Fault‐Tolerant Dielectric Elastomer Actuators using Single‐Walled Carbon Nanotube Electrodes

Dielectric oil coated single-walled carbon nanotube electrodes for stable, large-strain actuation with dielectric elastomers

We fabricated organic field effect transistors (OFETs) by directly growing poly (3-hexylthiophne) (P3HT) crystalline nanowires on solution processed aligned array single walled carbon nanotubes (SWNT) interdigitated electrodes by exploiting strong π-π interaction for both efficient charge injection and transport. We also compared the device properties of OFETs using SWNT electrodes with control OFETs of P3HT nanowires deposited on gold electrodes. Electron transport measurements on 28 devices showed that, compared to the OFETs with gold electrodes, the OFETs with SWNT electrodes have better mobility and better current on-off ratio with a maximum of 0.13 cm(2)/(V s) and 3.1 × 10(5), respectively. The improved device characteristics with SWNT electrodes were also demonstrated by the improved charge injection and the absence of short channel effect, which was dominant in gold electrode OFETs. The enhancement of the device performance can be attributed to the improved interfacial contact between SWNT electrodes and the crystalline P3HT nanowires as well as the improved morphology of P3HT due to one-dimensional crystalline nanowire structure.

This paper reports a novel supercapacitor electrode design based on poly(3,4-propylenedioxypyrrole) (PProDOP) electropolymerized onto thin films of single walled carbon nanotubes (SWNTs) on glass substrates. This permits the electropolymerization of thicker PProDOP films than can be deposited onto flat gold-coated Kapton electrodes and a correspondingly greater capacitance per unit area. A pyrene functionalized polyfluorene, designated Sticky-PF, was designed and used as an effective monolayer interfacial adhesion modifier between the SWNT films and PProDOP via noncovalent self-assembly onto the SWNT film surfaces before polymer electrodeposition. The thickness of the electrodeposited PProDOP was found to be self-limiting at thicknesses characteristic of each substrate electrode. Optimized areal capacitance values for PProDOP on flat gold and Sticky-PF coated SWNT films were measured to be 8.1 mF/cm2 and 16.4 mF/cm2, respectively, with the twofold enhancement due to the thicker films possible on the SWNT electrode. The specific capacitance of PProDOP on gold and Sticky-PF|SWNT film substrates were found to be similar at 141 F/g and 122 F/g, respectively, indicating the capacitance to be due to the electroactive polymer. The areal capacitance values of the corresponding supercapacitor devices constructed with Au/Kapton substrates was 3.2 mF/cm2, whereas a significantly greater value of 8.8 mF/cm2 was measured for the Sticky-PF|SWNT film substrates. The supercapacitors prepared using the Au/Kapton substrates were highly stable, retaining 80% of their electroactivity after 32 700 nonstop charge/discharge cycles (100% depth of discharge). Supercapacitors made using the Sticky-PF|SWNT substrates showed a steady loss of capacitance to about 57% of the original value (to 5.0 mF/cm2) after 32 700 charge/discharge cycles, which was still 38% larger than the initial capacitance of the gold electrode devices.

Sputtered transparent electrodes for optoelectronic devices: Induced damage and mitigation strategies

Spiro-OMeTAD versus PTAA for single-walled carbon nanotubes electrode in perovskite solar cells

Well dispersed silver nanoparticles (AgNPs) of different sizes on single walled carbon nanotubes (SWCNTs) were synthesized by a facile room-temperature deposition–precipitation process. The morphology and microstructure of samples examined by the transmission electron microscopy showed a monodispersed silver particle decorated SWCNT of as determined by the Rietveld phase analysis of powder X-ray diffraction patterns. The chemical state of silver determined from the binding energies of high resolution Ag 3d peaks from X-ray photoelectron spectroscopy revealed a silver oxidation state. Electrochemical properties were studied using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance studies. Silver decorated SWCNTs demonstrated to be effective bifunctional charge collectors and active electrode materials for a supercapacitor, exhibiting a higher specific capacitance compared to pristine SWCNT . An enhancement observed with AgNP decoration is highly size-dependent and is related to the improved intertube contact resistance, electroactive surface considerations, as well as the participation of Ag in a faradaic reaction induced pseudocapacitance. Decorating the SWCNT with AgNP doubled the energy density of the device, which on charge–discharge cycling retained 84% of the initial capacitance at the end of .

Biointerfaces capable of biological recognition and specificity are very important for the development of carbon nanotube based biosensors. Here, we explore experimentally the effects of O2 plasma treatment on the biomolecule immobilization properties of single-walled carbon nanotube (SWCNT) electrodes for electrochemical biosensing. The SWCNT film was integrated into an electrochemical three-electrode system on a glass substrate and then treated with an O2 plasma to improve its electrochemical response. Glucose oxidases, antibodies, and deoxyribonucleic acids (DNAs) were covalently immobilized on the plasma-functionalized (pf) SWCNT working electrodes, and the electrochemical and bioelectrocatalytic properties of three biomolecular assemblies generated on the pf-SWCNT electrodes were investigated using cyclic voltammetry, square-wave voltammetry, and chronoamperometry. The pf-SWCNT films were found to provide electrochemical biosensing electrodes having high electroactivity and sensitivity for detecting glucoses, antigens, and DNA molecules.

Dielectric Elastomers (DE) are currently being rapidly researched and developed all over the world as a technology that has begun to be incorporated at a practical level. As a product, game vibrators using DEs are already on the market in the United States and Europe. However, much of the market demand is dominated by more output-focused applications such as DE power suits, DE motors, DE muscles for robots, and larger DE power systems. Attempts have been made to improve elastomers and use new carbon foam materials such as single-walled carbon nano tubes (SWCNTs) and multi-walled carbon nano tubes (MWCNTs) as electrodes for DEs to meet these demands. This paper discusses these issues. Also, by reversing the movement of the DE, it is possible to generate electricity with high efficiency. By attaching the power generation system to the robot, which generates electricity from the movement of the robot, and charges the robot’s battery of the robot, it becomes possible to move the robot more efficiently. This is also discussed in this paper

A versatile chemical functionalization of single‐walled carbon nanotubes (SWNT) is developed to eliminate the conductivity of metallic SWNTs in pristine SWNT mixtures, without sorting. Thanks to the high selectivity of the diazoether reagent, metallic SWNTs can be functionalized while preserving the transport properties of semiconducting SWNTs, even in nonindividually dispersed SWNT solutions. In this way, liters of aqueous semiconducting ink for printing or spray can be prepared at the laboratory scale and used for the fabrication of thin‐film transistors (TFT) by spraying. Diazoether grafting also improved SWNT dispersion by preventing rebundling. Consequently, while less conductive than pristine SWNTs, diazoether‐treated SWNTs provided higher TFT transconductance thanks to a more homogeneous percolation in the film. SWNT TFTs made on wafer and plastic with pristine and diazoether‐treated SWNTs were compared. Sprayed films of diazoether treated, unsorted SWNTs provided TFTs with ION/IOFF around 500, about 2 orders of magnitude higher than pristine SWNT TFTs. Mobilities were similar, up to 1 cm2/V s. Interestingly, diazoether‐treated SWNT TFTs kept a high ION/IOFF in a wide range of SWNT density and channel length, where pristine SWNT films became metallic.

Carboxylated single-walled carbon nanotubes (SWCNT) chemically assembled on gold substrate was employed as netlike electrode to investigate the charge-transfer process and electrode process kinetics using uric acid as an example. The electrochemical behavior of uric acid in carboxylated SWCNT system was investigated using cyclic voltammetry, chronoamperometry, and single potential time-based techniques. The properties of raw SWCNT electrode were also studied for comparison purpose. Uric acid has better electrochemical behavior whereas ascorbic acid has no effective reaction on the carboxylated SWCNT electrode. Cyclic voltammograms indicate that the assembled carboxylated SWCNT increases more active sites on electrode surface and slows down the electron transfer between the gold electrode and uric acid in solution. The charge-transfer coefficient (alpha) for uric acid and the rate constant (k) for the catalytic reaction were calculated as 0.52 and 0.43 s(-1), respectively. The diffusion coefficient of 0.5 mM uric acid was 7.5 x 10(-6) cm2 x s(-1). The results indicate that electrode process in the carboxylated SWCNT electrode system is governed by the surface adsorption-controlled electrochemical process.

In this work, we have fabricated thin film transistors (TFTs) from a solution-based indium gallium zinc oxide (IGZO) and single-walled carbon nanotube (SWNT) blend by varying SWNT concentration. In order to improve electrical performances of IGZO TFT, SWNTs were used as carrier transport rods. We found out that the saturation field effect mobility (μsat) and on/off current ratio varied when the SWNT concentration changed. The concentration of SWNT in the solution is a critical parameter to control the electrical performances of IGZO TFT. The optimized performance of IGZO TFT with 0.04 wt.% SWNT concentration is as follows: μsat of about 0.11 cm2/Vs, an on/off current ratio of ∼ 105, threshold voltage (Vth) of − 2.5 V, and a subthreshold slope (S-factor) of 4.1 V/decade.

With a patterned transparent electrode and compressive-elastic gel material, a multi-input transparent touch screen, which detects touch location and touch force, has been realised. The input device of this touch screen is composed of a flexible upper single wall carbon nanotube electrode (SWCNT), a lower indium tin oxide electrode layer, and a silicone gel layer between two electrodes. When a touch force ranging from 0 N to 5 N was applied to the surface of the upper electrode film, the silicone gel was compressed to change the distance between the two electrodes, which resulted in a capacitance change ranging from 1.92 to 3.42pF. The SWCNT electrode on the polyethylene terephthalate showed sufficient flexibility and robustness for mechanical deformation.

A method for creating reliable and low-resistance contacts between carbon nanotubes and microelectrodes

Glucose biofuel cell (GBFC) is a power supply device which has attracted considerable attention because of its green environmental protection and high economic benefits. Fuels like glucose and oxygen are ubiquitous in physiological fluids, allowing the direct harvest of energy from human bodies. Compared with conventional batteries such as Li-Po, GBFC is a more promising alternative to power medical devices without the need to be replaced or refueled. However, the energy conversion efficiency of the existing GBFCs still needs to be further improved for practical applications. In this paper, the performance of the GBFC was studied based on single-walled carbon nanotubes (SWCNTs), which have relatively high conductivity and large specific surface area that could improve the activity of enzymes immobilized on the electrode surface and thus realize the direct electron transfer (DET). After optimization of the catalysts’ amount, the GBFC based on SWCNTs performed well with two Pt layers sprayed on one side of the proton exchange membrane (PEM) and 1.5 mL glucose oxidase (GOx) dropped on the other side, which attained the highest open-circuit potential (OCP) of 0.4 V. After being encapsulated with a flexible porous enclosure made by polydimethylsiloxane (PDMS), the biological compatibility of the completed GBFC has been successfully improved, which provides great potential for powering wearable or implantable devices.

In this work, we have proposed and achieved a hybrid thin film transistor (TFT) by embedding single-walled carbon nanotube (SWNT) array into an amorphous indium gallium zinc oxide (a-IGZO) channel. The SWNT array has been integrated into the TFT channel by Langmuir-Blodgett method. The proposed hybrid channel has improved the carrier mobility of the TFT by four times and on/off current ratio by 20 times compared to that of the pure a-IGZO channel TFTs. In the hybrid channel, SWNT array works as the high-speed carrier transport path. Both the density and alignment of the SWNTs in the array are critical for controlling TFT performance.