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Showing papers on "Conductive polymer published in 2012"


Journal ArticleDOI
20 Apr 2012-Science
TL;DR: It is shown that surface modifiers based on polymers containing simple aliphatic amine groups substantially reduce the work function of conductors including metals, transparent conductive metal oxides, conducting polymers, and graphene.
Abstract: Organic and printed electronics technologies require conductors with a work function that is sufficiently low to facilitate the transport of electrons in and out of various optoelectronic devices. We show that surface modifiers based on polymers containing simple aliphatic amine groups substantially reduce the work function of conductors including metals, transparent conductive metal oxides, conducting polymers, and graphene. The reduction arises from physisorption of the neutral polymer, which turns the modified conductors into efficient electron-selective electrodes in organic optoelectronic devices. These polymer surface modifiers are processed in air from solution, providing an appealing alternative to chemically reactive low–work function metals. Their use can pave the way to simplified manufacturing of low-cost and large-area organic electronic technologies.

1,870 citations


Journal ArticleDOI
TL;DR: In this article, the authors summarized thirty years' research efforts in the field of organic compounds for rechargeable lithium batteries and compared the cell performances of these materials, providing a comprehensive overview of the area, and straightforwardly revealing the advantages/disadvantages of each class of materials.
Abstract: Organic compounds offer new possibilities for high energy/power density, cost-effective, environmentally friendly, and functional rechargeable lithium batteries. For a long time, they have not constituted an important class of electrode materials, partly because of the large success and rapid development of inorganic intercalation compounds. In recent years, however, exciting progress has been made, bringing organic electrodes to the attention of the energy storage community. Herein thirty years' research efforts in the field of organic compounds for rechargeable lithium batteries are summarized. The working principles, development history, and design strategies of these materials, including organosulfur compounds, organic free radical compounds, organic carbonyl compounds, conducting polymers, non-conjugated redox polymers, and layered organic compounds are presented. The cell performances of these materials are compared, providing a comprehensive overview of the area, and straightforwardly revealing the advantages/disadvantages of each class of materials.

1,096 citations


Journal ArticleDOI
TL;DR: The scalable synthesis and excellent electrode performance of the PAni hydrogel make it an attractive candidate for bioelectronics and future-generation energy storage electrodes.
Abstract: Conducting polymer hydrogels represent a unique class of materials that synergizes the advantageous features of hydrogels and organic conductors and have been used in many applications such as bioelectronics and energy storage devices. They are often synthesized by polymerizing conductive polymer monomer within a nonconducting hydrogel matrix, resulting in deterioration of their electrical properties. Here, we report a scalable and versatile synthesis of multifunctional polyaniline (PAni) hydrogel with excellent electronic conductivity and electrochemical properties. With high surface area and three-dimensional porous nanostructures, the PAni hydrogels demonstrated potential as high-performance supercapacitor electrodes with high specific capacitance (∼480 F·g-1), unprecedented rate capability, and cycling stability (∼83% capacitance retention after 10,000 cycles). The PAni hydrogels can also function as the active component of glucose oxidase sensors with fast response time (∼0.3 s) and superior sensitivity (∼16.7 μA·mM-1). The scalable synthesis and excellent electrode performance of the PAni hydrogel make it an attractive candidate for bioelectronics and future-generation energy storage electrodes.

986 citations


Journal ArticleDOI
TL;DR: These PEDOT:PSS films with conductivity and transparency comparable to ITO can replace ITO as the transparent electrode of optoelectronic devices.
Abstract: The conductivity of PEDOT:PSS films was significantly enhanced from 0.3 S cm(-1) to 3065 S cm(-1) through a treatment with dilute sulfuric acids. PEDOT:PSS films with a sheet resistance of 39 Ω sq(-1) and transparency of around 80% at 550 nm are obtained. These PEDOT:PSS films with conductivity and transparency comparable to ITO can replace ITO as the transparent electrode of optoelectronic devices.

949 citations


Journal ArticleDOI
TL;DR: In this article, conducting polymers poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANi), and polypyrrole (PPy) were directly coated on the surface of reduced graphene oxide (RGO) sheets via an in situ polymerization process to prepare conducting polymer-RGO nanocomposites with different loadings of the conducting polymer.
Abstract: In this work, conducting polymers poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANi), and polypyrrole (PPy) were directly coated on the surface of reduced graphene oxide (RGO) sheets via an in situ polymerization process to prepare conducting-polymer-RGO nanocomposites with different loadings of the conducting polymers. Experiment results showed that ethanol played an important role in achieving a uniform coating of the polymers on RGO sheets. The electrochemical capacitive properties of the composite materials were investigated by using cycle voltammetry and charge/discharge techniques. The composite consisting of RGO and PANi (RGO-PANi) exhibited a specific capacitance of 361 F/g at a current density of 0.3 A/g. The composites consisting of RGO and PPy (RGO-PPy) and PEDOT (RGO-PEDOT) displayed specific capacitances of 248 and 108 F/g, respectively, at the same current density. More than 80% of initial capacitance retained after 1000 charge/discharge cycles, suggesting a good cycling stability ...

624 citations


Journal ArticleDOI
TL;DR: In this paper, a review of the research progress on conducting polymers and their corresponding thermoelectric (TE) nanocomposites is presented, focusing on the polymeric and polymer-inorganic TE nanocomposition materials.

455 citations


Journal ArticleDOI
TL;DR: In this article, a review of the potential applications of these nanofibers and nanotubes in sensors, nanodiodes, field effect transistors, field emission and electrochromic displays, super-capacitors and energy storage, actuators, drug delivery, neural interfaces, and protein purification and its future prospects.
Abstract: Conducting polymers (CPs) have drawn considerable attention because of their economical importance, good environmental stability and electrical conductivity as well as due to their useful mechanical, optical and electronic properties. Some of the widest applications of conducting polymers include: they are used in electrostatic materials, conducting adhesives, electromagnetic shielding against electromagnetic interference (EMI), artificial nerves, aircraft structures, diodes, and transistors. This review covers some of the potential applications of these nanofibers and nanotubes in sensors, nanodiodes, field effect transistors, field emission and electrochromic displays, super-capacitors and energy storage, actuators, drug delivery, neural interfaces, and protein purification and its future prospects.

450 citations


BookDOI
01 Jul 2012
TL;DR: In this paper, the classification of Electrochemically Active Polymers (EAPs) is presented, along with methods of investigation and applications of EAPs in the chemical and electrochemical synthesis of conducting polymers.
Abstract: Introduction.- Classification of Electrochemically Active Polymers.- Methods of Investigation.- Chemical and Electrochemical Syntheses of Conducting Polymers.- Thermodynamic Considerations.- Redox Transformations and Transport Processes.- Applications of Conducting Polymers.- Historical Background (Or: There Is Nothing New Under the Sun).

448 citations


Journal ArticleDOI
TL;DR: A hybrid solar cell composed of Si nanocones and conductive polymer that can achieve a short-circuit current density up to 39.1 mA/cm(2), which is very close to the theoretical limit.
Abstract: Recently, hybrid Si/organic solar cells have been studied for low-cost Si photovoltaic devices because the Schottky junction between the Si and organic material can be formed by solution processes at a low temperature. In this study, we demonstrate a hybrid solar cell composed of Si nanocones and conductive polymer. The optimal nanocone structure with an aspect ratio (height/diameter of a nanocone) less than two allowed for conformal polymer surface coverage via spin-coating while also providing both excellent antireflection and light trapping properties. The uniform heterojunction over the nanocones with enhanced light absorption resulted in a power conversion efficiency above 11%. Based on our simulation study, the optimal nanocone structures for a 10 μm thick Si solar cell can achieve a short-circuit current density, up to 39.1 mA/cm2, which is very close to the theoretical limit. With very thin material and inexpensive processing, hybrid Si nanocone/polymer solar cells are promising as an economically...

422 citations


Journal ArticleDOI
22 May 2012-ACS Nano
TL;DR: To the best knowledge, this work is the first to use systemically administrated conductive polymer nanoparticles for highly effective in vivo PTT treatment in animals and encourages further explorations of those organic nanomaterials for cancer theranostic applications.
Abstract: In recent years, a wide range of near-infrared (NIR) light absorbing nanomaterials, mostly inorganic ones, have been developed for photothermal therapy (PTT) of cancer. In this work, we develop a novel organic PTT agent based on poly-(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS), a conductive polymer mixture with strong NIR absorbance, for in vivo photothermal treatment of cancer. After being layer-by-layer coated with charged polymers and then conjugated with branched polyethylene glycol (PEG), the obtained PEDOT:PSS-PEG nanoparticles are highly stable in the physiological environment and exhibit a stealth-like behavior after intravenous injection with a long blood circulation half-life. As a result, an extremely high in vivo tumor uptake of PEDOT:PSS-PEG attributed to the tumor-enhanced permeability and retention effect is observed. We further use PEDOT:PSS-PEG as a PTT agent for in vivo cancer treatment and realize excellent therapeutic efficacy in a mouse tumor model under NIR light irradiation at a low laser power density. Comprehensive blood tests and careful histological examination reveal no apparent toxicity of PEDOT:PSS-PEG to mice at our treated dose within 40 days. To our best knowledge, this work is the first to use systemically administrated conductive polymer nanoparticles for highly effective in vivo PTT treatment in animals and encourages further explorations of those organic nanomaterials for cancer theranostic applications.

393 citations


Journal ArticleDOI
TL;DR: In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), and UV-vis spectrography and electrical conductivity of PANI-ZnO composites were analyzed.

Journal ArticleDOI
TL;DR: The nanometer-size crystallization of poly(3,4-ethylenedioxythiophene) (PEDOT) inside the hydrophobic core region of PEDOT:PSS (PSS: poly(4-styrenesulfonate)) in a solid film is found by small and wide-angle X-ray scatterings using a synchrotron radiation source as mentioned in this paper.
Abstract: The nanometer-size crystallization of poly(3,4-ethylenedioxythiophene) (PEDOT) inside the hydrophobic core region of PEDOT:PSS (PSS: poly(4-styrenesulfonate)) in a solid film is found by small and wide-angle X-ray scatterings using a synchrotron radiation source. The clarified PEDOT:PSS structure indicates that a nanocrystal of PEDOT surrounded by PSS is grown in the solid film from randomly oriented PEDOT in a micelle dispersed in water during the course of film fabrication. The addition of ethylene glycol (EG) to the PEDOT:PSS water dispersion and post-treatment of the pristine film with EG both provide similar improvements in PEDOT crystallinity. The crystallite size of PEDOT increases up to a comparable size (∼4.8 nm) to the hydrophobic PEDOT core region of the micelle. The electrical conductivity of the solid film is concurrently enhanced by 2 orders of magnitude with the growing nanocrystal of PEDOT. These findings clearly demonstrate the importance of the single crystalline PEDOT assisted by EG to ...

Journal ArticleDOI
TL;DR: In this article, the authors summarized the synthetic strategies for various 1D conducting polymer nanostructures of conjugated polypyrrole (PPy), polyaniline (PANI), polythiophene (PTh), poly(p-phenylenevinylene) (PPV) and derivatives thereof.
Abstract: The past decade has witnessed increasing attention in the synthesis, properties, and applications of one-dimensional (1D) conducting polymer nanostructures. This overview first summarizes the synthetic strategies for various 1D nanostructures of conjugated polypyrrole (PPy), polyaniline (PANI), polythiophene (PTh), poly(p-phenylenevinylene) (PPV) and derivatives thereof. By using template-directed or template-free methods, nanoscale rods, wires/fibers, belts/ribbons, tubes, arrays, or composites have been successfully synthesized. With their unique structures and advantageous characteristics (e.g., high conductivity, high carrier mobility, good electrochemical activity, large specific surface area, short and direct path for charge/ion transportation, good mechanical properties), 1D conducting polymer nanostructures are demonstrated to be very useful for energy applications. Next, their applications in solar cells, fuel cells, rechargeable lithium batteries, and electrochemical supercapacitors are highlighted, with a strong emphasis on recent literature examples. Finally, this review ends with a summary and some perspectives on the challenges and opportunities in this emerging area of research.

Journal ArticleDOI
TL;DR: In this article, a skeleton/skin strategy for the preparation of free-standing, thin and flexible SWCNT/polyaniline (PANI) hybrid films by a simple in situ electrochemical polymerization method using directly grown carbon nanotubes with a continuous reticulate structure as template is presented.
Abstract: One of the most critical aspects in the preparation of single-walled carbon nanotubes (SWCNTs)/conducting polymer hybrid electrodes is to improve the energy density without seriously deteriorating their high power capability. Here, we report a “skeleton/skin” strategy for the preparation of free-standing, thin and flexible SWCNT/polyaniline (PANI) hybrid films by a simple in situ electrochemical polymerization method using directly grown SWCNT films with a continuous reticulate structure as template. In situ electrochemical polymerization can achieve effective deposition of PANI onto the surface of SWCNT bundles in the films and control the morphology and microstructure of the SWCNT/PANI hybrid films. In a SWCNT/PANI hybrid film, the directly grown SWCNT film with continuous reticulate architecture acts as the skeleton and PANI layers act as the skin. This unique continuous “skeleton/skin” structure ensures that these hybrid films have much higher conductivity compared to SWCNT/PANI composite films based on post-deposition SWCNT films. Flexible supercapacitors have been fabricated using the SWCNT/PANI hybrid films as both electrodes and charge collectors without metallic current collectors. High energy and power densities (131 W h kg−1 and 62.5 kW kg−1, respectively) have been achieved for the optimized assembly. The high electrical conductivity and flexibility, in combination with continuous porous architecture, suggests that the as-prepared ultrathin free-standing SWCNT/PANI hybrid films have significant potential as promising electrode materials for thin, lightweight and flexible energy storage devices with high performance.

Journal ArticleDOI
TL;DR: In this paper, a facile method for the construction of graphene oxide/polypyrrole (GO/PPy) nanocomposites via one-step coelectrodeposition was introduced.
Abstract: We introduce a facile method for the construction of graphene oxide/polypyrrole (GO/PPy) nanocomposites via one–step coelectrodeposition. In this process, the relatively large anionic GO serves as a weak electrolyte and is entrapped in the PPy nanocomposites during the electropolymerization of pyrrole, and also acts as an effective charge-balancing dopant within the PPy film. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) results demonstrate that the GO/PPy nanocomposites are successfully synthesized. The obtained GO/PPy nanocomposites exhibit good electrochemical properties and cycling performance, indicating a synergistic effect of PPy and GO. Taking its higher capacitance, lower cost and shorter processing time into consideration, GO may be a good choice for the fabrication of electrochemical supercapacitors based on conducting polymer nanocomposites. It should be noted that this coelectrodeposition is also applicable for the graphene oxide/poly[3,4-ethylenedioxythiophene] (GO/PEDOT) nanocomposites. Moreover, this facile and effective approach for the synthesis of GO/conducting polymer nanocomposites further extends the application of GO and should be very promising for the fabrication of inexpensive, high-performance electrochemical supercapacitors.

Journal ArticleDOI
TL;DR: In this work, the thermoelectric properties of the bulk of the conducting polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) were controlled electrically by varying the gate voltage.
Abstract: While organic field-effect transistors allow the investigation of interfacial charge transport at the semiconductor-dielectric interface, an electrochemical transistor truly modifies the oxidation level and conductivity throughout the bulk of an organic semiconductor. In this work, the thermoelectric properties of the bulk of the conducting polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) were controlled electrically by varying the gate voltage. In light of the growing interest in conducting polymers as thermoelectric generators, this method provides an easy tool to study the physics behind the thermoelectric properties and to optimize polymer thermoelectrics.

Journal ArticleDOI
TL;DR: It is shown that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers that increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude.
Abstract: There is a growing shift from liquid electrolytes toward solid polymer electrolytes, in energy storage devices, due to the many advantages of the latter such as enhanced safety, flexibility, and manufacturability. The main issue with polymer electrolytes is their lower ionic conductivity compared to that of liquid electrolytes. Nanoscale fillers such as silica and alumina nanoparticles are known to enhance the ionic conductivity of polymer electrolytes. Although carbon nanotubes have been used as fillers for polymers in various applications, they have not yet been used in polymer electrolytes as they are conductive and can pose the risk of electrical shorting. In this study, we show that nanotubes can be packaged within insulating clay layers to form effective 3D nanofillers. We show that such hybrid nanofillers increase the lithium ion conductivity of PEO electrolyte by almost 2 orders of magnitude. Furthermore, significant improvement in mechanical properties were observed where only 5 wt % addition of the filler led to 160% increase in the tensile strength of the polymer. This new approach of embedding conducting-insulating hybrid nanofillers could lead to the development of a new generation of polymer nanocomposite electrolytes with high ion conductivity and improved mechanical properties.

Journal ArticleDOI
29 Aug 2012-ACS Nano
TL;DR: It is demonstrated that the anisotropic growth of PANI at the nanometer scale can be kinetically controlled by employing a polymeric stabilizer, poly(N-vinylpyrrolidone), and it is believed that the stabilizer sterically restricts the directional fiber growth mechanism governing PANI chain growth in aqueous solution.
Abstract: Polyaniline (PANI) is one of the most widely investigated conducting polymers and is considered to be of practical use for many future applications. Here, we first demonstrate that the anisotropic growth of PANI at the nanometer scale can be kinetically controlled by employing a polymeric stabilizer, poly(N-vinylpyrrolidone). The polymerization rate became slower in the presence of the stabilizer (the rate constants calculated at the initial stage decreased with increasing concentration of the stabilizer), yielding PANI nanostructures with lower aspect ratios. Therefore, it is believed that the stabilizer sterically restricts the directional fiber growth mechanism governing PANI chain growth in aqueous solution. Three PANI nanostructures, specifically nanospheres, nanorods, and nanofibers, were fabricated and their oxidation/protonation levels were investigated systematically. It was found that the nanofibers had the most outstanding oxidation/protonation level accompanied by structural ordering (note that the only difference between the polymerization conditions in each case was the concentration of the stabilizer). We also examine the electrochemical properties of PANI nanostructure electrodes in three-electrode and two-electrode (actual capacitor cell) configurations. The intrinsic charge-transport ability of individual nanostructures strongly affected the electrochemical properties of the electrodes. Briefly, the nanofiber electrode had faster electrode kinetics and better capacitance than the nanorods and nanospheres. Lastly, an extrinsic factor, the interparticle contact resistance, also turned out to noticeably influence the capacitances of the electrodes.

Journal ArticleDOI
TL;DR: In this article, an all-solid-state flexible micro-supercapacitor was constructed by in situ electrodeposition of polyaniline (PANI) nanorods on the surface of reduced graphene oxide (rGO) patterns that are fabricated by micromolding in capillaries.
Abstract: A novel method is described for fabricating an all-solid-state flexible micro-supercapacitor. The microelectrodes of the supercapacitor are prepared by in situ electrodeposition of polyaniline (PANI) nanorods on the surface of reduced graphene oxide (rGO) patterns that are fabricated by micromolding in capillaries. The morphologies of PANI nanorods could be controlled by the concentration of aniline and the growth time in the electrodeposition process. The micro-supercapacitor possesses electrochemical capacitance as high as 970 F g−1 at a discharge current density of 2.5 A g−1, as well as good stability, retaining 90% of its initial capacitance after 1700 consecutive cycles for the synergistic effect of these new rGO/PANI nanostructures. The results show that the method could represent a route for translating the interesting fundamental properties of rGO and conducting polymers into technologically viable energy devices. Furthermore, this study might further guide the preparation of functional graphene-based materials.

Journal ArticleDOI
TL;DR: The study confirmed that polyaniline has not induced any sensitization and skin irritation either and cytotoxicity, which was higher for polyAniline hydrochloride compared to polyanILine base and was observed on both cell lines, was caused rather by the reaction by-products and residues than by polyanile itself.

Journal Article
TL;DR: In this paper, the mechanism for the synthesis of polyaniline and its electronic properties are presented in a short review, which is mainly due to the fact that the polymer and its derivatives or composites or co-polymers with other materials are easy to synthesise chemically or electrochemically by oxidative polymerisation.

Journal ArticleDOI
TL;DR: In this article, the PANI backbone chains were oriented along the CNT axis and therefore along the fiber axis due to the strong chemical interactions between PANI and CNTs.
Abstract: Carbon nanotube (CNT)/Polyaniline (PANI) thermoelectric composite nanofibers were prepared by a combination of in situ polymerization and electro-spinning processes. The obtained composite nanofibers were macroscopically aligned, while the CNTs were embedded in the nanofibers and oriented along the fiber axis. Polarized Raman spectra and X-ray diffraction (XRD) studies verified that the PANI backbone chains were orientated along the CNT axis and therefore along the fiber axis due to the strong chemical interactions between PANI and CNTs. The highly ordered arrangement of the PANI backbone chains not only reduces the π–π conjugated defects in the polymer backbone, but also increases the effective degree of electron delocalization and therefore enhances the carrier mobility in PANI, which results in the anisotropic thermoelectric properties especially with more than a doubled improvement of power factor in the orientation direction. This study not only provides an effective route to orient the conducting polymer chains at the molecular level but also demonstrates a possibility to design a conducting polymer with high thermoelectric performance through constructing a highly extended and orderly aligned backbone chain structure by chemical routes.

Journal ArticleDOI
TL;DR: In this paper, the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films are obtained using ionic liquids as additives.
Abstract: Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films are obtained using ionic liquids as additives. Upon adding 1-ethyl-3-methylimidazolium tetracyanoborate (EMIM TCB) to the conducting polymer, the conductivity increases to 2084 S cm−1; this is attributed to the phase separation of PSS leading to a structural change in the film. A comparative study with 1-butyl-3-methyl imidazolium tetrafluoroborate (BMIM BF4) shows that EMIM TCB gives higher conductivity and transmittance and can be regarded as one of the most promising additives for the preparation of indium tin oxide (ITO)-free organic devices using PEDOT:PSS/EMIM TCB as electrodes.

Journal ArticleDOI
Kaiwu Chen1, Libin Chen1, Yunqiang Chen1, Hua Bai1, Lei Li1 
TL;DR: In this paper, a general method for the fabrication of 3D porous graphene-based composite materials is reported, which involves two consecutive electrochemical steps, one for reducing a concentrated graphene oxide dispersion, and the second component is electrochemically deposited onto this 3D ERGO matrix, yielding a conductive graphene network.
Abstract: A general method for the fabrication of three-dimensional (3D) porous graphene-based composite materials is reported. This method involves two consecutive electrochemical steps. Firstly, 3D graphene (ERGO) porous material is prepared electrochemically by reducing a concentrated graphene oxide dispersion. Subsequently, the second component is electrochemically deposited onto this 3D ERGO matrix, yielding graphene-based 3D porous composite material. The prepared graphene-based composite materials have a conductive graphene network as the matrix, onto which the second component is homogeneously coated. Conducting polymers, noble metal nanoparticles and metal oxide were successfully incorporated into ERGO architectures, demonstrating the versatility of this method. Taking the ERGO–polyaniline composite as an example, the influence of deposition rate on the morphology of the composite was investigated. Finally, the application of the composite materials prepared with our method was discussed. The high surface area and low electrolyte transport resistance make these electrosynthesized composites suitable electrode materials for electrochemical devices. The ERGO–polyaniline composite electrode showed a high specific capacitance of 716 F g−1 at 0.47 A g−1, and this capacitance could be maintained at 502 F g−1 as the discharge current density was increased up to 4.2 A g−1.

Journal ArticleDOI
TL;DR: In this article, the interlayer adhesion of roll-to-roll processed flexible inverted P3HT:PCBM bulk heterojunction (BHJ) polymer solar cells is reported.

Journal ArticleDOI
TL;DR: In this paper, inverted polymer tandem solar cells where the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), modified at one interface with ethoxylated polyethylenimine (PEIE), acts as an efficient charge recombination layer.
Abstract: We report on inverted polymer tandem solar cells wherein the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), modified at one interface with ethoxylated polyethylenimine (PEIE), acts as an efficient charge recombination layer. This recombination layer shows very low optical absorption, high electrical conductivity, and a large work function contrast of 1.3 eV between its top and bottom interfaces. Its use yields tandem cells in which the open-circuit voltage is the sum of that of individual cells. The fill factor of tandem cells connected in series is found to be larger than that of single-junction cells. Its simple polymeric composition and its unprecedented performance make it a promising component for emerging organic photovoltaic technologies.

Journal ArticleDOI
TL;DR: Results showed that laser roughening of the underlying substrate did not affect the charge injection limit of the coated material, but significantly improved the passive stability and chronic stimulation lifetime without failure of the coating.

Journal ArticleDOI
TL;DR: In this paper, the electrical transport properties of poly(3,4-ethylenedioxythiophen)/poly(4-styrene-sulfonate) (PEDOT:PSS) with PEDOT-to-PSS ratios from 1:1 to 1:30 were investigated.
Abstract: We have investigated the electrical transport properties of poly(3,4-ethylenedioxythiophen)/poly(4-styrene-sulfonate) (PEDOT:PSS) with PEDOT-to-PSS ratios from 1:1 to 1:30. By combining impedance spectroscopy with thermoelectric measurements, we are able to independently determine the variation of electrical conductivity and charge carrier density with PSS content. We find the charge carrier density to be independent of the PSS content. Using a generalized effective media theory, we show that the electrical conductivity in PEDOT:PSS can be understood as percolation between sites of highly conducting PEDOT:PSS complexes with a conductivity of 2.3 (Ωcm)−1 in a matrix of excess PSS with a low conductivity of 10−3 (Ω cm)−1. In addition to the transport properties, the thermoelectric power factors and Seebeck coefficients have been determined. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

Journal ArticleDOI
TL;DR: In this paper, a detailed investigation into the thermoelectric properties of P3HT films is reported by employing a ferric salt of triflimide (TFSI−) anions as a dopant.
Abstract: Due to their low thermal conductivity, non-toxicity and low cost, conductive polymer materials are potential candidates for thermoelectric applications. Here, a detailed investigation into the thermoelectric properties of P3HT films is reported. A thermoelectric power factor over 20 μW m−1 K−2 at room temperature was obtained by employing a ferric salt of triflimide (TFSI−) anions as a dopant. Flexible films of P3HT-TFSI were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM), along with temperature-variant electrical measurements. Given the promising results obtained from ordinary P3HT films by a simple doping treatment, this work suggests the significance of the appropriate choice of dopants and/or counterions, as well as the polymers themselves.

Journal ArticleDOI
TL;DR: A hybrid system for producing conducting polymers within a doping hydrogel mesh that has superior mechanical stability and a modulus significantly closer to neural tissue than materials which are commonly used for medical electrodes is presented.
Abstract: A hybrid system for producing conducting polymers within a doping hydrogel mesh is presented. These conductive hydrogels demonstrate comparable electroactivity to conventional conducting polymers without requiring the need for mobile doping ions which are typically used in literature. These hybrids have superior mechanical stability and a modulus significantly closer to neural tissue than materials which are commonly used for medical electrodes. Additionally they are shown to support the attachment and differentiation of neural like cells, with improved interaction when compared to homogeneous hydrogels. The system provides flexibility such that biologic incorporation can be tailored for application.