Poly electrochromic devices

Ahmad S, Singh S (2008) Electrochromic device based on carbon nanotubes functionalized poly(methyl pyrrole) synthesized in hydrophobic ionic liquid medium. Electrochem Commun 10 895-898... 

Electrochromic devices using poly(3-octylthiophene) associated to vanadium oxide as cathodically colouring material and a solution of polyethylene oxide (PEO) mixed with lithium perchlorate as solid electrolyte were tested [12]. Bithiophene properties were also discussed... 

S.I. Cho, R. Xiao, and S.B. Lee, Electrochemical synthesis of poly(3,4-ethylenedioxythiophene) nanotubes towards fast window-type electrochromic devices. Nanotechnology 18, 405705 (2007). 

Compared with PEO electrolytes, PDVF, and PMMA electrolytes exhibited higher ionic conductivities. In particular, PMMA has attracted increasing attentions due to its low cost, high solvent retention ability, high transparency, and processibility. The first allpolymer electrochromic device was obtained based on a gel electrolyte and PEDOT-PSS [poly(styrene sulfonate)] electrochromic material (Argun et al., 2003). The fabricated device exhibited a maximum transmittance change of 51% at 540 nm. In addition, this device was fairly stable and only 5% contrast loss was observed after 32,000 cycles. 

Shim, G.H., Han, M.G., Sharp-Norton, J.C., Creager, S.E., Foulger, S.H., 2008. Inkjet-printed electrochromic devices utilizing polyaniline-silica and poly(3,4-ethylenedioxythiophene)-silica colloidal composite particles. J. Mater. Chem. 18,594-601. 

To improve performance, many PEDT derivatives used either alone or in combination have been proposed. While the electro-optical properties of WO3 are fixed, the colors and hue of conducting polymers may be altered by modification of the monomers. For example, Reynolds has studied the electrochromic properties of a multitude of EDT derivatives [100,109], and recently reported an all-polymer electrochromic device based on two different PEDT derivatives [110]. Depending on their chemical structure, the various PEDT derivatives exhibit different colors upon switching from the oxidized to the reduced state. For example, poly(tetradecylethylenedioxythiophene) (C14-EDT) is similar in switching to PEDT from transparent to blue, but it has an enhanced optical contrast. 

Mastragostino, M., C. Arbizzani, A. Bongini, G. Barbarella, and M. Zambianchi. 1993. Polymer-based electrochromic devices—I. Poly(3-methylthiophenes). Electrochim Acta 38 135-140. 

A number of conjugated heterocyclic polymers, viz., poly(pyrrole) [9], poly(p-phenylene) [10], poly(thiophene) [11], and poly(aniline) [12] are also electrically conducting and continue to be developed and studied for electrochromic devices [13-14 see also the companion chapter in this volume] and ion switching devices [15-16], among others. Polymer films with high electrical conductivity have been generated by electrochemical polymerization of benzenoid, nonbenzenoid and heterocyclic aromatics, in particular from the derivatives of pyrrole, thiophene, carbazole, azulene, pyrene, triphenylene and aniline. The electrochemical approach for making these films is very versatile and it provides a facile way to vary the properties of the films. The realization of the applications for each electroactive polymer depends on the control and particularly the enhancement of the... 

Self-doped polyanilines are advantageous due to properties such as solubility, pH independence, redox activity and conductivity. These properties make them more promising in various applications such as energy conversion devices, sensors, electrochromic devices, etc. (see Chapter 1, section 1.6). Several studies have focused on the preparation of self-doped polyaniline nanostructures (i.e., nanoparticles, nanofibers, nanofilms, nanocomposites, etc.) and their applications. Buttry and Tor-resi et al. [51, 244, 245] prepared the nanocomposites from self-doped polyaniline, poly(N-propane sulfonic acid, aniline) and V2O5 for Li secondary battery cathodes. The self-doped polyaniline was used instead of conventional polyaniline to minimize the anion participation in the charge-discharge process and maximize the transport number of Li". In lithium batteries, it is desirable that only lithium cations intercalate into the cathode, because this leads to the use of small amounts of electrolyte... 

A. S. Ribeiro, D. A. Machado, P. F. D. Filho, M. A. De Paoli, Solid-state electrochromic device based on two poly(thiophene) derivatives, Journal of Electroanalytical Chemistry 2004, 567, 243. 

Many typical electrochromic devices are composed of seven layers, as shown in Figure 20.4 [37]. One alternative to this classical model is a simplified five-layer electrochromic device, where transparent conducting layers were eliminated by Mecerreyes et al. (Figure 20.5) [37]. This type of configuration was successfully tested by using a solution of poly(ethylene oxide-lithium triflate) (PEO -I- CEsSOsLi) in tetrahydrofuran (THF) as a polymer electrolyte, while PEDOT was used as an electroactive polymer by Carpi and De Rossi [29]. 

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],... 

A new alkylenedioxythiophene derivative, spirobipropylenedioxythiophene [poly(spiroBiProDOT)], was reported by Reeves et al., which exhibited three color states and a luminance change of 30 % at intermediate potentials, leading to electrochromic devices with greater stability and longer lifetimes (Figure 20.11) [61]. 

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