Conductive polymer

About: Conductive polymer is a research topic. Over the lifetime, 21817 publications have been published within this topic receiving 692491 citations. The topic is also known as: intrinsically conducting polymer & ICP.

High stretchable MWNTs/polyurethane conductive nanocomposites

Abstract: Stretchable conductive polymers have aroused extensive interest in research recently due to their hi-tech applications in the fields of novel electronics, particularly for flexible electronic displays, smart textiles, medical electronics, sensors and actuators. In this study, we describe a novel elastic conductive nanocomposite made with multiwall carbon nanotubes (MWNTs) and polyurethane (PU). With the aid of an ionic liquid and under the condition of uniaxial tension, the MWNTs can form well-developed conducting networks in the PU matrix. The developed nanocomposite inherited advantageous properties from its constituents, namely the high conductivity from MWNTs, and the high elastomeric mechanical properties from the PU. Moreover, the stretchable conductive nanocomposite can be uniaxially stretched up to 100% without significant variation in electrical conductivity. The measurement of temperature dependent conductivity indicates that a 3D hopping mechanism dominates the conductivity of MWNTs.

Conducting poly(aniline) nanotubes and nanofibers: controlled synthesis and application in lithium/poly(aniline) rechargeable batteries.

Abstract: The primary aim of this work was to synthesize aligned perchloric-acid-doped poly(aniline) (HClO 4 -doped PANI) nanotubes by a simple alumina template method and to investigate their application in lithium/poly(aniline) rechargeable batteries. Powder X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) analysis were used to characterize the nanostructures obtained. The second aim addressed the preparation of HClO 4 -doped PANI microspheres and nanofibers on a large scale through a modified spraying technique, since the template synthesis has limitations in mass production. The present synthesis methods are simple and can be extended to the preparation of a broad range of one-dimensional conductive polymers. Furthermore, electrochemical measurements showed that the as-prepared HClO 4 -doped PANI nanotubes exhibit better electrode performances than their commercial counterparts because they possess more active sites, higher conductivity, and relative flexibility. This indicates that HClO 4 -doped poly(aniline) nanomaterials are promising in the application of lithium/polymer rechargeable batteries.

Optical outcoupling enhancement in organic light-emitting diodes: highly conductive polymer as a low-index layer on microstructured ITO electrodes.

Abstract: Organic light-emitting diodes (OLEDs) are now entering mainstream display markets and are also being explored for next-generation lighting applications. In both types of applications, high external quantum efficiency (EQE) is of premium importance for both low power consumption and long lifetime. It is well known that one of the bottlenecks in achieving high EQE in OLEDs is the low light-extraction efficiency, which is limited to <20%, mostly because total internal reflections occurring at interfaces between optically distinctive layers confine a significant portion of the light within the substrate (1⁄4 ‘‘substrate-confined’’ mode) or within the organic/indium tin oxide (ITO) layers (1⁄4 ‘‘wave-guided’’ mode). Hence, many device structures have been proposed to extract light that would not normally be outcoupled: some have attempted to extract the light that is confined in a substrate by introducing structures such as microlens array (MLA) or pyramidal arrays on the backside of the substrate, where other research groups have tried to extract the light that is confined within organic/ITO layers by introducing optical structures such as photonic crystals or low-index grids that can disrupt the wave-guiding of the light within the organic/ITO layers. The lattermay be carried out in a direct way by converting wave-guided modes directly into outcoupled modes or in an indirect way by converting wave-guided modes into substrate-confined modes and then extracting them with structures mentioned in the former approach. Criteria for choosing a specific method or structure over others depend on the target applications: for display applications, methodologies such as MLA and substrate structuring are often avoided due to their optical blurring effect; for lighting applications, such methods are readily accepted, but complex processes that add too much cost are generally not welcomed. In both cases, compatibility with a common fabrication technique and large-area fabrication is strongly preferred, and the Lambertian angular dependence and the absence of spectral dependence are also preferred in most situations. Here we introduce a novel anode structure based on micropatterned ITOs coated with high-conductivity (HC)-grade poly(3,4ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) layers. This proposed electrode structure can improve the outcoupling efficiency of OLEDs in a relatively simple way without severe spectral dependence, blurring (optional), or deviation from the normal angular dependence. Figure 1 illustrates a tilted top-view and cross-section of the proposed anode structure and its working principle. ITO layers are patterned so that the square opening (Wo Wo) repeats in a square lattice layout with a spatial period ofWt. For simplicity, we consider a situation where Wt1⁄4 2 Wo. In this case, the width of ITO strips (WITO (1⁄4Wt–Wo)) next to each opening equalsWo, and the ITO-less portion is 25% per each unit cell. The spatial period and the dimension of openings are chosen to be sufficiently larger than the emission wavelength so that a geometric optic approach can be valid and spectral dependence may be ignored. Each pattern may have a taper angle utaper, as defined in Figure 1a. A high-conductivity PEDOT:PSS (Baytron PH 500, HC Starck, Inc.) layer is coated throughout the anode area over the patterned anode. Organic layers and metal cathodes are then deposited to complete the device. Note that the light emitted with a small angle within the emission layer, which would normally be wave-guided throughout the organic/ ITO layers, is now guided either solely within organic layers (the ray in red coming from the left side in Figure 1b) or solely within ITO layers (the ray in blue coming from the right side in Figure 1b), because the refractive index ( 1.42 at l1⁄4 550 nm) of PEDOT:PSS is lower than those of ITOs and typical organic layers used in OLEDs. Upon hitting the structured region once or multiple times, the guided light will change its direction so that it can be directly coupled out. Some portion of the wave-guided mode can also be converted to a substrate-confined mode (see Figure S1 in Supporting Information). It has to be noted that patterned ITO electrodes alone without the PEDOT:PSS overcoat would not work effectively, because organic layers and ITO layers are optically almost identical due to their similar refractive indices. The low refractive index of a PEDOT:PSS layer is indeed the characteristic that enables internal reflections at the structured interfaces, which are among the key processes that must occur in order for the guided light to be converted to an outcoupled or a substrate-confined mode. In addition to the optical benefits noted above, it is also critical that, in the region without ITO, the HC-grade PEDOT:PSS layer provides an electrical sheet conduction and works as an anode independently so that there is no inactive area in the devices. In fact, we note each anode region consisting solely of PEDOT:PSS is surrounded by ITO electrodes, resembling the conductive grid structure suggested by Leo and his coworkers that can ensure

Polyethylenedioxythiophene coatings for humidity, temperature and strain sensing polyamide fibers

Abstract: Conductive polyamide fibers were prepared by impregnating their fabric in an aqueous dispersion of poly(3,4-ethylenedioxythiophene–poly(4-styrenesulfonate) (PEDOT–PSS). The morphology of the coating layers was studied by scanning electron microscope. The conductive fibers showed sensitivity to variations in surrounding humidity and temperature. This was monitored by the changeability of their specific resistance. The electrical response of PEDOT–PSS coated fabrics to external mechanical strain was also investigated. These single layer coatings of PEDOT on fabrics promise future applications such as in large surface area multifunctional sensors.