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Article Citation - WoS: 21Citation - Scopus: 21Synthesis and Electro-Optical Properties of New Conjugated Hybrid Polymers Based on Furan and Fluorene Units(Pergamon-elsevier Science Ltd, 2013) Gunes, Arzu; Cihaner, Atilla; Onal, Ahmet M.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-(furan2-yl)-9,9-dihexyl-9H-fluoren-7-yl)furan) (PFHF), were investigated and it was found that polymer films exhibited quasi-reversible redox behavior (E-p(ox) =0.92V for PFFF, E-p(ox) = 1.08V for PFOF and E-p(ox) = 0.99V 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 (E-g) were found to be 2.49, 2.32 and 2.61 eV for PFFF, PFOF and PFHF, respectively. (C) 2012 Elsevier Ltd. All rights reserved.Article Citation - WoS: 18Citation - Scopus: 19Effect of Furan, Thiophene and Selenophene Donor Groups on Benzoselenadiazole Based Donor-Acceptor Systems(Elsevier Science Sa, 2016) Karabay, Lutfiye Canan; Karabay, Bads; Karakoy, Merve Serife; Cihaner, AtillaA 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. (C) 2016 Elsevier B.V. All rights reserved.Article Citation - WoS: 16Citation - Scopus: 16Synthesis and electropolymerization of thieno[3,4-c]pyrrole-4,6-dione based donor-acceptor-donor type monomers(Elsevier Science Sa, 2020) Cakal, Deniz; Cihaner, Atilla; Onal, Ahmet M.Two monomers containing thieno [3,4-c]pyrrole-4,6-dione (TP) acceptor units, namely 5-(2-ethylhexyl)-1,3-di (furan2-yl)-4H-thieno [3,4-c]pyrrole-4,6(5H)-dione (FTPF) and 5-(2-ethylhexyl)-1,3-di (selenophen-2-yl)-4H-thieno[3,4-c] pyrrole-4,6(5H)-dione (STPS), were synthesized via donor-acceptor-donor approach. Under the same template structure, the effect of heteroatom of the donor unit on redox and optical properties of the monomers and their corresponding polymers obtained via electrochemical method (PFTPF and PSTPS) were investigated. The results were also compared to their thiophene analogues 5-(2- ethylhexyl)-1,3-di (thiophen-2-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (TTPT) as the monomer and PTTPT as the polymer. Three monomers exhibited dual absorption bands one at high energy region due to the pi-pi* transition and the other one at low energy region which might be attributed to intramolecular charge transfer (ICT). An increase in ICT and a decrease both in the band gap and quantum yield was observed with increasing size of the heteroatomof the donor units. The oxidation potentials of the monomers and that of their corresponding polymer films were found to follow the order of decreasing aromatization energy from thiophene to furan (i.e thiophene > selenophene > furan). Also, heavy-atom substitution (PSTPS) effect showed itself by narrowing the optical band gap of the neutral state electrochromic polymer films: 1.90 eV for PFTPF, 1.82 eV for PTTPT and 1.76 eV for PSTPS.Article Citation - WoS: 13Citation - Scopus: 13Effect of the Donor Units on the Properties of Fluorinated Acceptor Based Systems(Elsevier Sci Ltd, 2021) Cakal, Deniz; Akdag, Akin; Cihaner, Atilla; Onal, Ahmet M.A new series of monomers in the donor-acceptor-donor array, namely 5-fluoro-4,7-di(furan-2-yl)benzo[c][1,2,5] thiadiazole (F2BT-F), and 5-fluoro-4,7-di(selenophen-2-yl)benzo[c][1,2,5] thiadiazole (S2BT-F), bearing 5-fluorobenzo[c][1,2,5]-thiadiazole as the acceptor moiety and furan and selenophene as the electron donating groups was synthesized and polymerized electrochemically. To compare heteroatom effect, thiophene analogue of newly synthesized (FBT)-B-2-F and S2BT-F namely, (5-fluoro-4,7-di(thiophen-2-yl)benzo[c][1,2,5] thiadiazole (T2BT-F)) and its corresponding polymer were also synthesized. Effect of donor units on the electrochemical and optical properties of fluorinated acceptor based systems was investigated in terms of the effect of different sized heteroatoms in five-membered rings on the dihedral angle and planarity. Theoretical calculations also suggested a deviation from planarity upon fluorination. Moreover, electrochemically obtained polymers possess low bandgap values (1.62 eV-1.68 eV for PF2BT-F and PS2BT-F, respectively) and exhibited electrochromic properties with relatively low switching times.
