Browsing by Author "Cihaner, Atilla"

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Citation - WoS: 13
Citation - Scopus: 13
[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; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
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
Acid/ Base Doped/ Dedoped Low Band Gap Polymer
(Amer Chemical Soc, 2016) Karabay, Baris; Gokce, Gurcan; Cihaner, Atilla; Icli Ozkut, Merve; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
[No Abstract Available]
Citation - WoS: 11
Citation - Scopus: 12
Ag Nanostructures on a Poly(3,4-Ethylenedioxythiophene) Film Prepared With Electrochemical Route: a Controllable Roughened Sers Substrate With High Repeatability and Stability
(Pergamon-elsevier Science Ltd, 2012) Dogan, Uzeyir; Kaya, Murat; Cihaner, Atilla; Volkan, Murvet; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
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. (C) 2012 Elsevier Ltd. All rights reserved.
Citation - WoS: 45
Citation - Scopus: 45
An Ambipolar Low Band Gap Material Based on Bodipy and Edot
(Elsevier Science Bv, 2009) Algi, Fatih; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
A novel donor-acceptor type conducting polymer based on BODIPY dye as acceptor and EDOT units as donor parts is synthesized electrochemically. The unique combination of BODIPY and EDOT units provides an ambipolar (n- and p-doping processes) low band gap material (4). This is the first example of p-n junction in an organic pi-conjugated material where BODIPY unit is incorporated directly in the main chain. Furthermore, the polymer film exhibits electrochromic behavior upon p-doping: a color change from light violet (neutral) to indigo (oxidized). (C) 2009 Elsevier B.V. All rights reserved.
Citation - WoS: 33
Citation - Scopus: 34
An ambipolar neutral state green polymeric electrochromic
(Elsevier, 2009) Algi, Fatih; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
The synthesis and properties of highly stable neutral state green polymeric electrochromic, P1, which is based on 5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,3-di(1H-pyrrol-2-yl)quinoxaline were highlighted. P1 exhibits three well-defined absorption bands with a narrow band gap (1.17 eV). The n- and p-doping (ambipolar) processes suggest that P1 is one of the most promising neutral state green polymers and it can be used in supercapacitors as either cathode or anode electrode material. Apart from the stability and the robustness of the polymer film, P1 shows multi-electrochromic behavior; gray-purple in the reduced form and highly transmissive blue color in the oxidized state. (C) 2009 Elsevier B.V. All rights reserved.
Amin boranın hidrolitik dehidrojenlenmesinde kullanılmak üzere silika kaplı kobalt ferrit manyetik parçacıklar üzerine tutturulmuş bimetalik paladyum-bakır nanoparçacıkların hazırlanması ve karakterizasyonu
(2015) Al-aqbı, Talaat Hıkmat Hashım; Kaya, Murat; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Metal nanoparçacıklar, son on yılda katalitik sistemlerde arzu edilen uygulamaları nedeniyle oldukça dikkat çekmiştir ve bu parçacıkların bu tür sistemlerde kullanılması homojen ve heterojen katalizörler arasında köprü görevi yapmasını, diğer bir deyişle, yarı-homojenimsi (ya da çözünür heterojen) sistemlerinin oluşturulabilmesi için umut verici olarak düşünülmektedir. Çıplak nanoparçacıklar yüksek yüzey enerjileri nedeniyle kararlı değillerdir ve katalitik dönüşüm gerçekleşirken koagüle olmaya meyillidirler. Öte yandan, filtrasyon teknikleri 100 nm'den daha küçük çapa sahip olan nanoparçacıklarını ayırmada yeterli olmamaktadır. Bu koşullar altında, pahalı ultrasantrifüj yöntemi, ürün ve katalizörü ayırmak için tercih edilmektedir. Çıplak nanoparçacıkların dezavantajlarını ortadan kaldırmak, kararlılıklarını geliştirmek, ve yeniden kullanılabilir katalizörler elde etmek için, nanoparçacıkların inorganik destek üzerinde immobilizasyonu katalitik verim için istenilen özellikleri sağlar. Yüksek hidrojen depolama kapasitesi (19.6 % wt) ve düşük molekül kütlesi sayesinde, ammonyak boranın (NH3BH3) hidrolitik dehidrojenlenmesi için nanokompozit katalizörlerde yapılan yenilikler, bu katalizörlerin katı hidrojen taşıyıcısı olarak kullanılabilmesi için gereklidir. Bu tezde, ıslak emdirme yöntemiyle, silika kaplı manyetik parçacıklar üstünde desteklenen paladyum ve bakır bimetalik nanoparçacıklarını içeren yeni ve tekrarlanabilir katalizör sistemi hazırlanmıştır. Pd2+ ve Cu2+ iyonlarının silika kaplı kobalt ferrit nanoparçacıklarına eklenmesinden sonra, NH3BH3 ile birlikte Pd2+ ve Cu2+ iyonlarının silika kaplı manyetik nanoparçacıkların yüzeyinde, yerinde indirgenmesi sonucunda istenilen nanoparçacıklar elde edilir. Nanokompozit katalizörlerin karakterizasyonu indüktif olarak eşleşmiş plazma optik emisyon spektrometresi (ICP-OES), X-ışını kırınımı (XRD), X-ışını fotoelektron spektroskopisi (XPS), geçirimli elektron mikroskobu (TEM), yüksek çözünürlüklü- geçirimli elektron mikroskobu (HR-TEM) ve N2 adsorpsiyon–desorpsiyon teknikleri ile yapılmıştır. Silika kaplı kobalt ferrit (PdCuNPs/SiO2-CoFe2O4) parçacıkları üstünde desteklenen paladyum-bakır bimetalik nanoparçacıkları, oda sıcaklığında, başlangıçta 238 dk-1'lik çevrim frekansı sağlar, bu değer hem soy metal olmayan katalizörlere hem de soy metal içeren, ammonyak boranın hidrolitik dehidrojenlenmesi tepkimesinde kullanılan homojen ve heterojen katalizörlere göre daha yüksek katalitik aktiviteye sahip olduğunu gösterir. Bu katalizör sistemlerinin en önemli avantajlarından biri, katalizörün mıknatıs yardımıyla reaktör duvarında toplanabilmesi ve sürdürülebilir katalitik aktivite özelliği sayesinde, 5 defaya kadar geri dönüşümünün olması, bu katalizörün mükemmel bir şekilde yeniden kullanılabileceğini gösterir.
Citation - WoS: 6
Citation - Scopus: 6
Anodic Oxidation of N-Substituted Dipyrrolyl Linked by Polyether Bridge
(Taylor & Francis inc, 2006) Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Electroactive polymer containing polyether pseudo-cages has been synthesized by anodic oxidation of 1,11-bis(1,1-pyrrole)-3,6,9-trioxaundecane (I) using acetonitrile (ACN) as solvent and tetrabutylammonium perchlorate (TBAClO 4 ) as supporting electrolyte. Electrochemical behavior of monomer I and its polymer, poly-I , were studied using cyclic voltammetry (CV) and UV-VIS spectroscopic techniques. Also, a doping/dedoping study was carried out using electron spin resonance (ESR) and UV-VIS spectroscopic techniques. Thermal behavior of the product was studied using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA).
Citation - WoS: 7
Citation - Scopus: 8
Anodic Polymerization of 2,5-Di in Ethanol
(Pergamon-elsevier Science Ltd, 2007) Icli, Merve; Cihaner, Atilla; Cihaner, Atilla; Oenal, Ahmet A.; Cihaner, Atilla; Chemical Engineering; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Poly(2,5-di-(2-thienyl)-furan) (PSOS) was synthesized via anodic polymerization of 2,5-di-(2-thienyl)-furan (SOS) in ethanol solution containing 0.2 M LiClO4 as supporting electrolyte. The electrochemical and spectroelectrochemical properties were investigated using electroanalytical and UV-vis spectroscopic techniques, respectively. The band gap of the polymer film was found as 2.22 eV and the film was successfully switched between black oxidized state and orange neutral state. Fluorescence and electrochemical impedance spectroscopy (EIS) studies were also performed. (C) 2007 Elsevier Ltd. All rights reserved.
Citation - WoS: 13
Citation - Scopus: 15
Atomistic Engineering of Chemiluminogens: Synthesis, Properties and Polymerization of 2,3-Dihydro Scaffolds
(Springer/plenum Publishers, 2017) Algi, Melek Pamuk; Tirkeş, Seha; Oztas, Zahide; Cihaner, Atilla; Tirkes, Seha; Cihaner, Atilla; Algi, Fatih; Tirkeş, Seha; Cihaner, Atilla; Chemical Engineering; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
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.
Benzotellurodiazol Esaslı Yeni Anorganik-organik Melez Elektroaktif Monomerlerin Sentezi
(2017) Cihaner, Atilla; Işık, Murat; Algı, Fatih; 01. Atılım University
Bu çalışmada benzotelluradiazol ve benzimidazol birim esaslı altı farklı elektron verici-alıcı- verici (V-A-V) monomerin sentezi, karakterizasyonu ve polimerizasyonu rapor edilmeye çalışılmıştır. Benzotelluradiazol esaslı V-A-V monomerleri başarı ile sentezlenememiş olsada benzimidazole esaslı V-A-V monomerleri başarılı bir biçimde sentezlenmiş, karakterize edilmiş ve elektrokimyasal olarak polimerleştirilmiştir. Benzotiyadiazol ve benzoselenadiazol türevleri gibi, tiyofen ve 3,4-alkilendioksitiyofen elektron verici birimleri ile birleştirilmiş benzimidazole birimleri içeren polimerler 1.50 eV ve 1.57 eV aralığında dar band aralığı değerlerine sahip olup dışarıdan uygulanan potensiyel altında elektrokromik özellikler göstermiştir. Diğer bir taraftan benzotelluradiazol türevleri için daha önceden literatürde rapor edilen sentez reçeteleri bu çalışmadaki benzotelluradiazol esaslı V-A-V monomerlerinin sentezinde çalışmamıştır. Malesef literatürde benzotiyadiazol veya benzoselenadiazol içerikli polimerlerin benzotelluradiazol içerikli polimerlerin dönüşümünde kullanılan sentez reçeteleri monomer ve oligomer sentezlerinde çalışmamıştır. Bunun yanında teorik çalışmalar benzotelluradiazol esaslı V-A-V tipi monomerlerin ve oligomerlerin oda sıcaklığında kararlı bileşikler olduğunu ve diğer elektron alıcı benzerleri ile karşılaştırıldığında daha düşük band aralıklı polimerler verebileceğini göstermiştir. Sonuç olarak benzotelluradiazol esaslı monomerler sentezleyebilmek için bilinen sentez reçetelerinin dışında yeni stratejilerin ve reçetelerin uygulanması gerekmektedir. Bu konu üzerindeki çalışmalar sürmektedir.
Citation - WoS: 61
Citation - Scopus: 72
A Blue To Highly Transmissive Soluble Electrochromic Polymer Based on Poly(3,4-Propylenedioxyselenophene) With a High Stability and Coloration Efficiency
(Royal Soc Chemistry, 2011) Ozkut, Merve Icli; Atak, Samed; Onal, Ahmet M.; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
The optical and electrochemical properties of a regioregular and soluble alkylenedioxyselenophene-based electrochromic polymer, namely poly(3,3-didecyl-3,4-dihydro-2H-selenopheno[3,4-b][1,4] dioxepine (PProDOS-C-10), which is synthesized by electrochemical polymerization, are highlighted. It is noted that this unique polymer has a low band gap (1.58 eV) and is exceptionally stable under ambient atmospheric conditions. Polymer films retain 97% of their electroactivity after 40 000 cycles. The percentage transmittance of a PProDOS-C10 film was found to be 56.4% at 638 nm and 55.8% at 700 nm. Furthermore, this novel soluble PProDOS-C10 polymer shows an electrochromic behavior: a color change from pure blue to a highly transparent state in a low switching time (1.0 s) during oxidation, with high coloration efficiencies (328 cm 2 C-1 at 638 nm and 319 cm(2) C-1 at 700 nm) when compared to its thiophene analogue.
Citation - WoS: 2
Citation - Scopus: 2
D-A Type Conjugated Polymers in Dual Electrochromic Devices Tuning From Green To Blue Colors
(Elsevier Science Sa, 2023) Ozkut, Merve Icli; Onal, Ahmet M.; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
In this study, the electrochemical and electro-optical properties of four different dual electrochromic devices were unraveled. In all devices, soluble donor-acceptor-donor (D-A-D) type conjugated electrochromic polymers based on didecyl substituted 3,4-propylenedioxythiophene and heterodiazole analogs were used, and they were coated on ITO electrochemically for the construction of the electrochromic devices. Because all D-A-D polymers and PEDOT are colorful in their neutral states and colorless in their oxidized states, it is possible to observe one -to-one colors of pure two polymers in their electrochromic devices rather than a mixture of colors. It was observed that devices changed their colors from the tunes of green to blue under applied external voltage. Switching times, coloration efficiencies and stabilities of the electrochromic devices were calculated as ranging from 1.0 to 6.0 s, 133-544 cm2/C and 54-91 %, respectively, after 5000 cycles. The P(PSeP-C10)-P(PNP-C10) device showed the highest coloration efficiency (544 cm2/C) as well as the best optical and electrochemical stabilities among the electrochromic devices after 5000 cycles (91 % and 92 %, respectively).
Citation - WoS: 19
Citation - Scopus: 18
Design and Synthesis of New 4,4′-Difluoro Based Electrochromic Polymers
(Pergamon-elsevier Science Ltd, 2013) Algi, Melek Pamuk; Tirkes, Seha; Ertan, Salih; Ergun, Emine Gul Cansu; Cihaner, Atilla; Algi, Fatih; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
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 P2 can be switched from transmissive pink color when neutralized to transmissive blue color when oxidized. (C) 2013 Elsevier Ltd. All rights reserved.
Citation - WoS: 7
Citation - Scopus: 9
Design, Synthesis, Photochromism and Electrochemistry of a Novel Material With Pendant Photochromic Units
(Pergamon-elsevier Science Ltd, 2014) Algi, Melek Pamuk; Cihaner, Atilla; Algi, Fatih; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
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 I 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 I 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. (C) 2014 Elsevier Ltd. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 4
Designing a Solution Processable Poly(3,4-Ethylenedioxyselenophene) Analogue
(Amer Chemical Soc, 2018) Ertan, Salih; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
A new derivative (EDOS-POSS) of 3,4-ethylenedioxyselenophene integrated with alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage was synthesized and characterized. The electroactive monomer was successfully polymerized via both chemical and electrochemical methods. The obtained polymer called PEDOS-POSS was solution-processable and soluble in common organic solvents like tetrahydrofuran, toluene, dichloromethane, and chloroform. PEDOS-POSS polymer exhibited electrochromic behavior: pure blue when neutralized and highly transparent when oxidized. When compared to the parent PEDOS (1.40 eV with lambda(max) = 673 nm), PEDOS-POSS polymer film has a somewhat higher band gap (1.50 eV with lambda(max) = 668 and 724 nm). Also, PEDOS POSS exhibited high optical contrast ratio (59%) and coloration efficiency (593 cm(2)/C for 95% switching) with a low switching time (0.7 s) due to the presence of POSS cage in the polymer backbone. In addition, PEDOS-POSS polymer film was highly robust and stable under ambient conditions (without purging the electrolyte solution with inert gas). Polymer films demonstrated high electrochemical stability; for example, it retained 76% of its electroactivity after 5000 cycles. Furthermore, the polymers exhibited fluorescent properties and exhibited a reddish orange emission centered about at 640 nm. Based on the findings, to the best of our knowledge, it can be concluded that the polymers are the first examples of soluble and fluorescent PEDOS derivatives. These promising properties make PEDOS-POSS polymer a potential material for bioapplications like imaging the cancer cells as well as optoelectronic applications.
Citation - WoS: 36
Citation - Scopus: 35
A Diverse-Stimuli Responsive Chemiluminescent Probe With Luminol Scaffold and Its Electropolymerization
(Wiley-v C H verlag Gmbh, 2010) Asil, Demet; Cihaner, Atilla; Algi, Fatih; Onal, Ahmet M.; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
A diverse-stimuli responsive chemiluminescent system, SNS-Lum, and its electropolymerization to give PSNS-Lum, which is the first example of conjugated polymers with pendant luminol arms inducing chemiluminescence in the presence of super oxide radical anion under neutral conditions, are highlighted.
Citation - WoS: 27
Citation - Scopus: 31
Donor-acceptor polymer electrochromes with cyan color: Effect of alkyl chain length on doping processes
(Elsevier, 2012) Celikbilek, Ozden; Icli-Ozkut, Merve; Algi, Fatih; Onal, Ahmet M.; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
A new series of donor-acceptor-donor (D-A-D) type 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 transmits or reflects the cyan color of the Cyan-Magenta-Yellow (CMY) color space in the neutral state which can be switched to transmissive grey when oxidized. (C) 2011 Elsevier B.V. All rights reserved.
Citation - WoS: 142
Citation - Scopus: 157
Donor-Acceptor Polymer Electrochromes With Tunable Colors and Performance
(Amer Chemical Soc, 2010) Icli, Merve; Pamuk, Melek; Algi, Fatih; Onal, Ahmet M.; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
To demonstrate the effect of donor (D) and acceptor (A) units on the structure property relationships of electrochromic polymers, design, synthesis, characterization and polymerization of a series of D A type systems, 1-5, based on thiophene, 3,4-ethylenedioxythiophene, and 3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine as D units and 2,1,3-benzoselenadiazole, 2,1,3-benzothiadiazole and 2-decyl-2H-benzo[d][1,2,3]triazole as A units are highlighted. It is found that these units play key roles on the redox behavior, band gap, neutral state color, and the electrochromic performance (stability, optical contrast, coloration efficiency, and switching time) of the system. It is noted that electropolymerization of these D-A systems provides processable low band gap electrochromes, P1-P5, exhibiting high redox stability, coloration efficiency, transmittance and/or contrast ratio and low response time. Furthermore, P1-P5 reflect various hues of blue and green pallets of the RGB color-space in the neutral state. In particular, it is noteworthy that P5 is an excellent blue-to-colorless polymeric electrochrome, which, to our best knowledge, exhibits the highest optical contrast and coloration efficiency among the D A type systems. The panoramic breadth of the neutral state colors and intriguing features of these polymeric materials further confirm that D A approach allows engineering tunable electrochromes, which hold promise for commercialization of polymeric ROB electrochromics.
Donör-akseptör Düzeninde Yeni Bir Bileşik Grubununtasarımı, Sentezi ve İletken Polimerlerinin Uygulama Alanları
(2011) Cihaner, Atilla; Tirkeş, Seha; Atak, Samed; 01. Atılım University
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Citation - WoS: 29
Citation - Scopus: 31
Effect of Fluorine Substituted Benzothiadiazole on Electro-Optical Properties of Donor-Acceptor Type Monomers and Their Polymers
(Elsevier Sci Ltd, 2020) Cakal, Deniz; Ercan, Yunus Emre; Onal, Ahmet M.; Cihaner, Atilla; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
A series of trimeric monomers bearing thiophene donor units and fluorinated analogues of benzothiadiazole acceptor units was synthesized via donor-acceptor-donor approach and polymerized electrochemically in order to investigate the effect of fluorine atom on electro-optical properties of both monomers and their corresponding polymers. All monomers exhibited solvatochromic and fluorescent properties. The introduction of fluorine atom into the conjugated backbone increased the oxidation potentials. Upon moving from nonfluorinated to fully fluorinated analogues, the oxidation potential shifts anodically from 1.30 V to 1.7 V. As in the case of monomers, the fluorine atom substitution also resulted in a decrease in the HOMO energy level of the corresponding polymers, leading to an increase in the electrochemical band gap energy (1.71-1.97 eV). This result can be attributed to deviations from planarity and also to decrease in the effective conjugation length. The polymeric film also exhibited electrochromic properties under various external potentials. Switching time and coloration efficiency values decreased with increasing number of fluorine atom substitution.