Chemical synthesis of PEDOT nanofibers

A one-step, room-temperature method is described to chemically synthesize bulk quantities of microns long, 100-180 nm diameter nanofibers of electrically conducting poly(3,4-ethylenedioxythiophene)(PEDOT) in the form of powders, or as optically transparent, substrate-supported films using a V2O5 seeding approach.     

Preparation of poly(3,4-ethylenedioxythiophene)(PEDOT) coated silica core-shell particles and PEDOT hollow particles

Nanometre-sized PEDOT-silica core-shell particles were synthesized and self-assembled into crystalline colloidal arrays with a reflection peak in the visible region; these particles were also etched with hydrofluoric acid to produce hollow PEDOT particles.     

Solvent effects on the electrochemical p-doping of PEDOT

EQCM experiments were carried out on PEDOT films exposed to TEABF(4)/CH(3)CN and TEABF(4)/CH(2)Cl(2) under permselective conditions and subjected to cyclic voltammetry in the potential range corresponding to p-doping. Current and frequency responses were used to obtain time-resolved ion and solvent flux data as functions of potential. Normalization of these fluxes with potential scan rate distinguishes thermodynamically (ir)reversible elementary steps in the overall redox process. The specific mechanisms are different in the two solvents, although both show mechanistic switches at partial redox conversion during both p-doping and undoping. These different mechanistic signatures are characterized according to the solvent identity, by different patterns of deviation from scan rate normalization for the experimentally measured ion and solvent fluxes. Comparison of these ion and solvent fluxes demonstrates that the rates of solvent expulsion (during doping) and entry (during undoping) are key determinants of mechanism. In both switching directions there are changes between kinetically limiting and rapid solvent transfer that depend upon solvent identity, i.e. the mechanism depends substantially upon charge state, switching direction and solvent. These mechanistic pathways and shifts can be visualized by a scheme-of-cubes representation.     

Capacitance characteristic of PEDOT electrodeposited on different substrates

Journal of Solid State Electrochemistry - Poly(3,4-ethylenedioxythiophene) (PEDOT) has been electrochemically deposited on carbon paper (CP), stainless steel mesh (SSM), stainless steel (SS), and...     

Deposition of Au and Ag nanoparticles on PEDOT

The deposition of Au and Ag, locally and from bulk solution, on poly(3,4-ethylenedioxythiophene) (PEDOT) was studied. Specifically, PEDOT was electrochemically polymerized onto a glassy carbon (GC) electrode and used for bulk deposition of Au and Ag from their respective ions dissolved in the solution as well as for the local deposition of these metals using scanning electrochemical microscopy (SECM). These two sets of experiments were utilized to investigate the difference between Au and Ag electrochemical deposition on PEDOT. In particular, SECM experiments, which were conducted by the controlled anodic dissolution of Au and Ag microelectrodes close to GC/PEDOT, probed the effect of different PEDOT oxidation states on local deposition. The current-time transients recorded during the deposition, combined with scanning electron microscopy and EDX analysis provided insight into the reduction processes. AuCl(4)(-) and Ag(+) ions were electrochemically reduced at a potential equal to and more negative than the ions redox potentials (0.4 and 0.2 V, respectively) and more positive than -0.7 V, where the PEDOT starts transforming into the reduced, i.e. insulating, state. We found that the electroreduction of Ag(+) ions was diffusion-controlled and the PEDOT film served as a simple conductor. On the other hand, the reduction of AuCl(4)(-) ions was enhanced on GC/PEDOT as compared with bare GC, indicating that PEDOT catalyzes the reduction of AuCl(4)(-) to Au.     

导电聚(3,4-二氧乙基噻吩)/无机纳米复合材料研究

本论文围绕制备导电聚合物PEDOT(聚3,4-二氧乙基噻吩)与无机氧化物及金属纳米复合材料的研究,探索了不同复合材料所表现的独特的电学、光学和结构等方面性质,并建立了一种无模板制备有机/无机一维纳微米结构复合材料的一步合成新方法,制备了具有core-shell结构的PEDOT/PSS-ZnO,PEDOT/PSS-Au复合纳米线,取得了以下创新性结果.     

Kinetics and mechanism of the electrochemical p-doping of PEDOT

EQCM experiments were made on PEDOT films exposed to LiClO₄/CH₃CN under permselective conditions and subjected to cyclic voltammetry in the potential range corresponding to p-doping. Current and frequency responses were used to generate time-resolved ion and solvent flux data as functions of potential. These fluxes normalize with respect to scan rate during p-doping and undoping, but the responses in the two directions are not mirror images. The results lead to the following mechanistic conclusions. Coupled electron/anion transfer is the first, and non-rate limiting, step in both redox switching directions, but involves differently solvated and configured polymer in the two directions. Solvent transfer and polymer reconfiguration follow the charge transfer steps, but are kinetically inseparable on the timescales accessed. This mechanism can be visualized by a scheme-of-squares representation whose two coordinates are “coupled electron/anion transfer” and “coupled solvent transfer/polymer reconfiguration”. The data analysis protocol provides a powerful approach to identifying mechanistic pathways, particularly in situations corresponding to partial film redox conversion.     

Thermoelectric properties of PEDOT films prepared by electrochemical polymerization

Thermoelectric (TE) properties of flexible and free‐standing poly(3,4‐ethylenedioxythiophene) (PEDOT) films synthesized via galvanostatic polymerization of 3,4‐ethylenedioxythiophene in propylene carbonate containing sulfated poly(β‐hydroxyethers) (S‐PHE) as polymer electrolyte were elaborately studied. Both electrical conductivities (σ ) and Seebeck coefficients (S ) of the PEDOT:S‐PHE films were increased by decreasing the temperature (T ) or by increasing the current density (J ) during electrosynthesis. Possible reasons for the lack of a trade‐off relation commonly observed between σ and S are discussed on the basis of SEM and oxidation‐level measurements. Preparation of the PEDOT:S‐PHE films was optimized with respect to T and J . In addition, the oxidation level of the PEDOT:S‐PHE films was controlled by potential and the change of their TE performances was discussed in conjunction with the change of chemical species involved. The power factor (PF = σS ²) of the PEDOT:S‐PHE films reached 7.9 μW m^?1 K^?2, leading to a dimensionless TE figure‐of‐merit (ZT ) of 0.013. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 524–531     

修饰LB膜法制备聚3,4-乙烯二氧噻吩薄膜

采用修饰Langmuir-Blodget(LB)膜法以二十烷酸(AA) LB膜为模板, 通过3,4-乙烯二氧噻吩(EDOT)单体在LB膜亲水基团间聚合, 制备了AA/PEDOT复合LB膜. 实验分析表明薄膜具有较好的层状有序结构, 并进一步研究发现EDOT在AA多层膜中的聚合破坏了原有LB膜的有序性, 这与聚合过程对层状结构产生的破坏作用有关; 研究了薄膜导电性能, 发现AA/PEDOT多层膜的电导率随处理时间的变化产生突变, 这与多层膜中导电通道的“渝渗”有关, 在有效导电网络连通后电导率发生了突变. 测试结果还表明AA/PEDOT膜导电性明显优于PEDOT旋涂膜和十八胺-硬脂酸/聚(3,4)乙烯二氧噻吩-聚苯乙烯磺(ODA-SA/PEDOT-PSS)复合膜.     

PEDOT基光子晶体的制备及其电致变色性能研究

采用改进的Stöber法合成了单分散SiO₂微球, 通过垂直沉积组装成蛋白石结构光子晶体. 再使用电化学法在组装的SiO₂微球表面生成聚(3,4-乙撑二氧噻吩)(PEDOT), 得到核-壳结构的SiO₂@PEDOT光子晶体复合膜. 测试了SiO₂@PEDOT光子晶体薄膜的反射光谱、循环伏安曲线、多电位紫外反射光谱、对比度及响应时间等光学、电化学及电致变色性能. 结果表明, 该光子晶体薄膜在变色时颜色亮丽, 其色差值(26.82)比纯PEDOT薄膜(18.07)提高很多, 并且最大对比度可达39.8%, 高于纯PEDOT薄膜的27.4%, 同时响应时间变快. 此实验结果说明将光子晶体结构引入导电聚合物中, 能够提高其电致变色性能.     

Enhanced electrical properties of PEDOT:PSS via synergistic effect

As a representing conducting polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been widely employed in organic electronics. However, the electrical conductivity for pristine PEDOT:PSS is only between 0.1 and 0.5 S/cm. In order to enhance the conductivity, the silver nanowires (Ag NWs) were synthesized to dope PEDOT:PSS. It was found the electrical conductivity of PEDOT:PSS was improved to about 200 S/cm with Ag NWs. When double-wall carbon nanotube (DWCNT) was employed together with Ag NWs, the electrical conductivity was further improved to over 2800 S/cm. We proposed the synergistic working model between Ag NWs and CNTs for such enhancement. In this work, UV-vis-NIR spectra and SEM images were also employed to investigate the mechanism of electrical conductivity enhancement.     

聚乙撑二氧噻吩的导电性及现场ESR响应的研究

聚乙撑二氧噻吩(PEDOT)因为具有很高的稳定性和导电性，近年来受到了广泛 的注意并开始在许多方面得到实际应用．电化学聚合方法具有操作简便、易于控制 等优点．本文采用恒电位电化学聚合方法，在水溶液中Pt电极上制备了聚乙撑二氧 噻吩．研究了单体浓度、支持电解质种类、聚合电位等因素对聚合得到的PEDOT膜 导电性的影响．首次运用电化学现场ESR技术研究了水溶液中PEDOT膜的ESR响应， 结合电化学现场的膜电阻测量研究了PEDOT膜的导电性随所加电位的变化规律．结 果表明，PEDOT膜随不同电位的导电性的变化规律符合极化子—双极化子理论．     

Electrosynthesis and characterization of aminomethyl functionalized PEDOT with electrochromic property

We herein report the electrosynthesis of an aminomethyl functionalized poly(3,4-ethylenedioxythiophene)(PEDOT) derivative, poly(2'-aminomethyl-3,4-ethylenedioxythiophene)(PEDOT-Me NH2), in CH2Cl2-Bu4NPF6(0.1 mol·L-1) system containing 2% boron trifluoride diethyl etherate(BFEE). The electrochemical behavior, structure characterization, thermal properties and surface morphology of this novel polymer were systematically investigated by cyclic voltammetry(CV), Fourier-transform infrared spectroscopy(FTIR), thermogravimetry(TG) and scanning electron microscopy(SEM), respectively. Electrochemistry results demonstrated that PEDOT-Me NH2 film displayed good redox properties and high electrochemical stability. Besides, PEDOT-Me NH2 films exhibited the electrochromic nature with obvious color changing from purple in the reduced form to blue upon oxidation. By further investigation, kinetic studies revealed that PEDOT-Me NH2 film had decent contrast ratio(41.8%), favorable coloration efficiency(152.1 cm2·C-1), low switching voltages and moderate response time(2.4 s). Satisfactory results implied that the obtained PEDOT-Me NH2 film is a promising optoelectronic material and holds promise for electrochromic devices and display applications.     

Tuning of PEDOT:PSS Properties Through Covalent Surface Modification

Conductive polymer (poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) is an attractive platform for the design of flexible electronic, optoelectronic, and (bio)sensor devices. Practical application of PEDOT:PSS often requires an incorporation of specific molecules or moieties for tailoring of its physical–chemical properties. In this article, a method for covalent modification of PEDOT:PSS using arenediazonium tosylates was proposed. The procedure includes two steps: chemisorption of diazo‐cations on the PEDOT:PSS surface followed by thermal decomposition of the diazonium salt and the covalent bond formation. Structural and surface properties of the samples were evaluated by XPS, SEM‐EDX, AFM, goniometry, and a range of electric and optical measurements. The developed modification procedure enables tuning of the PEDOT:PSS surface properties such as conductivity and optical absorption. The possibility to introduce various organic functional groups (from hydrophilic to hydrophobic) and to create new groups for further functionalization makes the developed procedure multipurpose. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 378–387     

Flow Injection Analysis of Iodate Reduction on PEDOT Modified Electrode

Poly‐(3,4‐ethylenedioxythiophene) (PEDOT) films were electrodeposited by cyclic voltammetry on glassy carbon electrode at different anodic potentials in the range of 1.0–1.5 V (Ag/AgCl) and its electrocatalytic properties towards reduction of iodate were reported. The effect of the pH of the solution on the response of PEDOT electrode towards iodate also studied. The modified electrode was employed successfully as an amperometric sensor for iodate in a flow injection apparatus. The repeatability of the method for 14 injections of a μM iodate solution was 7%. Interference from other oxidant anions such as nitrate was not noticeable, whereas bromate, chlorate and nitrite interfere at slight levels.     

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.

     

PEDOT films: multifunctional membranes for electrochemical ion sensing

Properties of electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT) films were studied from the point of view of direct use as ion-sensing membranes in potentiometric or amperometric sensors. Stable and reproducible potentiometric characteristics were obtained for PEDOT doped by poly(4-styrenesulfonate) ions, PEDOT(PSS) (cationic characteristics), and PEDOT doped by hexacyanoferrate(II) anions, PEDOT(HCF) (anionic characteristics). As shown by voltammetric and EDAX results, the anion exchange properties of the latter polymer result from gradual replacement of HCF ions by Cl^– anions from solution. The zero-current potentiometric detection limit of PEDOT(PSS), equal to 3×10^–6 M, can be shifted to 7×10^–7 M by polarization using a cathodic current density of 3×10^–7 A cm^–2. PEDOT films doped by Cl^– or PSS^– ions can be used as membranes for sensing anions or cations, respectively, under pulse amperometric conditions, within the range from 10^–4 to 1 M, comparable with that accessible by zero-current potentiometry. Dissolved oxygen (redox interferent of low charge transfer rate) exerts a minor influence on the slope of the potentiometric and amperometric characteristics of PEDOT films. Although the presence of redox reactants characterized by a high rate of charge transfer [Fe(CN)₆ ^3–/4–] results in the disappearance of the potential dependence on KCl concentration, this disadvantageous effect is much less significant under pulse amperometric conditions.Contribution to the 3rd Baltic Conference on Electrochemistry, GDASK-SOBIESZEWO, 23–26 April 2003. Dedicated to the memory of Harry B. Mark, Jr. (February 28, 1934–March 3rd, 2003)     

PEDOT: Fundamentals and Its Nanocomposites for Energy Storage

PEDOT, or poly(3,4-ethylenedioxythiophene), is among the most successful conducting polymer products because of its stable conductivity, colloidal processability, and rich assembly behavior. Since the very first patents on PEDOT filed in 1988, the material has been widely explored for decades in many applications. In this review, a comprehensive summary on the synthesis, processing and post-treatment of PEDOT will be presented for the sake of the discussion on PEDOT and its nanocomposites for energy storage. Knowing what PEDOT lends itself to the electrode materials is of importance to the rational design of energy storage devices that maximize the real-world performance. Based on these discussions, a roadmap for the development of PEDOT as promising multifunctional electrode component is presented.     

Tuning the gas sensing performance of single PEDOT nanowire devices

This paper reports the synthesis and dopant dependent electrical and sensing properties of single poly(ethylenedioxythiophene) (PEDOT) nanowire sensors. Dopant type (i.e. polystyrenesulfonate (PSS(-)) and perchlorate (ClO(4)(-))) and solvent (i.e. acetonitrile and 1 : 1 water-acetonitrile mixture) were adjusted to change the conjugation length and hydrophilicity of nanowires which resulted in change of the electrical properties and sensing performance. Temperature dependent coefficient of resistance (TCR) indicated that the electrical properties are greatly dependent on dopants and electrolyte where greater disorder was found in PSS(-) doped PEDOT nanowires compared to ClO(4)(-) doped nanowires. Upon exposure to different analytes including water vapor and volatile organic compounds, these nanowire devices displayed substantially different sensing characteristics. ClO(4)(-) doped PEDOT nanowires from an acetonitrile bath show superior sensing responses toward less electronegative analytes and followed a power law dependence on the analyte concentration at high partial pressures. These tunable sensing properties were attributed to variation in the conjugation lengths, dopant type and concentration of the wires which may be attributed to two distinct sensing mechanisms: swelling within the bulk of the nanowire and work function modulation of Schottky barrier junction between nanowire and electrodes.