73. From Narrow to Narrower: A Very Low Band Gap [1,2,5]thiadiazolo[3,4-g]quinoxaline-Based Donor-Acceptor-Donor Type Electrochromic Polymer
Gurcan Gokce, Baris Karabay, Atilla Cihaner, and Merve Icli Ozkut, Journal of The Electrochemical Society, 164 (4) G50-G53 (2017). DOI: 10.1149/2.1101704jes
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.
72. Atomistic Engineering of Chemiluminogens: Synthesis, Properties and Polymerization of 2,3-Dihydro-Pyrrolo[3,4-d]Pyridazine-1,4-Dione Scaffolds
Melek Pamuk Algi, Zahide Oztas, Seha Tirkes, Atilla Cihaner, Fatih Algi, Journal of Fluorescence, 27(2), 509-519 (2017). DOI: 10.1007/s10895-016-1978-x
Two chemiluminescent compounds containing 2,5-di(thien-2-yl)pyrrole and pyridazine units, namely 5,7-di(thiophen-2-yl)-2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione (5) and 6-phenyl-5,7-di(thiophen-2-yl)-2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione (6), were successfully synthesized and electrochemically polymerized. The compounds have chemiluminescent properties and glow in the presence of hydrogen peroxide in basic medium. The intensity of the glow can be increased dramatically by using Fe3+ ions, hemin (1.0 ppm) or blood samples (1.0 ppm) as catalyst. The compounds 5 and 6 have one well-defined irreversible oxidation peak at 1.08 V and 1.33 V vs Ag/AgCl, respectively. Electrochemical polymerization of both 5 and 6 were carried out successfully by repeating potential scanning in the presence of BF3. Et2O in an electrolyte solution of 0.1 M LiClO4 dissolved in acetonitrile. The electronic band gaps (E-g) of the polymers P5 and P6 were found to be 2.02 eV and 2.16 eV, respectively. On the other hand, the corresponding polymers are electroactive and exhibited electrochromic features.
71. Effect of furan, thiophene and selenophene donor groups on benzoselenadiazole based donor-acceptor-donor systems
Lutfiye Canan Karabay, Baris Karabay, Merve Serife Karakoy, Atilla Cihaner, Journal of Electroanalytical Chemistry, 780, 84-89 (2016). DOI: 10.1016/j.jelechem.2016.08.039
A series of the monomers called 4,7-di(furan-2-yl)benzo[c][1,2,5]selenadiazole (OSeO), 4,7-di(thiophen-2-yl)benzo[c]11,2,5]selenadiazole (SSeS) and 4,7-di(selenophen-2-yl)benzo[c][1,2,5]selenadiazole (SeSeSe) was synthesized via a donor-acceptor-donor (D-A-D) approach. Benzoselenadiazole was used as an acceptor unit and furan, thiophene and selenophene were used as donor units. The effects of chalcogen atoms (0, S, and Se) in furan, thiophene and selenophene were investigated systematically on the properties of the monomers and their corresponding polymers (POSeO, PSSeS and PSeSeSe, respectively), which were polymerized electrochemically via potentiodynamic or potentiostatic methods. The monomers OSeO, SSeS and SeSeSe exhibited low oxidation potentials of 1.15, 1.25 and 1.19 V vs. Ag/AgCl, respectively. Intramolecular charge transfer interaction between donor and acceptor units was demonstrated from the emission spectra of the monomers. Also, the optical studies showed that the ambipolar and electrochromic polymers POSeO, PSSeS and PSeSeSe have low band gaps of 1.57, 1.47 and 1.45 eV, respectively.
70. Elemental sulfur-based polymeric materials: Synthesis and characterization
Mohamed Khalifa Salman, Baris Karabay, Lutfiye Canan Karabay, Atilla Cihaner, Journal of Applied Polymer Science, 133 (28), 43655 (2016). DOI:10.1002/app.43655
New elemental sulfur-based polymeric materials called poly(sulfur-random-divinylbenzene) [poly(S-r-DVB)] were synthesized by ring opening polymerization via inverse vulcanization technique in the presence of a mixture of o-, m-, and p-diviniylbenzene (DVB) as a cross-linker. A clear yellow/orange colored liquid was obtained from the elemental sulfur melted at 160 degrees C and then by adding various amounts of DVB to this liquid directly via a syringe at 200 degrees C viscous reddish brown polymeric materials were obtained. The copolymers are soluble in common solvents like tetrahydrofuran, dichloromethane, and chloroform, and they can be coated on any surface as a thin film by a spray coating technique. The characterization of the materials was performed by using nuclear magnetic resonance, fourier transform infrared, and Raman spectroscopies. The morphological properties were monitored via scanning electron microscope technique. Thermal analysis showed that an increase in the amount of DVB in the copolymers resulted in an increase in the thermal decomposition temperature. On the other hand, poly(S-r-DVB) copolymers exhibited good percent transmittance as 50% T between 1500 and 13,000 nm in electromagnetic radiation spectrum, which makes them good candidates to be amenable use in military and surveillance cameras.
69. Effect of ring size on benzimidazole unit on electro-optical properties of donor-acceptor-donor type monomers and their polymers
Saad Al-Ogaidi, Baris Karabay, Lutfiye Canan Karabay, Atilla Cihaner, Journal of Electroanalytical Chemistry, 768, 1-10 (2016). DOI: 10.1016/j.jelechem.2016.02.028
A 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.
68. New EDOT Containing Polymers: Effect of Ring Size on the Benzımıdazole Acceptor
Emine Gul Cansu-Ergun, Ahmet M. Onal, Atilla Cihaner, Electrochimica Acta, 188i 165-174 (2016). DOI: 10.1016/j.electacta.2015.11.119
In this study, three different benzimidazole (BIm) based acceptor groups bearing cyclohexane, cycloheptane and cyclooctane rings at 2-C position of benzimidazole were synthesized and coupled with ethylenedioxythiophene (EDOT) donor units via Stille cross-coupling reaction. The resulting donor acceptor-donor (DAD) type monomers were examined in terms of their electrochemical and optical behaviors. All three monomers exhibited dual absorption bands due to their donor-acceptor pattern and exhibited one irreversible oxidation peak at about 0.80 V. The monomers were electrochemically polymerized via both potentiostatic and potentiodynamic methods and electro-optical properties of obtained conjugated polymer films were investigated in monomer free electrolytic solution. It was found that the polymer films exhibited quasi-reversible redox behavior due to the doping/dedoping process of the polymers, which was accompanied by a reversible electrochromic behavior. Electrochromic investigations showed that all three polymer films showed similar multichromic behaviors: green in the neutral state, gray in the oxidized state, and brick-red in the reduced state. Their band gap (Eg) values were elucidated utilizing spectroelectrochemical data and it was found to be around 1.18 eV. Furthermore, one of the polymer film was utilized for the construction of transmissive type electrochromic device (ECD) with poly(3,4-ethylenedioxythiophene) (PEDOT).
67. Synthesis and Characterization of New Dithienosilole Based Copolymers
Lutfiye Canan Karabay, Mohammed Al-Jumaili, Atilla Cihaner, ECS Journal of Solid State Science and Technology, 5(7) Q213-Q218 (2016). DOI: 10.1149/2.0021609jss
2-Ethylhexyl substituted dithienosilole based soluble polymers including thiophene (1) and bithiophene (2) units were synthesized via Stille coupling reaction. The presence of 2-ethylhexyl substituents on the silole ring gave solubility property to the polymers in common solvents. According to gel permeation chromatography measurements, the weight average molecular weights of the polymers 1 and 2 were found to be as 70,977 with a polydispersity index of 2.30 and 110,439 with a PDI of 1.42, respectively. Fluorescent polymers in toluene solution have maximum emisssion bands at 634 nm for the polymer 1 and 613 nm for the polymer 2. Chemical and electrochemical doping of the polymers in the solution and in the film forms were monitored by using ultraviolet-visible spectroscopic technique. The polymers exhibited chromic (chemochromic and electrochromic) properties. While the colors of the neutral polymer films are purple for the polymer 1 and reddish brown for the polymer 2, both polymers are transparent sky blue at their oxidized states. The bandgaps of polymers in film forms were calculated as 1.81 eV for the polymer 1 and 1.92 eV for the polymer 2. Also, electrochromic device applications of the polymers were done. Electrochemical and optical behaviors of the polymers demonstrated that they can be good candidates for optoelectronic applications.
66. Propylenedioxy and Benzimidazole Based Electrochromic Polymers
Emine Gul Cansu Ergun, Ahmet M. Onal, Atilla Cihaner, Journal of The Electrochemical Society, 163 (5), G53-G60 (2016). DOI: 10.1149/2.0161606jes
In this study, three acceptor units were synthesized by substituting cyclohexane, cycloheptane and cyclooctane rings at 2-C position of benzimidazole. These acceptor units were coupled with dihexyl substituted 3,4-propylenedioxythiophene (PRODOT-C6) donor segments and the resulting donor-acceptor-donor monomers were polymerized via potentiostatic and potentiodynamic methods to obtain their corresponding conjugated polymers (CP). Monomers and their polymers were investigated in terms of the ring size of the substituent on the acceptor unit and their electrochemical and optical behaviors were reported. The monomers exhibited dual absorption bands (at about 310 nm and 520 nm) due to their donor-acceptor pattern. CP films on indium tin oxide conducting substrate were investigated in a monomer free electrolytic solution. The polymer films exhibited quasi-reversible redox behavior due to doping/dedoping which was accompanied by a reversible electrochromic behavior. All three polymer films showed similar multichromic behaviors: green color in the neutral state, gray in the oxidized state, and brick-red in the reduced state. Band gap values (E-g) were elucidated via both electrochemical and optical methods. Moreover, electrochromic device (ECD) was constructed with one of the polymer films (cyclohexane ring bearing benzimidazole and PRODOT-C6 containing polymer) with poly(3,4-ethylenedioxythiophene) (PEDOT).
|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
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|
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
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
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
Melek Pamuk Algi, Atilla Cihaner, 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)
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)
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)
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)
A 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
Two 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)
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) based 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)
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)
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)
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.