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Carbon nanotube (CNT) based optically transparent and electrically conductive thin films are fabricated on plastic substrates in this study. Single-walled carbon nanotubes (SWNTs) are chemically treated with a mixture of concentrated sulfuric acid and nitric acid before being dispersed in aqueous surfactant-contained solutions. SWNT thin films are prepared from the stable SWNT solutions using wet coating techniques. The 100 nm thick SWNT thin film exhibits a surface resistivity of 6 kohms/square nanometer with an average transmittance of 88% on the visible light range, which is three times better than the films prepared from the high purity as-received SWNTs. 相似文献
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Svensson J Lindahl N Yun H Seo M Midtvedt D Tarakanov Y Lindvall N Nerushev O Kinaret J Lee S Campbell EE 《Nano letters》2011,11(9):3569-3575
Novel field effect transistors with suspended graphene gates are demonstrated. By incorporating mechanical motion of the gate electrode, it is possible to improve the switching characteristics compared to a static gate, as shown by a combination of experimental measurements and numerical simulations. The mechanical motion of the graphene gate is confirmed by using atomic force microscopy to directly measure the electrostatic deflection. The device geometry investigated here can also provide a sensitive measurement technique for detecting high-frequency motion of suspended membranes as required, e.g., for mass sensing. 相似文献
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We demonstrate the biocompatibility of carbon nanotube fibers (CNFs) fabricated from single-wall carbon nanotubes. Produced by a particle-coagulation spinning process, CNFs are "hair-like" conductive microwires, which uniquely combine properties of porous nanostructured scaffolds, high-area electrodes, and permeable microfluidic conduits. We report that CNFs are nontoxic and support the attachment, spreading, and growth of mammalian cells and the extension of processes from neurons in vitro. Our findings suggest that CNF may be employed for an electrical interfacing of nerve cells and external devices. 相似文献
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Developments in the manufacturing technology of low-cost, high-quality carbon nanotubes (CNTs) are leading to increased industrial applications for this remarkable material. One of the most promising applications, CNT based transparent conductive films (TCFs), are an alternative technology in future electronics to replace traditional TCFs, which use indium tin oxide. Despite significant price competition among various TCFs, CNT-based TCFs have good potential for use in emerging flexible, stretchable and wearable optoelectronics. In this review, we summarize the recent progress in the fabrication, properties, stability and applications of CNT-based TCFs. The challenges of current CNT-based TCFs for industrial use, in comparison with other TCFs, are considered. We also discuss the potential of CNT-based TCFs, and give some possible strategies to reduce the production cost and improve their conductivity and transparency. 相似文献
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Little BK Li Y Cammarata V Broughton R Mills G 《ACS applied materials & interfaces》2011,3(6):1965-1973
Electrochemical gold plating processes were examined for the metallization of Kevlar yarn. Conventional Sn(2+)/Pd(2+) surface activation coupled with electroless Ni deposition rendered the fibers conductive enough to serve as cathodes for electrochemical plating. The resulting coatings were quantified gravimetrically and characterized via adhesion tests together with XRD, SEM, TEM; the coatings effect on fiber strength was also probed. XRD data showed that metallic Pd formed during surface activation whereas amorphous phases and trace amounts of pure Ni metal were plated via the electroless process. Electrodeposition in a thiosulfate bath was the most efficient Au coating process as compared with the analogous electroless procedure, and with electroplating using a commercial cyanide method. Strongly adhering coatings resulted upon metallization with three consecutive electrodepositions, which produced conductive fibers able to sustain power outputs in the range of 1 W. On the other hand, metallization affected the tensile strength of the fiber and defects present in the metal deposits make questionable the effectiveness of the coatings as protective barriers. 相似文献
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Carbon nanotube/graphene nanocomposite as efficient counter electrodes in dye-sensitized solar cells
We demonstrated the replacement of the Pt catalyst normally used in the counter electrode of a dye-sensitized solar cell (DSSC) by a nanocomposite of dry spun carbon multi-walled nanotube (MWNT) sheets with graphene flakes (Gr-F). The effectiveness of this counter electrode on the reduction of the triiodide in the iodide/triiodide redox (I(-)/I(3)(-)) redox reaction was studied in parallel with the use of the dry spun carbon MWNT sheets alone and graphene flakes used independent of each other. This nanocomposite deposited onto fluorinated tin-oxide-coated glass showed improved catalytic behavior and power conversion efficiency (7.55%) beyond the use of the MWNTs alone (6.62%) or graphene alone (4.65%) for the triiodide reduction reaction in DSSC. We also compare the use of the carbon MWNT/Gr-F composite counter electrode with a DSSC using the standard Pt counter electrode (8.8%). The details of increased performance of graphene/MWNT composite electrodes as studied are discussed in terms of increased catalytic activity permitted by sharp atomic edges that arise from the structure of graphene flakes or the defect sites in the carbon MWNT and increased electrical conductivity between the carbon MWNT bundles by the graphene flakes. 相似文献
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《Composites Science and Technology》2004,64(13-14):2165-2175
Inter-laminar toughening from sparsely distributed chopped fibers is analyzed in this paper. A detailed micromechanical model describing the special toughening effects of those chopped Kevlar fibers lying within the delamination plane has been developed. To determine bridging forces of the Kevlar fibers lying in the matrix near a delamination-crack face, a simplified model based on coupling of matrix spalling (matrix fracture following by separation of fiber away from the matrix) and fiber pull-out is proposed. The model is then used to study toughening of carbon-fiber/epoxy composite laminates with chopped Kevlar fibers. The model shows that the energy dissipation in the pull-out process of chopped Kevlar fibers is much more than that in the matrix spalling process. The numerical results indicate that interfacial properties, interactions among Kevlar fibers and percentage of Kevlar fibers involved in crack bridging play important roles in delamination toughening. The modelling results are in good agreement with the experimental results available in the literature. 相似文献
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利用纤维素纳米晶须(CNCs)搭载碳纳米管(CNTs)在水相中形成均一稳定的纳米CNCs-CNTs导电复合物,并将其均匀分散于聚乙烯醇(PVA)基体中制得纺丝液,采用静电纺丝技术制备纤维定向排列的CNCs-CNTs/PVA复合导电膜。结果表明:CNCs-CNTs增强了纤维膜热力学性能,并赋予其导电功能;纤维的定向排列显著提高了膜的力学性能;随CNTs含量增加,纺丝液电导率和黏度提高,纤维直径减小;当CNCs和CNTs与PVA的质量比分别为8.0%和1.0%时,CNCs-CNTs/PVA的纤维直径、拉伸强度和电导率分别可达182 nm±35 nm、15.99 MPa±1.25 MPa和0.12 S/m±0.01 S/m;当电流密度为0.2 A/g时,其比电容可达127.1 F/g,且经过1 500次充放电循环后电容量仍保持在83.14%。基于导电膜优良的力学性能、热稳定性和导电性,CNCs-CNTs/PVA导电膜有望应用于可折叠超级电容器、柔性传感器和柔性电极材料等领域。 相似文献
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Carbon nanotube filters 总被引:4,自引:0,他引:4
Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus ( approximately 25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially. 相似文献
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Carbon nanotube electronics 总被引:1,自引:0,他引:1
Appenzeller J. Knoch J. Martel R. Derycke V. Wind S.J. Avouris P. 《Nanotechnology, IEEE Transactions on》2002,1(4):184-189
Presents experimental results on single-wall carbon nanotube field-effect transistors (CNFETs) operating at gate and drain voltages below 1V. Taking into account the extremely small diameter of the semiconducting tubes used as active components, electrical characteristics are comparable with state-of-the-art metal oxide semiconductor field-effect transistors (MOSFETs). While output as well as subthreshold characteristics resemble those of conventional MOSFETs, we find that CNFET operation is actually controlled by Schottky barriers (SBs) in the source and drain region instead of by the nanotube itself. Due to the small size of the contact region between the electrode and the nanotube, these barriers can be extremely thin, enabling good performance of SB-CNFETs. 相似文献
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Here we report experimental results for a carbon nanotube (CNT) based amplitude-modulated (AM) demodulator for modulation frequencies up to 100 kHz. Further, the CNT based demodulator was successfully demonstrated in an actual AM radio receiver operating at a carrier frequency of 1 GHz and capable of demodulating high-fidelity audio. The demodulation originates from the nonlinear current-voltage (IDS vs VDS) characteristic of the CNT, which induces rectification of a portion of the applied RF signal. By properly biasing the CNT such that the operating point is centered on the maximum nonlinear portion of the I-V curve, one can maximize the demodulation effect. This represents a simple application of carbon nanotubes and nanotechnology to the wireless realm. 相似文献
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《材料科学技术学报》2019,35(11):2447-2462
A single-wall carbon nanotube(SWCNT) has superior optical,electrical,and mechanical properties due to its unique structure and is therefore expected to be able to form flexible high-performance transparent conductive films(TCFs).However,the optoelectronic performance of these films needs to be improved to meet the requirements of many devices.The electrical resistivity of SWCNTTCFs is mainly determined by the intrinsic resistivity of individual SWCNTs and their junction resistance in networks.We analyze these key factors and focus on the optimization of SWCNTs and their networks,which include the diameter,length,crystallinity and electrical type of the SWCNTs,and the bundle size and interconnects in networks,as well as chemical doping and microgrid design.We conclude that isolated/small-bundle,heavily doped metallic or semiconducting SWCNTs with a large diameter,long length and high crystallinity are necessary to fabricate high-performance SWCNTTCFs.A simple,controllable way to construct macroscopic SWCNT networks with Y-type connections,welded junctions or microgrid design is important in achieving a low resistivity.Finally,some insights into the key challenges in the manufacture and use of SWCNT TCFs and their prospects are presented,hoping to shed light on promoting the practical application of SWCNT TCFs in future flexible and stretchable optoelectronics. 相似文献
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Carbon based conductive photoresist 总被引:1,自引:0,他引:1
Nina Hauptman Maša Žveglič Marijan Maček Marta Klanjšek Gunde 《Journal of Materials Science》2009,44(17):4625-4632
A conductive photoresist for photolithographic application was studied here. The negative near-UV sensitive epoxy-based photoresist
was used as a polymer matrix and conductive carbon black was used as functional filler. DC electrical resistivity of composite
as a function of filler concentration has a well-known S-shape. After UV-exposure the resistivity of the composite decreases
for almost five orders of magnitude, mostly at percolation threshold (approx. 0.6 vol.%). This effect can be attributed to
the fully cross-linked polymer structure formed during UV-exposure of the composite. The resistivity of prepared samples also
depend on the state of dispersion of the functional filler obtained using different dispersing additives. Composites with
better dispersed particles have lower resistivities. This effect remained below one order of magnitude and decreased after
UV-exposure. The composites with carbon black concentration of up to 1.1 vol.% are suitable for spin-coating and photolithography. 相似文献
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Hudanski L Minoux E Gangloff L Teo KB Schnell JP Xavier S Robertson J Milne WI Pribat D Legagneux P 《Nanotechnology》2008,19(10):105201
This paper describes a novel photocathode which is an array of vertically aligned multi-walled carbon nanotubes (MWCNTs), each MWCNT being associated with one p-i-n photodiode. Unlike conventional photocathodes, the functions of photon-electron conversion and subsequent electron emission are physically separated. Photon-electron conversion is achieved with p-i-n photodiodes and the electron emission occurs from the MWCNTs. The current modulation is highly efficient as it uses an optically controlled reconfiguration of the electric field at the MWCNT locations. Such devices are compatible with high frequency and very large bandwidth operation and could lead to their application in compact, light and efficient microwave amplifiers for satellite telecommunication. To demonstrate this new photocathode concept, we have fabricated the first carbon nanotube based photocathode using silicon p-i-n photodiodes and MWCNT bunches. Using a green laser, this photocathode delivers 0.5?mA with an internal quantum efficiency of 10% and an I(ON)/I(OFF) ratio of 30. 相似文献