Yazar "Toppare, Levent" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    Random copolymers of 1,2,3-benzotriazole and alkoxy-modified naptho[2,3-b:3,4-b′]dithiophene: Syntheses, characterization and optoelectronic properties
    (Elsevier Science Sa, 2017) Isik, Ebru; Goker, Seza; Hizalan, Gonul; Hacioglu, Serife O.; Toppare, Levent
    Naphthodithiophene is a thiophene fused naphthalene with a rigid and planar structure with extended pi-conjugation system and due its electron rich nature it has been recently employed in donor -acceptor type conducting polymers. In this study, alkoxy functionalized naphthodithiophene bearing two new random copolymers namely poly4-(5 ''-(5,6-bis(dodecyloxy)naphtho[2,1-b:3,4-b']dithiophen-2-yl)-[2,2':5',2 ''-terthiophen]-5-yl)-2-dode-cyl-7-(thiophen-2-yl)-2H-benzo[d] [1,2,3]triazole (P1) and poly4-(5 ''-(5,6-bis(dodecyloxy)naphtho[2,1-6:3,4b']dithiophen-2-yl)-[2,2':5',2 '':5 '',2 '':5',2 ''''-guinguethiophen]-5-yl)-2-dodecy1-7-(thiophen-2-yl)-2H-benzo[d] [1,2,3]triazole (P2) were synthesized via Stille coupling reaction in order to monitor the effect of thiophene and bithiophene bridge units on electrochemical and optical properties of the corresponding polymers. As the acceptor moiety in the polymer backbone electron deficient benzotriazole moiety was used. Thiophene and bithiophene units were used as pi-linkers to enhance electron delocalization through polymer chain. Via alkoxy modification, synthesized polymers were highly soluble in common solvents like THF, chloroform, chlorobenzene. Altering it bridge from thiophene bridge to bithiophene, kinetic properties of the polymers were improved. Electrochemical studies revealed that while P1 has only p-dopable nature, P2 has ambipolar character. Change of pi-bridge from thiophene to bithiophene has affected the optoelectronic properties of the polymers in a favorable manner for different application areas. The polymers exhibited low lying highest occupied molecular orbital (-5.40 eV for P1 and -5.30 eV for P2) and moderate band gaps which are 2.05 eV and 2.02 eV for P1 and P2, respectively.(C) 2017 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Syntheses and Electrochemical Characterization of Low Oxidation Potential Nitrogen Analogs of Pedot as Electrochromic Materials
    (Electrochemical Soc Inc, 2016) Hacioglu, Serife O.; Yigit, Deniz; Ermis, Emel; Soylemez, Saniye; Gullu, Mustafa; Toppare, Levent
    In this study, the electropolymerization of ethyl andmethyl substituted asymmetrical nitrogen analogs of 3,4-ethylenedioxythiophene (OEt and OMe) were synthesized, characterized and their electrochemical properties were investigated. Both polymers (POEt and POMe) were synthesized electrochemically and characterized using spectroelectrochemical technique to determine optical changes of the resulting polymer films. Electrochemical studies demonstrated that these polymers exhibited a significantly low oxidation potential compared to their analogs reported in the literature. These polymers also provided a low optical bandgap with good optical contrasts. Furthermore, multi-electrochromic properties upon different applied potentials revealed that these polymers have potential applications in electrochromic devices. As a further characterization, their dual type electrochromic devices were constructed with poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) which is transmissive in its both redox states. Devices were characterized via electrochemical and spectroelectrochemical techniques. (C) 2016 The Electrochemical Society. All rights reserved.
  • [ X ]
    Öğe
    Syntheses, electrochemical and spectroelectrochemical characterization of benzothiadiazole and benzoselenadiazole based random copolymers
    (Taylor & Francis Inc, 2016) Kutkan, Seda; Goker, Seza; Hacioglu, Serife O.; Toppare, Levent
    Three novel donor-acceptor-donor type random copolymers based on benzothiadiazole (BTh) and benzoselenadiazole (BSe) were synthesized via Pd (0) catalyzed Suzuki polycondensation reaction. The two acceptor units were coupled with electron rich moieties which are carbazole (CZ), fluorene (FL) and silafluorene (SiFL). Monomers were characterized using H-1 and C-13-NMR spectroscopy. The number and weight average molecular weights of the polymers were calculated using gel permeation chromatography (GPC). All three polymers were electrochemically and spectroelectrochemically characterized. PBThBSeCZ, PBThBSeFL and PBThBSeSiFL showed only p-dopable character and their doping/dedoping potentials were determined as 1.4V/1.2V, 1.53V/1.27V and 1.8V/1.3V, respectively. Corresponding HOMO energy levels were calculated as -5.85eV, -6.05eV and -6.15eV whereas LUMO energy levels were found to be -3.67eV, -3.84eV and -3.77eV, respectively. PBThBSeCZ had lower HOMO level and band gap than PBThBSeFL and PBThBSeSiFL due to its increased electron donating capability of nitrogen atom in carbazole unit.