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Dewu Lin Ying Zhou Kazufumi Kobashi Guohai Chen Don N. Futaba Kenji Hata 《Advanced functional materials》2023,33(8):2211180
Despite 30-year development of carbon nanotube (CNT) based materials, harnessing the outstanding nanoscale properties of individual CNT for macroscale applications remains challenging. High specific surface area, a crucial feature of CNTs, often suffers from the formation of tightly packed bundles with inaccessible “dead space”. Herein, a novel “microwave shock” approach to open the “dead space” trapped within bundles is reported. Employing N2 ambient during microwave irradiation, CNT bundles undergo an efficient structural alteration and interfacial modification simultaneously due to the strong radiative coupling, while the graphitic structure remains undamaged. In this way, a 15-fold increase (from 42 to 648 m2 g−1) in the interstitial surface area as well as the lithiophilic functionalization (≈1 atom% nitrogen doping) are achieved without the degradation of other properties. Furthermore, to highlight the merits of this microwave shock process, the treated CNT films are applied as a host material for the anode in a lithium metal battery and demonstrate the suppression of dendritic lithium growth and improve cycling stability. This microwave shock approach provides an efficient avenue to modify nanocarbon-based materials for further applications. 相似文献
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Lightweight aerogels with large specific surface area (SSA) have numerous applications. Free‐standing aerogels are created from single‐walled carbon nanotubes (SWCNTs), and their SSA and pore characteristics, electrical conductivity, mechanical properties, and thermal management attributes are determined. The SSA of the aerogels is extraordinarily high and approaches 1291 m2 g?1 at a density of 7.3 mg mL?1, which is close to the theoretical limit (≈1315 m2 g?1). Mechanical characterization shows that these aerogels have open‐cell structures and their Young's moduli are higher than other aerogels at comparable density. The aerogels also enhance heat transfer in a forced convective process by ≈85%, presumably due to their large porosity and surface area. 相似文献
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Tamara Druzhinina Stephanie Hoeppener Ulrich S. Schubert 《Advanced functional materials》2009,19(17):2819-2825
The microwave (MW)‐assisted synthesis of one dimensional carbon systems is introduced as a promising approach to improve the speed and cost‐effectiveness of the fabrication process. Improved reaction conditions are generated by direct MW heating and synthesis under advanced reaction conditions. The influence of the reaction conditions is investigated and the importance of individual process parameters on the synthesis is discussed. Temperature and pressure data recorded during the irradiation process are analyzed in detail and allow the determination of essential process parameters. This leads to improved reaction conditions, better control of the one‐dimensional carbon nanosystems by tuning the catalyst materials, and allows expanding this approach to initiate the synthesis on a variety of different substrates, such as quartz glass and mica. 相似文献
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Chandrani Pramanik Tariq Jamil Jacob R. Gissinger Darice Guittet Pedro J. Arias‐Monje Satish Kumar Hendrik Heinz 《Advanced functional materials》2019,29(50)
Polyacrylonitrile (PAN) is among the most promising precursor polymers to produce strong and lightweight carbon fiber. Conformations in solution and the extent of binding to carbon nanotubes (CNTs) are critical during gel spinning and for alignment of graphitic layers upon carbonization. Here, quantitative insights into these processes are reported using molecular dynamics simulations at the atomic scale including virtual π electrons and comparisons to experimental data. Common solvents for fiber spinning induce significant differences in PAN conformation in dilute solutions at 25 °C with persistence lengths between 0.5 and 2 nm. Variations in conformation become smaller at 75 °C, in the presence of CNTs, and at higher PAN concentration. “Aging” of PAN conformations in dimethylformamide and dimethylsulfoxide at higher temperature is explained and a correlation between extended polymer conformations and increased binding to CNTs is identified in dilute solutions. PAN is overall barely attracted to CNTs under common solution conditions and enters significant surface contact only at higher concentration as solvent is physically removed. The impact of temperature is small, whereby binding increases at lower temperatures. The results provide guidance to control interactions of polymers with CNTs to induce distinct conformations and specific binding at the early stages of assembly. 相似文献
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Christine H. J. Kim Dandan Zhao Gyeonghee Lee Jie Liu 《Advanced functional materials》2016,26(27):4976-4983
Designing macroscopic, 3D porous conductive materials with high mechanical strength is of great importance in many fields, including energy storage, catalysis, etc. This study reports a novel approach to fabricate polyaniline‐coated 3D carbon x‐aerogels, a special type of aerogels with mechanically strong, highly cross‐linked structure that allows the originally brittle aerogels machinable. This approach is accomplished by introducing a small amount of graphene into the sol–gel process of resorcinol and formaldehyde, followed by physical activation and subsequent cross‐linking with polyaniline via electropolymerization. The resulting x‐aerogels are not only porous and conductive, but also mechanically robust with high compressibility and fast recovery. The strong combination of these properties makes the x‐aerogels promising for high performance supercapacitors that are designed to provide additional functionality for wearable and portable electronics. Such multi‐functionality leads to a significant increase in electrochemical performance, in particular high volumetric capacitance, which results from the more densely packed electroactive structure in three dimensions. More importantly, monoliths of carbon x‐aerogels are machinable into thin slices without losing their properties, thus enabling effective integration into devices with different sizes and shapes. 相似文献
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Thin Films: 2D Janus Hybrid Materials of Polymer‐Grafted Carbon Nanotube/Graphene Oxide Thin Film as Flexible,Miniature Electric Carpet (Adv. Funct. Mater. 16/2015) 
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下载免费PDF全文 Peng Xiao Changjin Wan Jincui Gu Zhenzhong Liu Yonghong Men Youju Huang Jiawei Zhang Liqiang Zhu Tao Chen 《Advanced functional materials》2015,25(16):2479-2479
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Peng Xiao Changjin Wan Jincui Gu Zhenzhong Liu Yonghong Men Youju Huang Jiawei Zhang Liqiang Zhu Tao Chen 《Advanced functional materials》2015,25(16):2428-2435
Ultrathin, freestanding polymer hybrid film with macroscopic sizes and molecular thicknesses have received significant interest due to their applications as functional devices, microsensors or nanoactuators. Herein, a 2D Janus hybrid of polymer‐grafted carbon nanotubes/graphene oxide (CNTs/GO) thin film is fabricated using microcontact printed CNTs/GO as photo active surface to grow polymer brushes by self‐initiated photografting and photopolymerization selectively from one side of CNTs/GO film. This achieved 2D Janus hybrid materials with grafted polymer layer as insulative carpet and supported CNTs/GO thin film as conductive element have the potential application as flexible and miniature electric carpet for heating micro‐/nano devices locally. 相似文献
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Wytse Talsma Aprizal Akbar Sengrian Jorge Mario Salazar‐Rios Herman Duim Mustapha Abdu‐Aguye Stefan Jung Sybille Allard Ullrich Scherf Maria Antonietta Loi 《Advanced Electronic Materials》2019,5(8)
In the past years, high‐quality semiconducting single‐walled carbon nanotube (s‐SWCNT) inks obtained by conjugated polymer wrapping using toluene as solvent have been used for the fabrication of high‐performance field‐effect transistors. Charge‐carrier mobilities up to 50 cm2 V−1 s−1 and on/off ratios above 108 have been reported for devices based on networks of s‐SWCNT. However, devices fabricated from inks that are only a few weeks old generally show a marked decrease in performance, indicating the limited shelf life of toluene‐based inks. The use of o‐xylene as applicator solvent to obtain high quality and very stable s‐SWCNT inks is reported. The charge carrier mobility of field‐effect transistors fabricated with this new ink show a twofold increase in magnitude compared to devices prepared from a toluene solution. More importantly, the device‐to‐device performance shows improved reproducibility, which is ascribed to the higher degree of homogeneity of the s‐SWCNT network deposited from o‐xylene with respect to the one from toluene. Finally, the o‐xylene inks maintain their initial properties for longer than one year. This very long shelf life is an important pre‐condition for the industrial use of s‐SWCNT inks. 相似文献
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Temperature‐Dependent Electrical Transport in Polymer‐Sorted Semiconducting Carbon Nanotube Networks 下载免费PDF全文
下载免费PDF全文 The temperature dependence of the electrical characteristics of field‐effect transistors (FETs) based on polymer‐sorted, large‐diameter semiconducting carbon nanotube networks is investigated. The temperature dependences of both the carrier mobility and the source‐drain current in the range of 78 K to 293 K indicate thermally activated, but non‐Arrhenius, charge transport. The hysteresis in the transfer characteristics of FETs shows a simultaneous reduction with decreasing temperature. The hysteresis appears to stem from screening of charges that are transferred from the carbon nanotubes to traps at the surface of the gate dielectric. The temperature dependence of sheet resistance of the carbon nanotube networks, extracted from FET characteristics at constant carrier concentration, specifies fluctuation‐induced tunneling as the mechanism responsible for charge transport, with an activation energy that is dependent on film thickness. Our study indicates inter‐tube tunneling to be the bottleneck and implicates the role of the polymer coating in influencing charge transport in polymer‐sorted carbon nanotube networks. 相似文献
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The effects of incorporating functionalized multiwall carbon nanotubes with polystyrene (PSMWCNTs) in organic polymer solar cells were studied. Different concentrations of carbon nanotubes in poly(2-methoxy-5-(2-ethyhexyl-oxy)-p-phenylenevinylene) [MEH-PPV] were investigated via absorption spectroscopy, photoluminescence (PL) and current–voltage measurements under illumination, in order to determine the photovoltaic effect of the elaborated organic solar cells. The decrease in PL intensity with the progressive addition of PSMWCNTs is a signature of an effective charge transfer at MEH-PPV/PSMWCNTs heterojunction. Moreover, the addition of carbon nanotubes (CNTs) to the polymer increases the power conversion efficiency compared with the device with pristine polymer. A critical concentration value of 0.15 wt% of PSMWCNTs is found to achieve the best performance of devices. Direct current conductivity of the composite film was found to increase rapidly with the increase in PSMWCNTs concentration. The enhancement in conductivity is explained in terms of percolation theory with an estimated percolation threshold of 0.092 wt%. 相似文献
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SWCNT network morphology and TFT performance of polyfluorene wrapped sc-SWCNT on different substrates is reported. The polymer/tube weight ratio and concentration impacts network formation and device performance. Hydrophilic SiO2 surfaces show stronger adsorption compared to poly-l-lysine treated SiO2, which leads to more uniform and higher density networks. TFTs with mobility up to 38 cm2/Vs with <10% variability and on/off ratios on the order of 105 were obtained using an iterative dip-coating process. 相似文献
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50～650℃加热与干燥设备,国外以热风炉国内以远红外炉为主。从传热学原理,本文提出了一新型加热炉——低温辐射炉。各项性能指标均优越于热风炉。同时指出远红外炉存在的问题及其改进方法。 相似文献
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A microwave‐induced controlled method for the purification of single‐walled carbon nanotubes (SWCNTs) by removing residual metal catalysts and carbonaceous impurities is reported. Compared to conventional strong acid treatment, this one‐step method uses dilute acids and complexing agents and reduces the reaction times to the order of minutes. Furthermore, the SWCNTs retain their chemical and physical properties and are not functionalized. Electron microscopy, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and atomic absorption (AA) spectrometry studies were used to characterize the purified SWCNTs. 相似文献
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Qinyuan Jiang Fei Wang Run Li Xueke Wu Wenshuo Zhang Siming Zhao Ya Huang Baoshun Wang Shiliang Zhang Yanlong Zhao Rufan Zhang 《Advanced functional materials》2023,33(10):2212665
Ultralong carbon nanotubes (CNTs) are believed to be ideal candidates for various high-end applications because of their macroscale lengths, perfect structures, and excellent mechanical and electrical properties. The key to the wide application of ultralong CNTs is their controlled synthesis and mass production. Ultralong CNTs usually follow a flying kite-like growth mechanism, during which process there exists a thermal buoyancy that keeps ultralong CNTs floating in the gas flow. However, it remains vague for a long time about the origin of this thermal buoyancy. Herein, a simple and quantitative heat balance model is proposed to describe the inherent thermal effect of substrates, which explains the origin of the temperature difference between the substrate and the gas flow. The inherent thermal effect is found to be positively correlated with the emissivity of the substrates. Then, the local temperature gradient induced by the inherent thermal effect is found to result in both natural convection and thermophoresis. Thermophoretic force is proven to be the dominant driving force for lifting the ultralong CNTs up from the substrates. By utilizing the inherent thermal effect and designing the local temperature distribution, the areal density and orientation of ultralong CNT arrays are modulated. 相似文献
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Nitrogen‐doped carbon aerogels (NCAs) have received great attention for a wide range of applications, from thermal electronics to waste water purification, heavy metal or gas adsorption, energy storage, and catalyst supports. Herein NCAs are developed via the synthesis of a Schiff‐base porous organic polymer aerogel followed by pyrolysis. By controlling the pyrolysis temperature, the polymer aerogel can be simply converted into porous NCAs with a low bulk density (5 mg cm?3), high surface area (2356 m2 g?1), and high bulk porosity (70%). The NCAs containing 1.8–5.3 wt% N atoms exhibit remarkable CO2 uptake capacities (6.1 mmol g?1 at 273 K and 1 bar, 33.1 mmol g?1 at 323 K and 30 bar) and high ideal adsorption solution theory selectivity (47.8) at ambient pressure. Supercapacitors fabricated with NCAs display high specific capacitance (300 F g?1 at 0.5 A g?1), fast rate (charge to 221 F g?1 within only 17 s), and high stability (retained >98% capacity after 5000 cycles). Asymmetric supercapacitors assembled with NCAs also show high energy density and power density with maximal values of 30.5 Wh kg?1 and 7088 W kg?1, respectively. The outstanding CO2 uptake and energy storage abilities are attributed to the ultra‐high surface area, N‐doping, conductivity, and rigidity of NCA frameworks. 相似文献
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Jing Wang Dengsen Yuan Peiying Hu Yongjiang Wang Jin Wang Qingwen Li 《Advanced functional materials》2023,33(32):2300441
Silica aerogels, a type of porous material featuring extra low density and thermal conductivity, have drawn increasing interest from both academia and industry owing to their excellent thermal insulation performance. However, thermal insulation is always the single consideration when silica aerogels are used for thermal management. In this study, the on-demand thermal management (ODTM) of silica aerogel with either passive thermal insulation, passive heating, or passive cooling in different environments is revealed. The ODTM behavior of silica aerogels can be simply fulfilled through their optical property variations such as solar light transparency and infrared emissivity, which are controllable via the microstructures of the building blocks and surface composition design. Robust solar heating of 25 °C higher than the ambient in the daytime and sub-ambient cooling of 7 °C at night is achieved with the traditional transparent silica aerogel. Interestingly, sub-ambient cooling of 5 °C in the daytime and a warmer state on cold nights is achieved by modifying its solar transmittance and infrared emissivity. This study guides a comprehensive understanding of the thermal management behavior of silica aerogels and leads to ODTM applications of silica aerogels by tailoring their optical and thermal conductivity properties. 相似文献