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. 相似文献
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. 相似文献
The electrochemistry of poly(3,4-ethylenedioxythiophene) (PEDOT) was studied in two ionic liquids with bulky organic anions, i.e., 1-butyl-3-methylimidazolium (BMIM) diethylene glycol monomethyl ether sulfate (MDEGSO4) and BMIM octyl sulfate (OctSO4). BMIM-MDEGSO4 is a liquid, while BMIM-OctSO4 is in solid form at room temperature. Electrosynthesis of PEDOT in BMIM-MDEGSO4 with an EDOT concentration of 0.1 M and in BMIM-MDEGSO4/EDOT 1/1 (w/w) solution resulted in no polymer at all or a very limited amount of polymer on the electrode surface, as determined by cyclic voltammetry in 0.1 M KCl(aq) solution. In contrast, electrosynthesis of PEDOT in BMIM-OctSO4/EDOT 1/1 (w/w) resulted in a high yield of electroactive material on the electrode surface. Furthermore, electrosynthesis of PEDOT in ionic liquid–water solution (Cionic liquid=1.5 M) containing 0.1 M EDOT was also found to give a relatively high yield of electroactive material on the electrode surface, both for 1.5 M BMIM-MDEGSO4(aq) and 1.5 M BMIM-OctSO4(aq). The PEDOT electrodes showed an anionic potentiometric response in 10–5–10–1 M KCl(aq) solution, indicating a predominant anion transfer at the polymer–solution interface despite the relatively bulky anions (MDEGSO4– or OctSO4–) incorporated as counterions in PEDOT during electropolymerization. On the basis of electrochemical impedance spectroscopy, the charge (ion) transport properties of the polymer film were strongly influenced by the water content of the ionic liquid (Cionic liquid=0.05–2.0 M).Dedicated to Zbigniew Galus on the occasion of his 70th birthday 相似文献
We report that poly(3,4‐ethylenedioxythiophene) derived from poly(ionic liquid) (PEDOT:PIL) constitutes a unique polymeric hole‐injecting material capable of improving device lifetime in organic light‐emitting diodes (OLEDs). Imidazolium‐based poly(ionic liquid)s were engineered to impart non‐acidic and non‐aqueous properties to PEDOT without compromising any other properties of PEDOT. A fluorescent OLED was fabricated using PEDOT:PIL as a hole‐injection layer and subjected to a performance evaluation test. In comparison with a control device using a conventional PEDOT‐based material, the device with PEDOT:PIL was found to achieve a significant improvement in terms of device lifetime. This improvement was attributed to a lower indium content in the PEDOT:PIL layer, which can be also interpreted as the effective protection characteristics of PEDOT:PIL for indium extraction from the electrodes.
Carbon nanotubes (CNTs), either single wall carbon nanotubes (SWNTs) or multiwall carbon nanotubes (MWNTs), can improve the thermoelectric properties of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT?:?PSS), but it requires addition of 30-40 wt% CNTs. We report that the figure of merit (ZT) value of PEDOT?:?PSS thin film for thermoelectric property is increased about 10 times by incorporating 2 wt% of graphene. PEDOT?:?PSS thin films containing 1, 2, 3 wt% graphene are prepared by solution spin coating method. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy analyses identified the strong π-π interactions which facilitated the dispersion between graphene and PEDOT?:?PSS. The uniformly distributed graphene increased the interfacial area by 2-10 times as compared with CNT based on the same weight. The power factor and ZT value of PEDOT?:?PSS thin film containing 2 wt% graphene was 11.09 μW mK(-2) and 2.1 × 10(-2), respectively. This enhancement arises from the facilitated carrier transfer between PEDOT?:?PSS and graphene as well as the high electron mobility of graphene (200,000 cm(2) V(-1) s(-1)). Furthermore the porous structure of the thin film decreases the thermal conductivity resulting in a high ZT value, which is higher by 20% than that for a PEDOT?:?PSS thin film containing 35 wt% SWNTs. 相似文献
Recently, stretchable electrochemical sensors have stood out as a powerful tool for the detection of soft cells and tissues, since they could perfectly comply with the deformation of living organisms and synchronously monitor mechanically evoked biomolecule release. However, existing strategies for the fabrication of stretchable electrochemical sensors still face with huge challenges due to scarce electrode materials, demanding processing techniques and great complexity in further functionalization. Herein, we report a novel and facile strategy for one-step preparation of stretchable electrochemical biosensors by doping ionic liquid and catalyst into a conductive polymer (poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS). Bis(trifluoromethane) sulfonimide lithium salt as a small-molecule plasticizer can significantly improve the stretchability and conductivity of the PEDOT:PSS film, and cobalt phthalocyanine as an electrocatalyst endows the film with excellent electrochemical sensing performance. Moreover, the functionalized PEDOT:PSS retained good cell biocompatibility with two extra dopants. These satisfactory properties allowed the real-time monitoring of stretch-induced transient hydrogen peroxide release from cells. This work presents a versatile strategy to fabricate conductive polymer-based stretchable electrodes with easy processing and excellent performance, which benefits the in-depth exploration of sophisticated life activities by electrochemical sensing.A facile strategy for constructing stretchable sensors with excellent mechanical, electrochemical and biocompatible performance is developed, and in situ inducing and monitoring of stretch-evoked H2O2 release from cells has been successfully achieved. 相似文献
Poly(3,4ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been intensively studied for its thermoelectric applications. Structural modulation to improve crystalline ordering, chain conformation and film morphology is a promising way to decouple the trade-off between conductivity and Seebeck coefficient and thus improve the thermoelectric power factor. Post treatment with ionic liquid ([CoCl2 ⋅ 6H2O]:[ChCl]) bearing cobalt-containing anions resulted in a remarkable enhancement of the power factor to 76.8 μW m−1 K−2. This IL combines the influence of a high-boiling polar organic solvent and diffusing ions. A high σ mainly resulted from the efficient removal of PSS chains, ordering of the structure and delocalization of bipoloran-dominant transport after conformational change. The increase in S was not due to dedoping of PEDOT chains, but rather the sharp feature of the density of states at the Fermi level induced by ion-exchange with unconventional anions. 相似文献
Helical carbon and graphite films from helical poly(3,4‐ethylenedioxythiophene) (H‐PEDOT) films synthesized through electrochemical polymerization in a chiral nematic liquid‐crystal (N*‐LC) field are prepared. The microscope investigations showed that the H‐PEDOT film synthesized in the N*‐LC has large domains of one‐handed spiral morphology consisting of fibril bundles. The H‐PEDOT films exhibited distinct Cotton effects in circular dichroism spectra. The highly twisted N*‐LC with a helical pitch of smaller than 1 μm produced the H‐PEDOT film with a highly ordered morphology. The spiral morphologies with left‐ and right‐handed screws were observed for the carbon films prepared from the H‐PEDOT films at 800 °C and were well correlated with the textures and helical pitches of the N*‐LCs. The spiral morphologies of the precursors were also retained even in the graphite films prepared from the helical carbon films at 2600 °C. 相似文献
In this paper, we report a novel electrochemical doping method for conducting polymer films based on bipolar electrochemistry. The electrochemical doping of conducting polymers such as poly(3-methylthiophene) (PMT), poly(3,4-ethylenedioxythiophene) (PEDOT), and poly(aniline) (PANI) on a bipolar electrode having a potential gradient on its surface successfully created gradually doped materials. In the case of PEDOT film, the color change at the anodic side was also observed to be gradually transparent. PANI film treated by the bipolar doping gave a multicolored gradation across the film. The results of UV-vis and energy dispersive X-ray analyses for the doped films supported the distribution of dopants in the polymer films reflecting the potential gradient on the bipolar electrode. Furthermore, the reversibility of the bipolar doping of the PMT film was demonstrated by a spectroelectrochemical investigation. 相似文献
Poly(3,4-ethylenedioxythiophene) (PEDOT) was electropolymerised on aluminium substrates. The Al/Al oxide/PEDOT junction was
studied by electrochemical impedance spectroscopy, comparing the impedance response of the polymer film in oxidised, neutral
and reduced form. The p- and n-doping behaviour of the PEDOT films was studied by in situ external reflection Fourier transform
infrared spectroscopy during stepwise potential cycling of the films. The Al surface underneath the polymer was analysed with
X-ray photoelectron spectroscopy. The impedance spectra indicate that an insulating layer between the metal and the polymer
grows thicker during doping of the polymer film. The other techniques used suggest that this interfacial layer consists mainly
of Al oxides and fluorides. Neither the conductivity nor the dopability of the polymer is notably affected by the growing
of this insulating interfacial layer, which makes the concept of PEDOT electropolymerised on Al promising from an organic
electronics applications point of view. 相似文献
In this work, the suitability of imidazolium-based ionic liquid solvents is investigated for the dissolution and regeneration of silkworm (Bombyx mori) silk. Within an ionic liquid the anion plays a larger role in dictating the ultimate solubility of the silk. The dissolution of the silk in the ionic liquid is confirmed using wide-angle X-ray scattering. The dissolved silk is also processed into 100 mum-thick, two-dimensional films, and the structure of these films is examined. The rinse solvent, acetonitrile or methanol, has a profound impact on both the topography of the films and the secondary structure of the silk protein. The image depicts a silkworm cocoon dissolved in 1-butyl-3-methylimidazolium chloride and then regenerated as a film with birefringence. 相似文献
A PtAuPd ternary alloy nanoparticle film with high particle density and small particle size is fabricated on a novel mercapto ionic liquid film via ultrasonic-electrodeposition, which is characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and cyclic voltammetry. Owing to the excellent poison-tolerance and large effective surface area of the PtAuPd ternary alloy nanoparticles, the resulted composite film coated electrode presents high electrocatalytic activity and stability toward formaldehyde electro-oxidation. 相似文献