Morphology Of PEDOT Research Articles

The synthesis of poly(3,4-ethylenedioxythiophene) micro/nano-spheres by the demulsifying treatment

Poly(3,4-ethylenedioxythiophene) (PEDOT) microspheres were formed after the demulsifying treatment when acetone was used as the deemulsifier and dodecylbenzene sulfonic acid (DBSA) was used as the surfactant. We compared the properties of PEDOT with and without the demulsifying treatment as well as observed the morphological and structural changes along this treatment. PEDOT chains changed from rigid to coil conformation during the demulsifying treatment due to the strong interaction between polar acetone molecules and PEDOT chains, which induced PEDOT morphological transformation. Meanwhile, the close solubility parameters of acetone and PEDOT allowed the acetone molecules to penetrate into PEDOT agglomerates and fulfilled this morphological change. The investigation about the acetone volumes and the types of organic solvent to the morphology of PEDOT after the demulsifying treatment demonstrated the morphological transformation is an automatic process initiated by the appropriate organic solvent. PEDOT microspheres after the demulsifying treatment exhibited better capacitance behavior than that of PEDOT without this treatment when they were applied as the electrodes of supercapacitors.

Light induced electropolymerization of poly(3,4-ethylenedioxythiophene) on niobium oxide

The photoelectrochemical polymerization of poly(3,4-ethylenedioxythiophene), PEDOT, was successfully realized on anodic film grown to 50 V on magnetron sputtered niobium. Photocurrent Spectroscopy was employed to study the optical properties of Nb/Nb 2O 5/PEDOT/electrolyte interface in a large range of potential, and to get an estimate of the band gap and flat band potential of both the oxide and the polymer. Scanning Electron Microscopy was used to study the morphology of PEDOT. Both the optical and morphological features of the photoelectrochemically grown polymer were compared with those showed by PEDOT electropolymerized on gold conducting substrate.

Synthesis and characterization of poly(3,4‐ethylenedioxythiophene) nanoparticles obtained through ultrasonic irradiation

AbstractPoly(3,4‐ethylenedioxythiophene) (PEDOT) nanoparticles with a size of 50–100 nm were prepared by the oxidation polymerization of the monomer 3,4‐ethylenedioxythiophene (EDOT) under ultrasonic irradiation. The structure and morphology of PEDOT, as well as the electrical conductivity were characterized. Compared with the conventional stirring method, the PEDOT nanoparticles prepared by ultrasonic irradiation have a smaller particle size and are more uniform and spherical due to the dispersion, emulsifying and disruption effects of ultrasound. The yield of PEDOT by ultrasonic irradiation can reach ∼ 50%, and the conductivity of PEDOT is high up to 11 S/cm. A decrease in particle size due to the ultrasonication can lead to more effective doping and enhanced conductivity. The reaction time, temperature and ultrasound power output have significant effects on the field and electrical conductivity of PEDOT. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The Morphology of Poly(3,4-Ethylenedioxythiophene)

Poly(3,4-ethylene dioxythiophene) (PEDOT) is a chemically stable, conjugated polymer that is of considerable interest for a variety of applications including coatings for interfacing electronic biomedical devices with living tissue. Here, we describe recent work from our laboratory and elsewhere to investigate the morphology of PEDOT in the solid state. We discuss the importance of oxidative chemical and electrochemical polymerization, as well as the critical role of the counterion used during synthesis and film deposition. We have obtained information about the morphology of PEDOT from a number of different complimentary techniques including X-ray diffraction, optical microscopy, scanning electron microscopy, transmission high-resolution electron microscopy, and low-voltage electron microscopy. We also discuss results from ultraviolet-visible light spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). PEDOT is a relatively rigid polymer that packs in the solid state at a characteristic face-to-face distance (010) of ∼0.34 nm, similar to graphite. These sheets of oriented PEDOT molecules are separated from one another by ∼1.4 nm laterally, with the (100) distance between layers quite sensitive to the choice of counterion used during sample preparation. The order in the films is typically modest, although this also depends on the counterion used and the method of film deposition. The films can be organized into useful structures with a variety of nanoscale dissolvable templates (including fibers, particles, and lyotropic mesophases). When PEDOT is electrochemically deposited in the presence of bromine counterions, highly ordered crystalline phases are observed. It is also possible to deposit PEDOT around living cells, both in vitro and in vivo.

Inspection of substrate-heated modified PEDOT:PSS morphology for all spray deposited organic photovoltaics

Organic solar cells were fabricated by spray deposition of highly conductive PEDOT:PSS. Both PEDOT:PSS (Clevios PH750) and an active layer were spray deposited by the substrate heating method. In order to improve the conductivity of spray-deposited PEDOT:PSS, DMF or DMSO was added to it. As a result, surface morphology of PEDOT:PSS with DMSO-(/DMF) changed and its conductivity improved by about 10,000 times that of pure PEDOT:PSS. Solar cells fabricated using spray-deposited DMSO-added PEDOT:PSS as a transport layer showed a power conversion efficiency (PCE) of ∼3%, an open voltage of 0.62 V, and a short circuit current of 14.02 mA/cm 2.

Mechanical characterization of PEDOT:PSS thin films

By tensile testing the mechanical properties of thin films of the intrinsically conductive poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) under different relative humidities are investigated. It can be shown that the fracture behaviour strongly depends on humidity and reaches from brittle to plastic. The fracture surfaces are first investigated by scanning electron microscopy (SEM). The surfaces change from smooth at 23% rH to rough with shear lips for samples tested at 55% rH. Atomic force microscopy then reveals the topography of fracture surfaces at the nanometer scale and thus gives insights into the morphology of PEDOT:PSS thin films. By combining the experimental findings of the tensile tests and the AFM scans a micromechanical model for the deformation behavior of PEDOT:PSS can then be derived.

Influence of Ionic Liquids on the Electrical Conductivity and Morphology of PEDOT:PSS Films

Different ionic liquids (ILs) have been used as dopants in conducting polymer aqueous dispersion (PEDOT:PSS) leading to films of PEDOT:PSS/IL with enhanced electrical conductivity (up to 136 S cm-1). After the addition of the ILs, AFM images of the films show a three-dimensional conducting network of highly conducting PEDOT exhibiting preferred paths for charge carrier transport.

New Composite DMFC Anode with PEDOT as a Mixed Conductor and Catalyst Support

AbstractThe conducting polymer PEDOT is tested as a carbon substitute material for the DMFC anode. Electrochemical experiments are carried out in a three‐electrode half‐cell at room temperature. The first part of this paper focuses on the characterization of PEDOT and PEDOT‐PSS as a diffusion layer material. PEDOT/C cyclic voltammograms are recorded in 1 M H2SO4 in the range between the hydrogen evolution and polymer over‐oxidation potentials. The incorporation of the PSS counter‐ion into the polymer matrix leads to higher impedance values compared to PEDOT without PSS. The second part deals with the study of PEDOT as a Pt catalyst support. It is found that the partial over‐oxidation of PEDOT enhances the activity of Pt for methanol oxidation. This can be explained by a change in the morphology of PEDOT that probably improves methanol diffusion within the reaction layer. The degradation of the conducting polymer is confirmed by SEM, EDX, and FTIR measurements.

Mild oxygen plasma treated PEDOT:PSS as anode buffer layer for vacuum deposited organic light-emitting diodes

The surface morphology of PEDOT:PSS after mild oxygen plasma treatment were investigated by scanning electron microscopy and atomic force microscopy. The nanometer-scale islands on the surface of treated PEDOT:PSS were observed. Vacuum deposited organic light-emitting diodes (OLEDs) with treated PEDOT:PSS as anode buffer layer had been fabricated. The OLEDs with an appropriately treated PEDOT:PSS as anode buffer layer exhibited significantly enhanced lifetime and decreased driving voltage. The results suggest that the appropriate mild oxygen plasma treatment of PEDOT:PSS layers may be useful for the improvement of the interface with the hole transport layer and enhanced device performance.

Improved stability of OLEDs with mild oxygen plasma treated PEDOT:PSS

We demonstrate improved stability of OLEDs with mild oxygen plasma-treated poly (3,4-ethylenedioxythiophene) doped with poly (styrenesulfonate) (PEDOT:PSS) as anode buffer layer. The devices with treated PEDOT:PSS layer exhibited dramatically enhanced lifetime by a factor of 9 compared to the control devices. We investigated the substantial changes in surface morphology of PEDOT:PSS layer after the mild oxygen plasma treatment by scanning electron microscopy and atomic force microscopy. We found that the appropriate treatment can form uniformly distributed nano scaled hillocks/islands on the surface of PEDOT:PSS layer, which possibly result in improved contact to hole transport layer and thus enhanced lifetime of the devices.