Article

Transparent, conductive carbon nanotube films

Department of Physics, University of Florida, Gainesville, FL 32611, USA.
Science (Impact Factor: 33.61). 09/2004; 305(5688):1273-6. DOI: 10.1126/science.1101243
Source: PubMed

ABSTRACT

We describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, electrically conducting films of pure single-walled carbon nanotubes and the transfer of those films to various substrates. For equivalent sheet resistance, the films exhibit optical transmittance comparable to that of commercial indium tin oxide in the visible spectrum, but far superior transmittance in the technologically relevant 2- to 5-micrometer infrared spectral band. These characteristics indicate
broad applicability of the films for electrical coupling in photonic devices. In an example application, the films are used to construct an electric field–activated optical modulator, which constitutes an optical analog to the nanotube-based field effect transistor.

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    • "Carbon nanotubes (CNTs) and graphene are particularly promising as potential ITO replacements in TCFs due to their unique properties. They have neutral color (in contrast to the yellowish color of ITO)[6], can be easily transferred to flexible substrates such as polyethylene terephthalate (PET)[10]and retain their excellent conductivity even after repeated bending[11]. However, CNT-and graphene-based TCFs have to demonstrate optoelectrical performance that matches or is superior to that of ITO-based TCFs. "
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    ABSTRACT: Carbon nanomaterials (carbon nanotubes (CNTs) and graphene) are promising materials for optoelectronic applications, including flexible transparent and conductive films (TCFs) due to their extraordinary electrical, optical and mechanical properties. However, the performance of CNT- or graphene-only TCFs still needs to be improved. One way to enhance the optoelectrical properties of TCFs is to hybridize CNTs and graphene. This approach leads to creation of a novel material that exhibits better properties than its individual constituents. In this work, the novel hybrid CNT-graphene nanomaterial was fabricated by graphene oxide deposition on top of CNT films. The graphene oxide was then reduced by thermal annealing at ambient atmosphere or in H2 atmosphere. At the final step the CNT-graphene hybrids were chemically doped using gold(III) chloride. As a result, we show that the hybrids demonstrate excellent optoelectrical performance with the sheet resistance as low as 73 Ω/□ at 90% transmittance.
    Full-text · Article · Jan 2016
    • "its complicated producing process, with methods such as high vacuum sputtering included, also increases the cost of its products. Considering the urgent requirement in the field of flexible electronics, many efforts have been made to develop new flexible transparent conductors to replace ITO, examples including conductive polymers,[4,5]carbon nanotubes (CNTs),[6,7]graphene,[2,8,9]metal grids,[10,11,12]random or aligned networks of metallic nanowires,131415and so on. Among these candidates, silver nanowires (AgNWs) films have shown a comparable optical and electrical performances with those of ITO and therefore are regarded as the one of the leading & emerging candidate materials for new generation TCE.16171819However, the performance of AgNWs electrode has been limited due to some factors like high wire to wire junction resistance,[13,16,20]the low corrosion resistance,[21,22]and the high surface roughness.[23]Another "

    No preview · Article · Dec 2015 · Nano Research
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    • "Microscopy images of CNT membranes show that the CNTs are distributed randomly in the membrane plane (Li et al., 2013; Wu et al., 2004), and the 2D simulation model is accordingly established, as shown in Fig. 3. In the representative area element of CNT network in Fig. 3(a), CNTs are simplified as line segments with the length l CNT , and the position and orientation of the CNTs are determined by the midpoint (X 1 , X 2 ) and the angle θ. "
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    ABSTRACT: For carbon nanotube (CNT) networks, with increasing network density, there may be sudden changes in the properties, such as the sudden change in electrical conductivity at the electrical percolation threshold. In this paper, the change in stiffness of the CNT networks is studied and especially the existence of stiffness threshold is revealed. Two critical network densities are found to divide the stiffness behavior into three stages: zero stiffness, bending dominated and stretching dominated stages. The first critical network density is a criterion to judge whether or not the network is capable of carrying load, defined as the stiffness threshold. The second critical network density is a criterion to measure whether or not most of the CNTs in network are utilized effectively to carry load, defined as bending–stretching transitional threshold. Based on the geometric probability analysis, a theoretical methodology is set up to predict the two thresholds and explain their underlying mechanisms. The stiffness threshold is revealed to be determined by the statical determinacy of CNTs in the network, and can be estimated quantitatively by the stabilization fraction of network, a newly proposed parameter in this paper. The other threshold, bending–stretching transitional threshold, which signs the conversion of dominant deformation mode, is verified to be well evaluated by the proposed defect fraction of network. According to the theoretical analysis as well as the numerical simulation , the average intersection number on each CNT is revealed as the only dominant factor for the electrical percolation and the stiffness thresholds, it is approximately 3.7 for electrical percolation threshold, and 5.2 for the stiffness threshold of 2D networks. For 3D networks, they are 1.4 and 4.4. And it also affects the bending–stretching transitional threshold, together with the CNT aspect ratio. The average intersection number divided by the fourth root of CNT aspect ratio is found to be an invariant at the bending–stretching transitional threshold, which is 6.7 and 6.3 for 2D and 3D networks, respectively. Based on this study, a simple piecewise expression is summarized to describe the relative stiffness of CNT networks, in which the relative stiffness of networks depends on the relative network density as well as the CNT aspect ratio. This formula provides a solid theoretical foundation for the design optimization and property prediction of CNT networks.
    Full-text · Article · Nov 2015 · Journal of the Mechanics and Physics of Solids
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