Design and synthesis of novel donor-acceptor type monomers and ınvestigation of optoelectronic properties of their polymers

Ünver, Elif Köse
A proven strategy, donor-acceptor approach, to reduce the band gap of conjugated materials and possibly improve the photocurrent is to incorporate electron-rich and electron-deficient units in an alternating fashion in a polymer chain. For this purpose, a wise selection of donor and acceptor moieties in a monomer structure results in desired finishing properties of polymeric materials. In this study, fourteen novel monomers were synthesized to explore the acceptor and donor effects on the electronic and optoelectronic properties. Dibenzophenazine, dibenzopyrido]quinoxaline, tetrahydro- dibenzophenazine, thiadiazoloquinoxaline, pyrazinoquinoxaline, thienopyrazine, benzoselenadiazole, thienoselenadiazole were used as acceptor moieties, while thiophene, 3-hexylthiophene and 2,3-dihydrothienodioxine (EDOT) were used as the donor components in these donor-acceptor molecules. To synthesize desired monomers, well-known synthetic methods were performed, including bromination, nitration, reduction and condensation. Bromination was achieved by two different ways depends on the aim, NBS and Br2/HBr medium. For the nitration, HNO2 and H2SO4 were used together. Fe metal in refluxing acetic acid was used as the reducing agent in case of nitro group reductions. On the other hand, Zn metal/AcOH system was chosen for the reduction of both nitro groups and thiadiazole structure to amine, simultaneously. Finally, the Stille Coupling was used to obtain resulting acceptor-donor-acceptor monomers. These synthesized monomers were polymerized by electrochemically and investigated their properties by methods such as spectroelectrochemistry, kinetic and colorimetry studies. Spectroelectrochemistry experiments were performed in order to investigate key properties of conducting polymers such as band gap, maximum absorption wavelength, the intergap states that upon doping and evolution of polaron and bipolaron bands. Switching time and optical contrast of the polymers were evaluated via kinetic studies.


A new p and n dopable selenophene derivative and its electrochromic properties
Ardahan, Gülben; Toppare, Levent Kamil; Department of Chemistry (2008)
A novel electrically conducting polymer, poly(2-dodecyl-4,7-di(selenophen-2-yl)benzotriazole) (Poly(SBT)), containing selenophene as a strong donor and benzotriazole as a strong acceptor group was synthesized by electrochemical polymerization. Homopolymerization and copolymerization ( in the presence of 3,4-ethylenedioxythiophene (EDOT) ) was achieved in acetonitrile/ dichloromethane(95/5 v/v) with 0.1M tetrabutylammonium hexafluorophosphate (TBAPF6). The electrochemical and optical properties of homopolyme...
Synthesis and characterization of a polybenzoxazine from a difunctional amine and a trifunctional phenol
Kaya, Şafak; Tinçer, Teoman; Department of Polymer Science and Technology (2009)
Synthesis of a polymer with benzoxazine units in the main chain backbone by a trifunctional phenol, a difunctional amine, and paraformaldehyde was achieved. Thermal, mechanical and spectroscopic characterization and the viscosity properties of the synthesized polymer were studied. In the first step of this study, a fast and feasible method for the synthesis of the benzoxazine precursors was developed since some methods mentioned in the literature about the synthesis of the benzoxazine derivatives last long ...
Combination of donor characters in donor-acceptor-donor type polymers containing benzothiadiazole and quinoxaline as the acceptor units
Şendur, Merve; Toppare, Levent Kamil; Department of Chemistry (2011)
Donor-acceptor-donor approach is one of the effective ways to synthesize low band gap polymers. The monomers that will be designed with respect to donor-acceptor-donor approach have low band gap achieved by the coupling of a strong donor with high HOMO level to a strong acceptor with low LUMO level. Thus, the new donor-acceptor material will have a reduced bandgap (Eg) relative to either of its parent components. Due to this point of view, in this study, new electroactive benzothiadiazole and 2,3-bis(4-(ter...
Synthesis of conducting block copolymers and their use in the immobilization of invertase and polyphenol oxidase enzyme
Kıralp, Senem; Kıralp, Senem; Department of Chemistry (2004)
A new thiophene derivative containing menthyl group (MM) was synthesized and polymerized via chemical and electrochemical methods. Polymers obtained and MM itself were used to synthesize copolymers with pyrrole under conditions of constant potential electrolysis. Cyclic Voltammetry, thermal analysis and scanning electron microscopy analyses were performed for the characterization of samples. Immobilization of invertase and polyphenol oxidase enzymes was performed in the matrices obtained via copolymerizatio...
Development of sensitive analytical methods for thallıum determination by atomic absorption spectrometry
Arı, Betül; Ataman, Osman Yavuz; Department of Chemistry (2009)
The use of slotted quartz tube (SQT) as an atom trap in atomic absorption spectrometry (AAS) provides a more stable chemical environment for atomization; the technique is simple and easily applicable in any laboratory. This thesis study involves application of SQT together with some other approaches to thallium determination by AAS. The first stages involve the efforts to improve nebulization efficiency of conventional flame atomic absorption spectrometry (FAAS) with and without the use of SQT. This is achi...
Citation Formats
E. K. Ünver, “Design and synthesis of novel donor-acceptor type monomers and ınvestigation of optoelectronic properties of their polymers,” Ph.D. - Doctoral Program, Middle East Technical University, 2010.