Polythiophene and its derivatives

ODNs appeared, and stable complexes were formed. PEDOT was first prepared by electropol5mierization at the surface of GCE, and then a DNA solution was spread over the pol5mier-modified electrode [98]. DNA was available for the electrostatic binding of Nile blue as redox indicator. The composite electrode showed electrocatal3d ic properties toward the reduction of hydrogen peroxide. 

In the area of molecular technology, a switch based on two orthogonaUy fused polymer chains, one doped (conductive) and the other tmdoped (insulating) has been proposed, and an oUgomer has been synthesiz Many tasks remain here, such as incorporation of this unit into a device of molecular dimensions and discovering a way to actively switch the unit 

Model for two orthogonidly fused conductive polymer chains. An 

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Rudge et al. believe that polythiophene and its derivatives are suitable materials for type HI supercapacitors. Especially, the electrochemically prepared poly-... 

A major goal of the research on conducting polymers has been the development of a rechargeable plastic battery. Cells based on polypyrrole and lithium electrodes have been developed in which the energy per unit mass and discharge characteristics are comparable to nickel-cadmium cells. Current interest appears to center around stable, processable polymers, such as polythiophene and its derivatives, and polyaniline. 

Oxide, flouride, and polymeric films, as well as certain others, are used as protective coatings for HTSC materials (for example, see [505]). The electrodeposition of conducting polymers such as polypyrrole [433,491, 493, 506], polythiophene and its derivatives [493, 507], and polyaniline [478] is the most effective process. Anodic electropolymerization in acetonitrile solutions proceeds without any degradation of the HTSC substrate and ensures continuous and uniform coatings. Apparently, this method is promising not only for the fabrication of compositions with special properties based on HTSC [50, 28,295] as mentioned above, but also for the creation of junctions with special characteristics [507]. 

The performance of OFETs has continuously improved since they were first reported in 1987 [8, 9]. The rate of the progress can be visualized in Figure 14-13, where we have plotted the field-effect mobility of five prominent organic com-pounds as a lunclion of the publication date. The data include one polymer, polythiophene and its derivatives and four small molecules (three oligothiophenes, plus pentacene). Note that the highest mobility of small molecules was reported on single crystals. 

S.Hotta, M.Soga and N.Sonoda, Novel organometallic routes to polythiophene and its derivatives, Synth. Met., 26 267 (1988). 

Tourillon, G. 1986. Polythiophenes and its derivatives. In Handbook of conducting polymers, ed. T.A. Skotheim. New York Marcel Dekker, p. 294. 

Poly (thiophene)s are of particular interest as electfochromic materials owing to their chemical stability, ease of synthesis and processability. For the most part, current research has been focused on composites, blends and copolymer formations of several conjugated polyheterocyclics, polythiophene and its derivatives, especially PEIX)T. In one example, poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(2-acrylamido-2-methyl-l-propanesulfonate) (PAMPS) composite films were prepared by Sonmez et al. for alternative electrochromic applications [50]. Thin composite films comprised of PEDOT/PAMPS were reported to switch rapidly between oxidized and neufial states, in less than 0.4 s, with an initial optical contrast of 76% at A.max. 615 nm. Nanostructured blends of electrochromic polymers such as polypyrrole and poly(3,4-ethylenedioxythiophene) were developed via self-assembly by Inganas etal. for application as an electrochromic window [26]. Uniir etal. developed a graft-type electrochromic copolymer of polythiophene and polytetrahydrofuran for use in elecfiochromic devices [51]. Two EDOT-based copolymers, poly[(3,4-ethylenedioxythiophene)-aZ/-(2,5-dioctyloxyphenylene)] and poly[(3,4-ethylenedioxythiophene)-aft-(9,9 -dioctylfluorene)] were developed by Aubert et al. as other candidates for electrochromic device development [52],... 

Polythiophenes and their derivatives have been intensely studied due to their interesting electronic properties. Owing to the combination of their electronic properties, environmental stability, stmctural versatility, low bandgap, low cost and ease of preparation, polythiophene and its derivatives have been utilized in the development of many new electrochromic devices. Here, we focus on the use of polythiophenes for electrochromic applications in terms of their basic properties bandgap and its relation to stability, chain length of substituted functional groups and optical properties such as electrochromic contrast (with some examples from the literature). 

Potential applications of polythiophene and its derivatives in the Aelds of conductors, organic batteries, and display devices are greatly impeded by their high reactivity toward oxygen and moisture, which requires constrained experimental conditions such as an argon-controlled atmosphere and a highly puriAed medium [75]. Two techniques have been used to synthesize polythiophene and its derivatives chemical and electrochemical procedures. A chemically synthesized polymer is... 

Tourillon G (1986) Polythiophene and its Derivatives. In Skotheim TA (ed) Handbook of Conducting Polymers. Marcel Dekker, New York, p 293... 

Polythiophene and its derivatives show remarkable air stability in both oxidized and reduced form [111]. However, there are variable reports on their stability in different types of enviromnents. The ionization potential of poly thiophene is estimated to be above 5 eV, which is high enough to protect the polymer from forming a charge-transfer complex with otygen to cause oxidative instability. Both electrochemically as-prepared polythiophene and polythiophene redoped after ammonia compensation showed much better air stability compared to polyacetylene [112,113]. 

Polythiophene and its derivatives can be polymerized by chemical or electrochemical techniques. In this study, the electrochemical method was utilized.The mechanism is a cationic radical polymerization 11). The polymerization pathway can be summarized in the following steps 1) oxidation of the monomer to form a radical cation, 2) dimerization of the radical cations, 3) loss of proton to yield a neutral dimer, 4) oxidation of dimer to form a radical cation, 5) reaction of dimer radical cation with another radical cation, 6) repeat of the this study, are 3-methylthiophene, tetrabutylammonium tetrafluoroborate (TBATFB), as the supporting electrolyte. The organic solvent was acetonitrile. The resulting polymer was the first conducting polymer family found to be stable in air and water in both their doped or undoped state. 

Figure 6. (a) Absorption spectra of polythiophene and its derivatives substituted with normal-alkyl... 

Polythiophene and its derivatives are characterized as p-type semiconductors, and so they are expected to form a Schottky-like junction with a metal having low work function [98]. In this case the charge injection over this metal/polymer interface plays an important role. The charge injection mechanism can be studied by measuring temperature and voltage dependence of current. 

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