Enhancing electrochromic properties of conducting polymers via copolymerization: Copolymer of 1‐(4‐fluorophenyl)‐2,5‐di(thiophen‐2‐yl)‐1H‐pyrrole with 3,4‐ethylene dioxythiophene

A copolymer of 1‐(4‐fluorophenyl)‐2,5‐di(thiophen‐2‐yl)‐1H‐pyrrole (FPTP) with 3,4‐ethylene dioxythiophene (EDOT) was electrochemically synthesized and characterized. While poly(FPTP) (P(FPTP)) has only two colors in its oxidized and neutral states (blue and yellow), its copolymer with EDOT has five different colors (purple, red, light gray, green, and blue). Electrochromic devices based on P(FPTP‐co‐EDOT) and poly(3,4‐ethylenedioxythiophene) (PEDOT) were constructed and characterized. The oxidized state of the device shows blue color whereas it shows purple for the reduced state. At several potentials the device has good transparency with green and gray colors. Maximum contrast (Δ%T) and switching time of the device were measured as 23% and 1.1 s at 555 nm. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4496–4503, 2007     

Copolymerization of Azobenzene-bearing Monomer and 3,4-Ethylenedioxythiophene(EDOT): Improved Electrochemical Performance for Electrochromic Device Applications

In this study,novel electrochromic copolymers of 3,4-ethylenedioxythiophene(EDOT)and(E)-1,2-bis(2-fluoro-4-(4-hexylthiophen-2-yl)phenyl)diazene(M1)with different monomer feed ratios were designed and synthesized electrochemically.Electrochemical and spectroelectrochemical characterizations were performed using voltammetry and UV-Vis-NIR spectrophotometry techniques to test the applicability of copolymers for electrochromic applications.In terms of electrochemical behaviors,addition of an electron-rich EDOT unit into the azobenzenecontaining copolymer increased the electron density on the polymer chain and afforded copolymers with very low oxidation potentials at around0.30 V.While the homopolymers(P1 and PEDOT)exhibited neutral state absorptions centered at 510 and 583 nm,EDOT-bearing copolymers showed red shifted absorptions compared to those of P1 with narrower optical band gaps.In addition,the poor optical contrast and switching times of azobenzene-bearing homopolymer were significantly improved with EDOT addition into the copolymer chain.As a result of the promising electrochromic and kinetic preperties,Co P1.5-bearing single layer electrochromic device that works between purple and light greenish blue colors was constructed and characterized.     

Modification of indium-tin oxide electrodes with thiophene copolymer thin films: optimizing electron transfer to solution probe molecules

We describe the modification of indium-tin oxide (ITO) electrodes via the chemisorption and electropolymerization of 6-{2,3-dihydrothieno[3,4-b]-1.4-dioxyn-2-yl methoxy}hexanoic acid (EDOTCA) and the electrochemical co-polymerization of 3,4-ethylenedioxythiophene (EDOT) and EDOTCA to form ultrathin films that optimize electron-transfer rates to solution probe molecules. ITO electrodes were first activated using brief exposure to strong haloacids, to remove the top approximately 8 nm of the electrode surface, followed by immediate immersion into a 50:50 EDOT/EDOTCA co-monomer solution. Potential step electrodeposition for brief deposition times was used to grow copolymer films of thickness 10-100 nm. The composition of these copolymer films was characterized by solution depletion studies of the monomers and atomic force microscopy (AFM), X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy (reflection-absorption infrared spectroscopy (RAIRS)) of the product films. The spectroscopic data suggest that the composition of the copolymer approaches 80% EDOTCA when electropolymerization occurs from concentrated (10 mM) solutions. AFM characterization shows that electrodeposited poly(EDOT)/poly(EDOTCA) (PEDOT/PEDOTCA) films are quite smooth, with texturing on the nanometer scale. RAIRS studies indicate that these films consist of a combination of EDOTCA units with noninteracting -COOH groups and adjacent hydrogen-bonded -COOH groups. The EDOTCA-containing polymer chains appear to grow as columnar clusters from specific regions, oriented nearly vertically to the substrate plane. As they grow, these columnar clusters overlap to form a nearly continuous redox active polymer film. ITO activation and formation of these copolymer films enhances the electroactive fraction of the electrode surface relative to a nonactivated, unmodified "blocked" ITO electrode. Outer-sphere solution redox probes (dimethylferrocene) give standard rate coefficients, kS > or = 0.4 cm.s-1, at 10 nm thick copolymer films of PEDOT/PEDOTCA, which is 3 orders of magnitude greater than that on the unmodified ITO surface and approaches the values for kS seen on clean gold surfaces.     

Synthesis of highly conductive EDOT copolymer films via oxidative chemical in situ polymerization

Poly(3,4‐ethylenedioxythiophene)s (PEDOT) represent a class of conjugated polymers that can be potentially used as an electrode material for flexible organic electronics due to their superior conductivity and transparency. In this study, we demonstrate that the conductivity of a PEDOT containing copolymer film can be further enhanced by the oxidative chemical in situ copolymerization of a liquid film spun coated from monomer mixture (3,4‐ethylenedioxythiophene (EDOT) and 3‐thienyl ethoxybutanesulfonate (TEBS)), oxidant (iron(III) p‐toluenesulfonate (Fe(OTs)₃)), weak base (imidazole), and solvent (methanol). We investigated that the effect of the processing parameters such as the molar ratios TEBS/EDOT, IM/EDOT, and Fe(OTs)₃/EDOT on the surface morphology, optical property, and the conductivity of the resulting copolymer films. These parameters have been optimized to achieve conductivities for the copolymer films as high as 170 S/cm compared with a conductivity of 30 S/cm for the pure PEDOT film synthesized using the same fabrication method. This conductivity enhancement for the copolymer films was found to be resulted from the fact that the addition of TEBS monomer reduces the copolymerization rate, leading to the formation of much more uniform film surface without defects and copolymers of higher molecular weight which increase the conductivity of the resulting copolymer film. The composition of two monomers in the copolymer film is not related to the variation of conductivity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1662–1673, 2008     

Electrochromic Properties of ‘Trimeric' Thiophene‐pyrrole‐thiophene Derivative Grown from Electrodeposited 6‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)hexan‐1‐amine and its Copolymer

A centrosymmetric polymer precursor, namely 6‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)hexan‐1‐amine (TPHA), was synthesized via a Knorr–Paal reaction using 1,4‐di(2‐thienyl)‐1,4‐butanedione and hexane‐1,6‐diamine. The resultant monomer was characterized by Nuclear Magnetic Resonance (¹H‐NMR). Electroactivity of TPHA was investigated via cyclic voltammetry. The electronic structure and the nature of electrochromism in P(TPHA) and its copolymer with EDOT, (P(TPHA‐co‐EDOT)), were examined via spectroelectrochemistry studies. P(TPHA) switches between claret red neutral state and blue oxidized state. Optical response times for coloring and bleaching processes of the P(TPHA) and P(TPHA‐co‐EDOT) were found as 2.1 s and 1.6 s, respectively.

The copolymer of TPHA was used to construct dual type polymer electrochromic devices (ECDs) against poly(3,4‐ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry and electrochromic switching out of the devices were investigated.     

A platform to synthesize a soluble poly(3,4‐ethylenedioxythiophene) analogue

Alkyl‐substituted polyhedral oligomeric silsesquioxane (POSS) cage is combined with 3,4‐ethylenedioxythiophene under the same roof. The corresponding monomer called EDOT‐POSS is used to get soluble poly(3,4‐ethylenedioxythiophene) (PEDOT‐POSS) analogue. Both chemically and electrochemically obtained polymers are soluble in common organic solvents like dichloromethane, chloroform, tetrahydrofuran, and so forth. The PEDOT‐POSS has somewhat higher band gap (1.71 eV at 618 nm) than its parent PEDOT (1.60 eV at 627 nm) and as expected the PEDOT‐POSS exhibits higher optical contrast (74% at 618 nm) and coloration efficiency (582 cm²/C for 100% switching), lower switching time (0.9 s), higher electrochemical stability (93% of its electroactivity retains after 5000 cycles under ambient conditions) when compared to the PEDOT. A number of advantages of the PEDOT‐POSS over the PEDOT can make it a promising material in the areas of electro‐optical applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3935–3941     

Improved Electrochromic Performance of Poly(3,4‐ethylenedioxythiophene) by Incorporating a Three‐Dimensionally Ordered Macroporous Structure

In this paper, three‐dimensionally ordered macroporous (3DOM) poly(3,4‐ethylenedioxythiophene) (PEDOT) films were electropolymerized from an ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([Bmim]PF₆). The electrochromic performances of the 3DOM PEDOT films were studied. The 3DOM films exhibited high transmittance modulation (41.2 % at λ=580 nm), high ionic fast switching speeds (0.7 and 0.7 s for coloration and bleaching, respectively), and enhanced cycling stability relative to that exhibited by the dense PEDOT film. The relationship between the declining behavior of the transmittance modulation and the nanostructure of the film was investigated. A three‐period decay process was proposed to understand the declining behavior. The 3D interconnected macroporous nanostructure is beneficial for fast ion and electron transportation, high ion accessibility, and maintenance of structure integrity, which result in enhanced cycling stability and fast switching speeds.     

石墨烯/聚3，4-乙烯二氧噻吩复合物的电化学制备及其在超级电容器中的应用

首次提出了一种在离子液体中在石墨烯表面用恒电流法聚合3,4-乙烯二氧噻吩(EDOT)单体制备石墨烯/聚3,4-乙烯二氧噻吩(石墨烯/PEDOT)复合物的方法。用原子力显微镜、扫描电镜等技术表征证明石墨烯/PEDOT复合物是由PEDOT纳米谷粒状颗粒分散在石墨烯片表面而组成的。将该复合物用作超级电容器电极材料时,在1.0 A.g-1的充放电比电流下得到的比电容值为181 F.g-1。同时,该材料还显现出较好的充放电可逆性和稳定性。     

Electrochromic enhancement of poly(3,4‐ethylenedioxythiophene) films functionalized with hydroxymethyl and ethylene oxide

2‐((2,3‐Dihydrothieno[3,4‐b]dioxin‐2‐yl)methoxy)methyl oxirane (EDOT‐MO) was successfully synthesized by the reaction of epichlorohydrin with hydroxymethylated‐3,4‐ethylenedioxylthiophene (EDOT‐MeOH), which was synthesized via a simple four‐step sequence. Poly(hydroxymethylated‐3,4‐ethylenedioxylthiophene) (PEDOT‐MeOH) and poly(2‐((2,3‐dihydrothieno[3,4‐b]dioxin‐2‐yl)methoxy)methyl oxirane) (PEDOT‐MO) were electrosynthesized through electropolymerization of EDOT‐MeOH and EDOT‐MO, respectively. Structural, electrochemical, optical, and thermal properties of as‐formed polymers were investigated by FTIR, cyclic voltammetry, UV–vis, and thermogravimetry. Spectroelectrochemistry studies demonstrated that PEDOT‐MeOH and PEDOT‐MO could be reversibly oxidized and reduced accompany with obvious color changes. Further kinetic studies demonstrated that the introduction of hydroxymethyl or ethylene oxide group significantly improved electrochromic properties of 3,4‐ethylenedioxythiophene (PEDOT) and resulted in high contrast ratios (57.3% at 585 nm) and coloration efficiencies (338.5 cm² C^?1), low switching voltages, and fast response time. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1989–1999     

基于3,4-乙烯二氧噻吩和吡咯-3-甲酸的共聚物薄膜的制备、表征及电致变色性能

以3,4-乙烯二氧噻吩(EDOT)和吡咯-3-甲酸(P3C)为共聚单体,EDOT和P3C分别按物质的量比1∶1,3∶1,5∶1,10∶1配比,通过电化学聚合制得了4种聚(3,4-乙烯二氧噻吩-吡咯-3-甲酸)薄膜,并依次命名为P(EDOT∶P3C)-1,P(EDOT∶P3C)-3,P(EDOT∶P3C)-5和P(EDOT∶P3C)-10.光谱电化学测试结果表明,4种共聚物薄膜都具有优良的电致变色性能,同时具有较好的电化学活性和较高的光学对比度.与聚3,4-乙烯二氧噻吩(PEDOT)相比,P(EDOT∶P3C)能展示更丰富的颜色变化,如P(EDOT∶P3C)-1薄膜随着电压的变化,可呈现从暗红色、浅褐色、灰蓝色到蓝色的变化.此外,基于EDOT和P3C以及钛氧簇[Ti_7(OEt)_(19)O_5(CoBr)],我们还设计合成了含钛共聚物薄膜P(EDOT∶P3C)-1-Ti,该薄膜不仅具有电致变色性能,而且还具有电催化氧化水的活性.     

Electrochemical Polymerization of 3,4‐Ethylenedioxythiophene from Aqueous Solution Containing Hydroxypropyl‐β‐cyclodextrin and the Electrocatalytic Behavior of Modified Electrode Towards Oxidation of Sulfur Oxoanions and Nitrite

Poly(3,4‐ethylenedioxythiophene) (PEDOT) film was prepared on glassy carbon electrode from 0.1 M LiClO₄ aqueous solution containing 3,4‐ethylenedioxythiophene (EDOT) monomer and hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD), by multiple scan cyclic voltammetry. The effect of oxidation potentials on electropolymerization of EDOT was examined by chronoamperometry and cyclic voltammetric techniques. The results of potentiostatic experiments show that optimum potential range to obtain compact stable film was 0.9 to 1.05 V (vs. Ag/AgCl). At higher positive potential, i.e. above 1.05 V, polymer growth was hindered by passivation effect. The PEDOT film exhibited a strong absorption at 550 nm in the UV‐vis region and also a multicolor electrochromism in different buffer solutions (sky blue‐purple red). Cyclic voltammetric features of PEDOT‐coated electrode in pure supporting electrolyte suggested that charge transfer of the film resembles that of surface‐confined redox species. Finally, the electrocatalytic behavior of PEDOT‐modified electrode was tested towards oxidation of sulfur oxoanions and nitrite using cyclic voltammetry.     

单体摩尔比对共聚物电化学及电致变色性质的影响

通过电化学聚合法制备了3, 6-(二噻吩基)-9-(二茂铁甲酸己酯基)-咔唑(BTC-H-Fc)与3, 4-乙烯二氧噻吩(EDOT)不同摩尔比下的共聚物,并运用电化学、傅里叶变换红外(FT-IR)光谱及光谱电化学对其结构与性能进行了表征。研究结果表明所得共聚物均能显示良好的电化学特性,光谱电化学测试结果表明,当摩尔浓度比为1时, P(BTC-H-Fc:EDOT)-1中性态下表现浅绿色,且随着施加电压增加转变为绿色和紫色; P(BTC-H-Fc:EDOT)-4则显示了最丰富的颜色,可在中性态的红褐色、棕黄色、绿色、蓝色和紫色五种颜色之间可逆变换;当摩尔比继续增加时, P(BTC-H-Fc:EDOT)-8可以显示红褐色、灰黑色、蓝绿色和天空蓝四种颜色。另外,三种摩尔比的聚合物薄膜还具有不错的光学对比度,转换响应时间及着色效率,该性能为其在电致变色器件的应用提供了潜力。     

Electrochemical behaviour of poly(3,4-ethylenedioxythiophene) in a room-temperature ionic liquid

The cyclic voltammetry responses and the redox switching dynamics of poly(3,4-ethylenedioxythiophene) (PEDOT) in a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide (EMImTf₂N), were investigated. The shape of the cyclic voltammograms showed two anodic and two cathodic peaks. These peak currents varied linearly with the scan rate indicating a thin-layer behaviour. No memory effects were observed during the cyclic voltammetry experiments in this ionic liquid. On the other hand, the redox switching dynamics of PEDOT were studied by means of potential step experiments. The analysis of chronocoulograms in term of RC-circuits indicated that the time dependence of the charge transferred during the potential step showed two time constants. These results were consistent with the postulated structure or morphology of the PEDOT film which contained two types of coexisting zones: a compact and an open structures.     

Synthesis,Photophysical Properties of Tribranched Chromophores Based on 1,3,5‐Triazine Core and Different Electro‐donating End‐groups

Three two‐photon absorption (TPA) tribranched chromophores were successfully prepared, in which 1,3,5‐triazine is been as electron deficient core, 1,4‐phenylenedivinylene as conjugated bridge, 3,4‐ethylenedioxythiophene (EDOT) ( T1 ), N‐methylpyrrole ( T2 ) or triphenylamine ( T3 ) as electron‐donating end‐groups. Their photophysical properties were studied by absorption, one‐ and two‐photon fluorescence and TPA cross‐section determination. The nonlinear transmission (NLT) measurement in femtoseconds (fs) regime at 800 nm indicates that TPA cross‐section (₂ values of T1 , T2 and T3 with extended Π‐conjugated bridge are much larger than the corresponding chromophore T4 with a short length bridge, and TPA cross‐section of T1 with end‐groups EDOT exhibits a remarkable enhancement compared with T2 and T3 having the same length Π‐system. The chromophores T1 , T2 and T3 show also remarkable up‐converted luminescence and optical limiting activity.     

Solid state electrochromic device applications of N-(2-(thiophen-3-yl)methylcarbonyloxyethyl) maleimide

Homopolymer and copolymer of N-(2-(thiophen-3-yl)methylcarbonyloxyethyl) maleimide (NMThi) with thiophene [P(NMThi-co-Th)] were synthesized electrochemically in acetonitrile/borontrifluoride ethylether solvent mixture (1:1, v/v). Spectroelectrochemical analysis of the resulting copolymer reflected electronic transitions at 488 and 718 nm revealing π to π¹ transition and polaron formation, respectively. Switching ability was evaluated by a kinetic study via measuring the transmittance (%T) at the maximum contrast. Dual-type polymer electrochromic devices (ECDs) based on homopolymer (P(NMThi) and copolymer P(NMThi-co-Th) were constructed with poly(3,4-ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry and switching ability of the devices were investigated by UV–vis spectroscopy and cyclic voltammetry.     

Stabilized gold nanoparticles by reduction using 3,4-ethylenedioxythiophene-polystyrenesulfonate in aqueous solutions: nanocomposite formation, stability, and application in catalysis

Herein, we report a one-pot synthesis of highly stable Au nanoparticles (AuNPs) using 3,4-ethylenedioxythiophene (EDOT) as a reductant and polystyrene sulfonate (PSS-) as a dopant for PEDOT and particle stabilizer. The synthesis demonstrated in this work entails the reduction of HAuCl4 using EDOT in the presence of PSS-. The formation of AuNPs with concomitant EDOT oxidation is followed by UV-vis spectroscopy at various time intervals. Absorption at 525 nm is due to the surface plasmon band of AuNPs (violet), and broad absorption above 700 nm is due to oxidized PEDOT that was further characterized to be in its highly oxidized (doped) state, using FT-Raman spectroscopy. Transmission electron microscopy shows a polydisperse nature of the particles, and the selected area electron diffraction pattern reveals the polycrystalline nature of AuNPs. With stabilizers such as sodium dodecylsulfate (SDS) (green) and polyvinylpyrrolidone (PVP) (blue), the absorbance around 525 nm was found to be negligibly small, while PSS- showed high absorbance at 525 nm (violet) and above 700 nm (oxidized PEDOT). PSS- also allows complete oxidation of EDOT and serves as an effective dopant for PEDOT. While AuNPs covered by PEDOT alone cannot be dispersed in aqueous solutions, PSS- renders Au-PEDOT water soluble. The hydrodynamic diameter of the nanocomposite estimated from the dynamic light scattering (DLS) measurements increases in the order Na-PSS < SDS < PVP. Interestingly, the color of the Au(nano)-PEDOT/PSS- aqueous dispersion changed reversibly between violet and blue and vice versa on addition of NaOH and HCl, respectively. This reversible color change appears to be a combination effect of acid/base on the properties of PEDOT, in turn changing the environment around the embedded AuNPs. The nanoparticle dispersion also exhibited very high stability in presence of 3.0 M NaCl. Remarkably, the nanocomposite Au(nano)-PEDOT/PSS- was found to function as an effective catalyst to activate the reduction of 4-nitrophenol to 4-aminophenol in the presence of excess NaBH4, and the calculated apparent rate constant value of 4.39 x 10-2 s-1 is found to be higher than those obtained using other nanocomposites with SDS and PVP and comparable to the values reported in the case of other encapsulants.     

Surface-enhanced Raman scattering of EDOT and PEDOT on silver and gold nanoparticles

Surface-enhanced Raman scattering (SERS) spectra of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and its monomer 3,4-ethylenedioxythiophene (EDOT) on Ag and Au nanoparticles presenting different morphologies and stabilizing agents have been obtained using the excitation radiation at 633 nm. The SERS spectra of the monomer and polymer are strongly dependent both on the metal and capping agent of the substrate. SERS spectra of EDOT on Au nanospheres indicates that adsorption occurs with the thiophene ring perpendicular to the metal surface. In contrast, polymerization takes place on the silver surface of Ag nanospheres. EDOT adsorption on Ag nanoprisms with polyvinylpyrrolidone (PVP) as capping agent occurs similarly to that observed on gold. Surface-enhanced resonance Raman scattering (SERRS) spectra of PEDOT on gold nanostars that present a thick layer of PVP show no chemical interaction of PEDOT with the metal surface; however, when PEDOT is adsorbed on citrate stabilized gold nanospheres, the SERRS spectra suggest that thiophene rings are perpendicular to the surface. Oxidation of PEDOT also is observed on Ag nanospheres. The investigation of the interface between PEDOT and metal surface is crucial for the development in polymer-based optoelectronic devices since this interface plays a crucial role in their stability and performance.     

Synthesis, characterization and electrochromic properties of copolymer of 3-{[4-(thien-3-yl-methoxy)phenoxy]methyl}thiophene with thiophene

(3-{[4-(Thien-3-yl-methoxy)phenoxy]methyl}thiophene) (TMPMT) was synthesized via the reaction of 3-bromomethylthiophene with hydroquinone and characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). Electrochemical copolymerization of TMPMT with thiophene in acetonitrile/boron trifluoride diethyl etherate (AN/BFEE) solvent mixture was achieved using tetrabutylammonium tetrafluoroborate (TBAFB) as the supporting electrolyte. Resulting copolymer was characterized via cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), four probe technique conductivity measurement and UV-Vis spectroscopy. Spectroelectrochemical analysis of the copolymer [P(TTMT-co-Th)] revealed that π-π^∗ electronic transition occurs at 427 nm with a band gap value of 2.20 eV. Copolymer gives brown color at the fully reduced state whereas; at fully oxidized state the film has a gray-blue color. Kinetic studies were carried out at the maximum contrast wavelength upon measuring the percent transmittance, T% (7.6%) and switching time (2.0 s) to examine the switching ability of the copolymer. Dual type electrochromic device (ECD) of P(TMPMT-co-Th) and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed. Spectroelectrochemistry, switching ability, open circuit memory and stability of the device were examined by UV-Vis spectroscopy and cyclic voltammetry. The device switches between brown and blue at switching voltages of 0.0 V and 2.8 V with a short switching time of 1.4 s.     

Electrochemical Polymerisation of N‐Arylated and N‐Alkylated EDOT‐Substituted Pyrrolo[3,4‐c]pyrrole‐1,4‐dione (DPP) Derivatives: Influence of Substitution Pattern on Optical and Electronic Properties

New pyrrolo[3,4‐c]pyrrole‐1,4‐dione (DPP) derivatives carrying 3,4‐ethylenedioxy‐thiophenylphenyl (EDOT‐phenyl) substituent groups in the 3‐ and 6‐position, or in the 2‐ and 5‐position of the DPP chromophore were synthesised and electrochemically polymerised. The properties of the polymers were investigated using cyclic voltammetry and UV/Vis absorption spectroscopy. It was found that the optical and electronic properties differ greatly between the two polymers. Materials with EDOT‐phenyl groups in the 3‐ and 6‐positions represent conjugated polymers with a low oxidation potential and reversible electrochromic properties, whereas the polymer with EDOT‐phenyl groups in the 2‐ and 5‐positions is non‐conjugated and possesses a high oxidation potential and irreversible redox behaviour.

     

Water‐Assisted Vapor Deposition of PEDOT Thin Film

The synthesis and characterization of poly(3,4‐ethylenedioxythiophene) (PEDOT) using water‐assisted vapor phase polymerization (VPP) and oxidative chemical vapor deposition (oCVD) are reported. For the VPP PEDOT, the oxidant, FeCl₃, is sublimated onto the substrate from a heated crucible in the reactor chamber and subsequently exposed to 3,4‐ethylenedioxythiophene (EDOT) monomer and water vapor in the same reactor. The oCVD PEDOT was produced by introducing the oxidant, EDOT monomer, and water vapor simultaneously to the reactor. The enhancement of doping and crystallinity is observed in the water‐assisted oCVD thin films. The high doping level observed at UV–vis–NIR spectra for the oCVD PEDOT, suggests that water acts as a solubilizing agent for oxidant and its byproducts. Although the VPP produced PEDOT thin films are fully amorphous, their conductivities are comparable with that of the oCVD produced ones.