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Sonication-Enhanced Alignment Relay Technique for the Orientation of Single-Walled Carbon Nanotubes
摘要： The high demand for thin, lightweight yet fast and e?cient devices is a driving force behind the miniaturization trend in the electronics industry. Speci?cally, the advancement of semiconducting single-walled carbon nanotubes (SWNTs) can continue to revolutionize transistors, although there are still many challenges ahead. We have previously reported an alignment relay technique (ART) that is capable of simultaneously controlling the alignment, length, and diameter of surface deposited SWNTs. However, the current technique yields inconsistencies in orientation, lengths of tubes, and their density. Here, we present a reviewed ART protocol that includes sonication for improved selectivity. We show that the SWNTs average alignment increased from 40% to 77% within a 10° range in orientation with sonication times as low as 5 min. Sonication generated larger diameter nanotubes on the surface, with a preference for semiconducting chiral tubes in the range of 1.44?1.61 nm in diameter. Consequently, simple alterations to the standard alignment relay technique can prove to be prosperous in improving selectivity and orientational control of single-walled carbon nanotubes. This work has direct impact for the simultaneous control of nanotube alignment and nanotube chiralities.
关键词： alignment relay technique,iptycenes,alignment,sonication,single-walled carbon nanotubes,surface chemistry,liquid crystals
更新于2025-09-16 10:30:52
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Fabrication of architectural structured polydopamine-functionalized reduced graphene oxide/carbon nanotube/PEDOT:PSS nanocomposites as flexible transparent electrodes for OLEDs
摘要： High performance, flexible transparent conductive films with a structure similar to that of reinforced concrete and constructed by sandwiching single-walled carbon nanotubes (SWCNT) between poly (3,4-ethylene dioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) and polydopamine functionalized reduced graphene oxide (PDA-RGO) were fabricated using simple spray coating. Mussel-inspired polydopamine was introduced as a graphene oxide reducing agent and modifier; the obtained PDA-RGO improved the interfacial adhesion between the conductive coating layers and substrate, and an effective post fabrication treatment method was performed on the hybrid film to achieve better conductivity. It was found that the resulting electrode exhibited a low sheet resistance of 52.2 Ω/sq. with a high optical transmittance of 88.7% at 550 nm. Moreover, the transparent film exhibited long-term stability with a relatively low roughness (ca. 2.41 nm), and its architectural structure sustained the flexibility of the film during bending. The organic light emitting diodes which using PDA-RGO/SWCNT/PEDOT:PSS film as anode was successfully fabricated, the luminance of the device was 2032 cd/cm2 at 15 V and the maximum current efficiency was 2.13 cd/A at 14 V, indicating the strong potential of this type of transparent electrode for flexible electroluminescent devices.
关键词： OLEDs,Polydopamine Functionalized Reduced Graphene Oxide,PEDOT:PSS,Flexible transparent conductive films,Carbon nanotubes
更新于2025-09-16 10:30:52
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Fine-tuning of spark-discharge aerosol CVD reactor for single-walled carbon nanotube growth: the role of ex situ nucleation
摘要： We report a development of recently designed apparatus equipped with a spark discharge generator of catalytic nanoparticles for robust aerosol CVD synthesis of single-walled carbon nanotubes. We achieve a profound control over the diameter distribution and the defectiveness of carbon nanotubes produced. By providing a justified comparison of the apparatus with the most abundant aerosol CVD reactor utilizing ferrocene as a catalyst precursor, we reveal the role of the activation procedure: while spark-discharge generator provides aerosol of nanoparticles (ex situ route), the ferrocene vapor decomposes in the nanotube growth zone providing an in situ formation of the catalyst. With other parameters being equal, we reveal the differences in the nanotube growth (diameter and length distribution, yield, defectiveness) employing a comprehensive set of methods (the analysis of differential mobility of the aerosol particles, optical spectroscopy, scanning and transmission electron microscopy, Raman spectroscopy, and atomic force microscopy). We show the ex situ activation in the spark discharge reactor to provide a lower utilization degree of the nanoparticles due to over-coagulation. However, the same method provides an independence of the key performance parameters of the nanotubes opening a room for scaling the apparatus.
关键词： spark-discharge generator,differential mobility analyzer,aerosol CVD synthesis,catalyst activation,floating catalyst,single-walled carbon nanotubes
更新于2025-09-16 10:30:52
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Polarized Raman imaging of large area aligned semiconducting single‐walled carbon nanotubes
摘要： The current method of characterizing single-walled carbon nanotube (SWCNT) alignment utilizes single-point measurements of a few hundred square nanometers of polarized Raman spectroscopy to characterize an entire substrate of SWCNTs on the order of square centimeters. In this study, we demonstrate a new polarized Raman spectroscopy analyzation technique of orientation Raman imaging that images areas as large as 1 mm2. This provides a significantly more accurate representation of the spatial distribution in the alignment of any SWCNT film by increasing the measured area by 10 orders of magnitude over previous standard characterization techniques. Furthermore, this creates an “easy-to-see” visual representation of alignment based on optical anisotropy values. Improving the efficiency of characterizing alignment in SWCNT films via polarized Raman spectroscopy is an important step toward manufacturing scalable films of aligned SWCNTs.
关键词： polarized Raman imaging,polarized Raman spectroscopy,orientation image,carbon nanotube alignment,carbon nanotubes
更新于2025-09-12 10:27:22
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Optical and Electrical Properties of Double-Walled Carbon Nanotube/Polyaniline Composite
摘要： Nanocomposites of polyaniline loaded with different weight-fractions of double-wall carbon nanotubes were fabricated by in situ polymerizations of the polyaniline in the presence of double-wall carbon nanotubes. The composition of the nanocomposites is examined by X-ray diffraction and scanning electron microscopy techniques. The functionality of the synthesized composites was studied by electrical conductivity and fluorescence analyses. The dc conductivity of polyaniline was increased by introducing 2.5 wt% of DWCNTs into polyaniline matrix. The fluorescence emission from the double-wall carbon nanotubes/polyaniline showed a broad emission range in the visible region between 350 and 560 nm with appreciable enhancement in the intensity at 434 nm.
关键词： Polyaniline,Conductivity,Fluorescence,Double-wall carbon nanotubes,Composite
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) - Seoul, Korea (South) (2019.1.27-2019.1.31)] 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) - Development of a Highly Stretchable Strain Sensor Based on Patterned and Rolled Carbon Nanotubes
摘要： This paper reports a highly stretchable strain sensor consisting of patterned and rolled carbon nanotubes (CNTs) embedded in an elastomer. To form overlapped lines of CNTs on the elastomer, vertically aligned CNTs (VACNTs) are grown on the patterned catalytic sites and rolled out by a roller. In the initial unloaded state, these lines of CNTs are overlapped with each other. Under loading, the flexible substrate is extended, and the overlapped CNT lines are slid and separated, increasing the electrical resistance. The fabricated sensor showed excellent sensing performances including broad sensing range (>500% strain), high sensitivity (gauge factor >28), high repeatability, and durability. In addition, since the shape of the CNT lines determines the resistance through the deformed lines of CNTs under applied strain, the performance of the sensor can be further improved by optimizing the pattern design. Therefore, the sensor would be an attractive candidate for diverse applications of strain sensors.
关键词： high sensitivity,elastomer,stretchable strain sensor,carbon nanotubes,broad sensing range
更新于2025-09-12 10:27:22
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Carbon nanotube color centers in plasmonic nanocavities: A path to photon indistinguishability at telecom bands
摘要： Indistinguishable single photon generation at telecom wavelengths from solid-state quantum emitters remains a significant challenge to scalable quantum information processing. Here we demonstrate efficient generation of indistinguishable single photons directly in the telecom O-band from aryl-functionalized carbon nanotubes by overcoming the emitter quantum decoherence with plasmonic nanocavities. With an unprecedented single-photon spontaneous emission time down to 10 ps (from initially 0.7 ns) generated in the coupling scheme, we show a two-photon interference visibility at 4 K reaching up to 0.79, even without applying post selection. Cavity-enhanced quantum yields up to 74% and Purcell factors up to 415 are achieved with single-photon purities up to 99%. Our results establish the capability to fabricate fiber-based photonic devices for quantum information technology with coherent properties that can enable quantum logic.
关键词： Plasmonic nanocavities,indistinguishable single photons,telecommunication bands,carbon nanotubes
更新于2025-09-12 10:27:22
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Influence of single-walled carbon nanotubes induced exciton dissociation improvement on hybrid organic photovoltaic devices
摘要： Torch-plasma-grown single-walled carbon nanotubes (SWCNTs) are integrated with regioregular poly(3-hexylthiophene) (P3HT) and a fullerene derivative 1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C61 (PCBM) as a hybrid photoactive layer for bulk heterojunction solar cell devices. We demonstrate that molecular information could be accurately obtained by time-of-flight secondary ion mass spectrometry through the hybrid organic photoactive solar cell layers when sputtering is performed using a Cs+ 2000 eV ion source. Furthermore, the photovoltaic (PV) performance of the fabricated devices show an increase in the short-circuit current density (Jsc) and the fill factor (FF) as compared to the pristine devices fabricated without SWCNTs. The best results are obtained with 0.5 wt. % SWCNT loads, where an open-circuit voltage (VOC) of 660 mV is achieved, with a Jsc of 9.95 mA cm?2 and a FF of 54%, leading to a power conversion efficiency of 3.54% (measured at standard test conditions, AM1.5 g). At this optimum SWCNT concentration of 0.5 wt. %, and to further understand the charge-transfer mechanisms taking place at the interfaces of P3HT:PCBM:SWCNT, Jsc is measured with respect to the light intensity and shows a linear dependency (in the double logarithmic scale), which implies that losses in the charge carrier are rather governed by monomolecular recombination. Finally, our results show that our hybrid devices benefit from the fullerene electron accepting nature and from the SWCNT fast electron transportation feature that improve substantially the exciton dissociation efficiency. The influence of the SWCNTs on the Fermi level and the work function of the photoactive composite and its impact on the PV performance is also investigated.
关键词： single-walled carbon nanotubes,bulk heterojunction,PCBM,hybrid organic photovoltaic devices,photovoltaic performance,P3HT,exciton dissociation
更新于2025-09-12 10:27:22
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Interfacial Engineering in Functional Materials for Dye‐Sensitized Solar Cells || Carbon Nanotubes‐Based Nanocomposite as Photoanode
摘要： Over the past few decades, energy is the backbone of technology and economic development. In addition to man, machine, and money, energy is now fourth factor of production. Without energy, no machine will run, electricity is needed for everything. Hence, our energy requirements have increased dramatically in the years following the industrial revolution. Readily accessible fossil fuels, such as coal, natural gas, and oils, are the major energy sources used to meet our current need. However, these sources are nonrenewable and have led to serious environmental issues, global warming, and air pollution, and their increasing consumption rate has accelerated fossil fuel depletion; the search for alternative energy source has become vital.
关键词： Dye-Sensitized Solar Cells,Photoanode,Renewable Energy,Nanocomposite,Carbon Nanotubes
更新于2025-09-12 10:27:22
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Adhesion of Single-walled Carbon Nanotube Thin Films with Different Materials
摘要： Single-walled carbon nanotubes (SWCNTs) possess extraordinary physical and chemical properties. Thin films of randomly oriented SWCNTs have great potential in many opto-electro-mechanical applications. However, good adhesion of SWCNT films with a substrate material is pivotal for their practical use. Here, for the first time we systematically investigate the adhesion properties of SWCNT thin films with commonly used substrates such as glass (SiO2), indium tin oxide (ITO), crystalline silicon (C-Si), amorphous silicon (a-Si:H), zirconium oxide (ZrO2), platinum (Pt), polydimethylsiloxane (PDMS), and SWCNTs for self-adhesion using atomic force microscopy. By comparing the results obtained in air and inert Ar atmospheres we observed a great contribution of the surface state of the materials on their adhesion properties. We found that the SWCNT thin films have higher adhesion in an inert atmosphere. The adhesion in the air can be greatly improved by a fluorination process. Experimental and theoretical analyses suggest that adhesion depends on the atmospheric conditions and surface functionalization.
关键词： adhesion energy,inert atmosphere,Single-walled carbon nanotubes,fluorination,ambient conditions,thin films
更新于2025-09-12 10:27:22