikbilek, Merve Içli-Özkut, Fatih Algi, Ahmet M. Önal and Atilla Cihaner
Organic Electronics, 13, 1, 206-213 (2012)

A new series of donor-acceptor-donor (D-A-D) type48.jpg compounds consisting of dialkyl substituted 3,4-propylenedioxythiophene and benzothiadiazole units were synthesized and polymerized chemically and electrochemically to investigate the effect of alkyl chain length on the doping process of the conjugated polymers. It was found that the alkyl chain length plays a key role on both doping processes and the solubility of the polymer. It is also noteworthy that this new series of D-A-D electrochromes transmit or reflect the cyan color of the Cyan-Magenta-Yellow (CMY) color space in the neutral state which can be switched to transmissive grey when oxidized.

 
47. Substituent and Heteroatom Effects on the Electrochromic Properties of Similar Systems

Merve Içli-Özkut, Jetmire Mersini, Ahmet M. Önal and Atilla Cihaner
Journal of Polymer Science Part A: Polymer Chemistry, 50, 4, 615-621 (2012)

Electrochromic polymers called poly(3,4-dihydro- 3,3-bis47.jpg ((naphthalen-1-yl)methyl)-2H-thieno[3,4-b][1,4]dioxepine) (PProDOT-Np2), poly(3,3-dibenzyl-3,4-dihydro-2H-selenopheno [3,4-b][1,4]dioxepine), and poly(3,3-dibenzyl-3,4-dihydro-2H-thieno [3,4-b][1,4]dioxepine) (PProDOT-Bz2) were synthesized electrochemically and the effect of substituents and heteroatoms on the electrochromic properties were investigated for the similar systems. All polymers show electrochromism from a colored state when neutralized to transmissive when oxidized. Although, increasing bulky size (PProDOT-Np2) causes lower coloration efficiency (CE) as well as lower optical contrast, the replacement of S atom by Se atom resulted in a lower band gap polymer with a higher CE than its thiophene analog.

 
46. A Neutral State Yellow to Navy Polymer Electrochrome With Pyrene Scaffold

Merve Içli-Özkut, Zahide Öztas, Fatih Algi and Atilla Cihaner
Organic Electronics,12, 1505–1511 (2011)

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A new pyrene based soluble polymer, namely poly(3,3-didecyl-6-(1-(3,3-didecyl-3,4- dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)pyren-6-yl)-3,4-dihydro-2H-thieno[3,4-b][1,4] dioxepine), P5, which is synthesized by both chemical and electrochemical methods, is highlighted. The polymer shows both electrochromic and fluorescent properties (the emission of yellow (545 nm) and yellowish green light (524 nm) in solid state and in THF solution, respectively). It is noteworthy that P5 has a specific optical band gap (2.2 eV) to reflect the yellow color in the neutral state. Furthermore, the optical and electrochemical features of the polymer were investigated.

 
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