Transparent Single-walled Carbon Nanotube Research Articles

Self-passivation of transparent single-walled carbon nanotube films on plastic substrates by microwave-induced rapid nanowelding

We developed a straightforward method for enhancing the environmental stability of transparent single-walled carbon nanotube (SWCNT) network films on plastic substrates using a rapid microwave heating to produce SWCNT film–substrate nanowelding without any chemicals. The selective heating of SWCNTs induced by microwave irradiation leads to embedding the SWCNTs in the substrate, even within 10 s, without distortion of the substrate. The SWCNTs-embedded surface of the substrate played the role of a self-passivation layer that protected the SWCNTs from water molecules. The sheet resistance values of the nanowelded films had not increased more than 10%.

(Invited) Direct Synthesis and Potential Applications of Thin Highly Transparent Single Walled Carbon Nanotubes Films with High Conductivity

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Thermal and structural dependence of the band gap of quantum dots measured by a transparent film heater

We report the temperature dependence of the optical absorption and emission spectra of quantum dots (QDs) for three different nanocrystal (NC) structures (CdSe core, CdSe/CdS core/shell, and CdSe/CdS/ZnS core/multishell) in the solid film state. For this, a transparent single-walled carbon nanotube (SWCNT) film attached to a QD thin layer was tested as a heater. The temperature dependence of spectral shifts in both absorption and emission of QDs was measured in the range 300–450 K, and the Stokes shift was calculated by measuring the energy difference between the absorption and emission peaks. We found that the Stokes shift decreased as QD shells were added and the temperature was increased, indicating a weaker electron–phonon coupling in the QDs with additional shells at higher temperature. Finally, the band gap of the QDs was measured as a function of temperature. The Debye temperature was obtained by empirically fitting the energy band gap.

Graphene oxide as a multi-functional p-dopant of transparent single-walled carbon nanotube films for optoelectronic devices

Modulation of electronic structures and surface properties of transparent carbon nanotube films is a challenging issue for their application in optoelectronic devices. Here, we report, for the first time, that graphene oxide (GO) nanosheets play the role of a p-doping agent and surface energy modifier of single-walled carbon nanotube (SWCNT)-based transparent conducting electrodes (TCEs). The deposition of highly oxidized, small-sized (i.e., diameter of less than 500 nm) GO nanosheets onto a SWCNT network film reduces the sheet resistance of the pristine film to 60% of its original value by p-doping. The modified TCEs exhibit an outstanding optoelectronic feature of high conductivity with high transparency. Moreover, the wettability of the electrode surface was also noticeably increased, which is advantageous for the solution-based processing of organic electronics. Furthermore, the organic photovoltaic (OPV) cells with the GO-doped SWCNT anodes on flexible substrates were successfully demonstrated. In stark contrast to a power conversion efficiency of 0.44% for pristine SWCNT anodes, GO-doped SWCNT anodes show a drastically enhanced power conversion efficiency of 2.7%.

Solution Processing of Highly Conductive and Transparent Single-Walled Carbon Nanotube Films: Surfactant-Free Dispersions and Non-Acidic Dopants

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Highly conductive and transparent single-walled carbon nanotube thin films fabricated by gel coating

Transparent and conductive single-walled carbon nanotube (SWCNT) films were fabricated through gel coating. A gel was formed by directly dispersing a large amount of SWCNTs in a liquid nonionic surfactant like polyoxyethylene (12) tridecyl ether without a solvent by mechanical grinding and subsequent ultrasonication. SWCNT films were obtained by coating the gels on glass substrates and subsequently removing the surfactant through heating. The SWCNT films became very thin and transparent after heating at a temperature between 480 and 520 °C. They exhibited good uniformity and a high transmittance-to-sheet resistance ratio which is attributed to the long SWCNTs dispersed in the gels. Films with a sheet resistance of around 250 Ω □−1 at 80% transmittance were obtained. The films can be easily transferred from rigid substrates like glass to flexible polymer substrates like polyethylene terephthalate.

Low resolution Raman spectroelectrochemistry of single walled carbon nanotube electrodes

A new combination of a low-resolution Raman spectrometer with a minipotentiostat is presented in this work to perform in situ Raman measurements during electrochemical experiments with low-cost instrumentation. The instrumental setup has been used to study the electrochemical oxidation of transparent single walled carbon nanotube (SWCNT) films supported on non-conductive substrates. The spectroelectrochemical response provides the dependence of the characteristic signatures of the SWCNT bundles with the applied potential, which is similar to the response observed for SWCNT films deposited on conducting substrates. The evolution of both the electrical current and the Raman features differs considerably for pristine and oxidized films. The spectroscopic data reveal the occurrence of two kinds of irreversible breakdowns, “oxidative burning” and functionalization of the SWCNTs, in addition to reversible p-doping. 2D-correlation has been applied to analyze the evolution of the spectra with potential and has provided more detailed information than expected from a low spectral resolution spectrometer.

Fast and Efficient Purification for Highly Conductive Transparent Carbon Nanotube Films

A combination of thermal oxidation and thermal recovery was used to obtain transparent single-walled carbon nanotube (SWCNT) films with low sheet resistance. The process resulted in the effective removal of impurities and healing of defects in the SWCNTs, thus markedly increasing their conductivity. SWCNT samples before and after the process were analyzed by Raman spectroscopy, scanning and transmission electron microscopy, thermogravimetric analysis, contact angle measurement, and transparent conductive film fabrication. Following purification, the sheet resistance decreased from 5380 to 187 Ω/sq at 80% optical transmittance and at a wavelength of 550 nm. The process requires a short time of about 3 h and produces 30% yield of the as-produced sample.

Contact resistance of flexible, transparent carbon nanotube films with metals

We studied the contact properties of different metals to optically-transparent single-walled carbon nanotube (SWCNT) films using fabrication processes compatible with flexible electronic applications. The SWCNT films are deposited on flexible polyethylene terephthalate substrate and patterned in test structures optimized for contact resistance measurements for a particular metal contact. Specific contact resistance and current transfer length is determined for Pt, Cr, Cu, and Au contacts. We also evaluate effects of chemical doping and thickness of SWCNT films on the contact resistance. We find that the current transfer length, defining the minimal dimensions of efficient contacts to transparent SWCNT films, ranges from 8×10−6 to 10−4 m for different metals.

Flexible, transparent single-walled carbon nanotube transistors with grapheneelectrodes

This paper reports a mechanically flexible, transparent thin film transistor that usesgraphene as a conducting electrode and single-walled carbon nanotubes (SWNTs) as asemiconducting channel. These SWNTs and graphene films were printed on flexible plasticsubstrates using a printing method. The resulting devices exhibited a mobility of ∼ 2 cm2 V − 1 s − 1,On/Off ratio of ∼ 102, transmittanceof ∼ 81% and excellent mechanical bendability.

Improved conduction in transparent single walled carbon nanotube networks drop-cast from volatile amine dispersions

Thin single walled carbon nanotube (SWNT) films have been fabricated by drop-casting from SWNT dispersions in the volatile organic solvent, n-butylamine. This solvent can be removed by a simple annealing step which leads to substantial improvements in both transparency and conductivity of the films. The key factor in this increase in conductivity is reduction of barriers in SWNT networks upon surfactant removal, leading to enhanced conduction by variable range hopping. Contributions to the increased conductivity also arise from a thermally activated current at temperatures above ∼225 K and a small metallic contribution which is visible at temperatures below ∼3 K.

Electrocatalytic reduction of hydrogen peroxide by silver particles patterned on single-walled carbon nanotubes

Silver particles were patterned on flexible and transparent single-walled carbon nanotube (SWCNT) films using the electrochemical deposition method, and these patterned silver particles were then used as electrodes to detect hydrogen peroxide (H 2O 2). The sizes and densities of silver particles were tuned by varying the patterned design and the preparation conditions. Field emission-scanning electron microscopy revealed that the patterned silver particles were homogeneously distributed on the single-walled carbon nanotube films (AgPs-SWCNT), with an average size of 150–200 nm. X-ray diffraction patterns revealed four peaks, corresponding to a face-centered cubic silver crystal nanostructure. The AgPs-SWCNT sensor displayed a linear electrical response to H 2O 2 concentrations ranging from 0.016 mM to 18.085 mM. The detection limit and the sensitivity of the sensor were 2.76 μM and 10.92 μA mM −1 mm −2, respectively. Furthermore, the AgPs-SWCNT sensor was resistant to l-ascorbic acid as an interferent, indicating that it was selective for the electro-reduction of H 2O 2. In addition, the developed sensor showed a stable amperometric response to the reduction of H 2O 2 over an extended period of time.

Electrochemical sensing of hydroxylamine by gold nanoparticles on single-walled carbon nanotube films

Abstract The arrays of gold nanoparticles (AuNPs) were fabricated on flexible and transparent single-walled carbon nanotube (SWCNT) films using the electrochemical deposition method, and the patterned nanotubes were then used as electrodes for hydroxylamine detection. The sizes and densities of the AuNPs could easily be controlled by varying the amount of charge deposited, and the gold-deposited area showed a homogeneous distribution on the exposed SWCNT film surface. X-ray diffraction analysis of the AuNPs shows a face-centered cubic structure that is dominated by the lowest energy {111} facets. The oxidation of the hydroxylamine on the AuNP-deposited SWCNT films depended strongly on the solution pH, and the maximum catalytic current was observed at a pH of 9.0. A linear electrical response was observed for concentrations ranging from 0.016 to 0.210 mM, and the detection limit and the sensitivity were 0.72 μM and 165.90 μAmM −1 cm −2 , respectively. Moreover, the amperometric response in hydroxylamine showed a stable response for a long time (300 s), during which time it retained 94% of its initial value. In the long-term storage stability test, the current response to hydroxylamine decreased slightly, with only 17% leakage after 30 days.

Flexible and Transparent SWCNT Electrodes for Alternating Current Electroluminescence Devices

The application of transparent single-walled carbon nanotube (SWCNT) electrodes in rigid and flexible alternating current electroluminescence (ACEL) devices is demonstrated. SWCNT thin-film electrodes (50-160 nm) were made using a spray-coating process suitable for adjusting the transparency and sheet resistance. The dispersing procedure was optimized by comparing the transparency to sheet resistance ratio (T/R) of the electrodes. The emission intensity was as high as that for indium-tin oxide (ITO)-based ACEL devices with transparencies comparable to those of ITO-coated polymer slides.

The production of transparent carbon nanotube field emitters using inkjet printing

This study reports the field-emission characteristics of transparent single-walled carbon nanotube (SWCNT) film printed using an inkjet. Pure SWCNTs dispersed in dimethylformamide were printed in a transparent layer on indium–tin oxide-coated glass and annealed at 350 °C. The SWCNTs were aligned vertically through a surface treatment that involved detaching a sticky tape off. The front and back of the fabricated device produced simultaneous emissions of identical quality. In addition, inkjet printing directly achieved a patterned emission, without a secondary pattern process. This method provides a scheme to fabricate direct aligned SWCNT patterns without using additives.

Ultra Smooth, Large Area, High Uniformity, Conductive Transparent Single-Walled Carbon Nanotube Films for Photovoltaics Produced by Ultrasonic Spraying

not Available.

Micropatterning of Transparent Single-Walled Carbon Nanotube Films by Capacitively Coupled Plasma System

not Available.

Electrochemical patterning of gold nanoparticles on transparent single-walled carbon nanotube films

We report a simple, low cost, electrochemical deposition method to pattern gold nanoparticles on flexible, transparent, single-walled carbon nanotube (SWCNT) films, and demonstrate the application of the gold-patterned SWCNT films as surface-enhanced Raman spectroscopy substrates and biosensing electrodes for non-enzymatic glucose detection.

Flexible and Transparent SWCNT Electrodes for Alternating Current Electroluminescence (ACEL) Devices

AbstractThe application of transparent single-walled carbon nanotube (SWCNT) electrodes in rigid and flexible alternating current electroluminescence (ACEL) devices is demonstrated. SWCNT thin film electrodes (50 – 160 nm) were made using a spray-coating process suitable for adjusting transparency and sheet resistance. The emission intensity was as high as for indium tin oxide (ITO) based ACEL devices with transparencies comparable to ITO coated polymer slides.

A Simple Approach to the Fabrication of Transparent Single-Wall Carbon Nanotube Films of High Electrical and Optical Performance

A Simple Approach to the Fabrication of Transparent Single-Wall Carbon Nanotube Films of High Electrical and Optical Performance