Deposition Of Carbon Nanotubes Research Articles

Spray-lithography of hybrid graphene-perovskite paper-based photodetectors for sustainable electronics

Paper is an ideal substrate for the development of flexible and environmentally sustainable ubiquitous electronic systems. When combined with nanomaterial-based devices, it can be harnessed for various Internet-of-Things applications, ranging from wearable electronics to smart packaging. However, paper remains a challenging substrate for electronics due to its rough and porous nature. In addition, the absence of established fabrication methods is impeding its utilization in wearable applications. Unlike other paper-based electronics with added layers, in this study, we present a scalable spray-lithography on a commercial paper substrate. We present a non-vacuum spray-lithography of chemical vapor deposition (CVD) single-layer graphene (SLG), carbon nanotubes (CNTs) and perovskite quantum dots (QDs) on a paper substrate. This approach combines the advantages of two large-area techniques: CVD and spray-coating. The first technique allows for the growth of SLG, while the second enables the spray coating of a mask to pattern CVD SLG, electrodes (CNTs), and photoactive (QDs) layers. We harness the advantages of perovskite QDs in photodetection, leveraging their strong absorption coefficients. Integrating them with the graphene enhances the photoconductive gain mechanism, leading to high external responsivity. The presented device shows high external responsivity of ∼520 A W−1 at 405 nm at <1 V bias due to the photoconductive gain mechanism. The prepared paper-based photodetectors (PDs) achieve an external responsivity of 520 A W−1 under 405 nm illumination at <1 V operating voltage. To the best of our knowledge, our devices have the highest external responsivity among paper-based PDs. By fabricating arrays of PDs on a paper substrate in the air, this work highlights the potential of this scalable approach for enabling ubiquitous electronics on paper.

Carbon nanotube-induced localized laser heating toward simultaneously enhanced laydown efficiency and fracture toughness of in-situ consolidated glass fiber thermoplastic composites

Thermoplastic composites suffer from weak inter-tape bonding during high-rate laser-assisted automated fiber placement (L-AFP). Here, we propose a strategy to simultaneously enhance the laser heating efficiency and fracture toughness of glass fiber-reinforced polypropylene prepreg tape for L-AFP process by depositing carbon nanotubes (CNTs) on the tape surface by a low-cost bath coating process. CNTs function as efficient light absorbing and photothermal coating to promote molecular inter-diffusion and interfacial healing between successive tapes, as well as toughen the weak interface by CNT pull-out and rupture. A 56 % increase in the near-infrared laser absorption of tapes results in a 946 % improvement in the laydown rate. CNTs also remarkably improve transverse temperature uniformity. Furthermore, double cantilever beam and pants tearing tests show that 0.5 wt% CNTs improve the mode I interlaminar fracture toughness and mode III fracture strength by 17 % and 52 %, respectively, attributed to the enhanced molecular inter-diffusion and CNT bridging effect.

Towards a mechanistic understanding of the floating catalyst CVD of CNTs: Interplay between catalyst particle nucleation, growth and deactivation

The chemical vapor deposition (CVD) of carbon nanotubes (CNTs) with the floating catalyst technique, using ferrocene as catalyst, is computationally investigated from its mechanistic perspective. The present work presents a novel model dealing with the phenomena taking place in the bulk of a floating catalyst CVD reactor. The developed model incorporates the gas flow, heat transfer and species transport phenomena, coupled with reaction mechanisms and kinetics, as well as the catalyst particle formation and growth dynamics. The novelty of the approach lies on the inclusion of carbon species deposition on the catalyst particle surface, which have a crucial effect on the particle growth and catalyst deactivation, leading to the termination of CNT growth on the particles. The model predictions are directly compared with experimental results from the literature for the same process and for a range of process parameters, showing a very good agreement. The computational model not only successfully predicts the experimental behavior but also reveals the effect of individual mechanisms on the inhibition of particle growth, catalyst deactivation and CNT growth. In this way, the model provides an in-depth mechanistic understanding of the mechanisms in the reactor bulk, which is currently missing, thus paving the way towards the knowledge-based process design and optimization and the possibility of using more sustainable or environmentally-friendly precursors and catalysts which have not been studied experimentally in detail.

Production of Stable Electrically Conductive PVDF Membranes Based on Polydopamine-Polyethyleneimine-Assisted Deposition of Carbon Nanotubes.

Electrically conductive membranes (ECMs) have emerged as a multifunctional separation technology that integrates membrane filtration with electrochemical reactions. Physical stability remains a critical challenge for ECMs synthesized by coating polymer membranes with conductive materials. In this article, polydopamine (PDA) and polyethyleneimine (PEI) were used to facilitate the synthesis of significantly more stable ECMs using poly(vinylidene fluoride) (PVDF) ultrafiltration membranes and carbon nanotubes (CNTs). Four different synthesis methods were compared in terms of the final surface stability and separation properties: (1) CNTs deposited on PEI-crosslinked PDA-coated PVDF membranes, (2) PEI-crosslinked CNTs deposited on PDA-coated PVDF, (3) PDA, PEI and CNTs sequentially deposited layer-by-layer on PVDF, and (4) PEI-crosslinked PDA deposited on CNT-coated PVDF. The results revealed that method 1 generated ECMs with the greatest physical stability, highest electrical conductivity (18,518 S/m), and sufficient permeability (395.2 L/(m2·h·bar). In comparison, method 2 resulted in membranes with the highest permeability (2128.5 L/(m2·h·bar), but with low surface conductivity (502 S/m) and poor physical stability (i.e., 53-75% lower peel-off forces compared to other methods). Overall, methods 1, 3, and 4 can be used to make highly conductive membranes with a 97-99% removal of methyl orange by electrochemical degradation at -3 V.

Wear behavior and corrosion resistance of laser-clad Ni60-1 % carbon nanotubes coating

Carbon nanotubes (CNTs) can improve the performance of composite coatings as reinforcing powders due to their three-dimensional (3D) tubular structure and good self-lubricating properties. Unfortunately, CNTs are difficult to mix uniformly with other powders due to their extremely light mass and fragile microstructure. Therefore, in this study, the alcohol-stirring mixing method was used for powder mixing. The results showed that Ni60 powder and 1 wt% CNTs were mixed homogeneously by this method, and large-area CNTs deposition was achieved on the surface of Ni60 powder. The properties of the Ni60/CNTs coatings fabricated by laser cladding (LC) were examined. The microstructure of the Ni60/CNTs coating was refined, and M23C6 carbides were generated. Compared with the Ni60 coating, the microhardness of the Ni60/CNTs coating increased by 41.6 %, and the wear rate decreased by 76.76 %. The improvement is mainly due to the excellent self-lubricating properties of CNTs and their tubular structure, which improves the friction behavior of the coating. In addition, the refinement of microstructure and the generation of C23C6 carbides also play an enhanced role. The bridging of the tubular structure of CNTs and the filling effect of carbides resulted in improved corrosion resistance of the Ni60/CNTs coatings.

Parameters controlling the electrokinetic deposition of multi-walled carbon nanotubes as biosensing thin films

Parameters controlling the electrokinetic deposition of multi-walled carbon nanotubes as biosensing thin films

Reactivity of the Ethenium Cation (C2H5+) with Ethyne (C2H2): A Combined Experimental and Theoretical Study.

The gas-phase reaction between the ethyl cation (C2H5+) and ethyne (C2H2) is re-investigated by measuring absolute reactive cross sections (CSs) and branching ratios (BRs) as a function of collision energy, in the thermal and hyperthermal energy range, via tandem-guided ion beam mass spectrometry under single collision conditions. Dissociative photoionization of C2H5Br using tuneable VUV radiation in the range 10.5-14.0 eV is employed to generate C2H5+, which has also allowed us to explore the impact of increasing (vibrational) excitation on the reactivity. Reactivity experiments are complemented by theoretical calculations, at the G4 level of theory, of the relative energies and structures of the most relevant stationary points on the reactive potential energy hypersurface (PES) and by mass-analyzed ion kinetic energy (MIKE) spectrometry experiments to probe the metastable decomposition from the [C4H7]+ PES and elucidate the underlying reaction mechanisms. Two main product channels have been identified at a centre-of-mass collision energy of ∼0.1 eV: (a) C3H3++CH4, with BR = 0.76±0.05 and (b) C4H5++H2, with BR = 0.22±0.02. A third channel giving C2H3+ in association with C2H4 is shown to emerge at both high internal excitation of C2H5+ and high collision energies. From CS measurements, energy-dependent total rate constants in the range 4.3×10-11-5.2×10-10 cm3·molecule-1·s-1 have been obtained. Theoretical calculations indicate that both channels stem from a common covalently bound intermediate, CH3CH2CHCH+, from which barrierless and exothermic pathways exist for the production of both cyclic c-C3H3+ and linear H2CCCH+ isomers of the main product channel. For the minor C4H5+ product, two isomers are energetically accessible: the three-member cyclic isomer c-C3H2(CH3)+ and the higher energy linear structure CH2CHCCH2+, but their formation requires multiple isomerization steps and passages via transition states lying only 0.11 eV below the reagents' energy, thus explaining the smaller BR. Results have implications for the modeling of hydrocarbon chemistry in the interstellar medium and the atmospheres of planets and satellites as well as in laboratory plasmas (e.g., plasma-enhanced chemical vapor deposition of carbon nanotubes and diamond-like carbon films).

Half‐Full Filled Aerogels with a 348% Increment in Energy Absorption and a Retained High Electromagnetic Shielding Performance

AbstractAerogels, as kinetic energy absorbing materials, can find crucial applications for safeguarding in transportation, sports, buildings, construction, and aerospace. However, the highly porous structure makes it extremely fragile for endurance usage. In this study, a half‐full filled structure has been proposed, and the concept has been demonstrated based on shear thickening fluid (STF) and chemically vapor deposited carbon nanotube aerogels (CNTAs), in which the outer part of CNTA is filled with STF while the inner core keeping unfilled. Chemical vapor deposition significantly enhances the elasticity and electromagnetic shielding performance of the native CNTA. The half‐full filled aerogels (HFFA) show a 348% increase in energy absorption compared to the CNTA. At the same time, the density, electronic conductivity, and electromagnetic interference shielding effectiveness (EMI SE) of the HFFAs are 0.117 g cm−3, 1213 S m−1, and 69.52 dB (which is a neglectable reduction of 0.63% compared to native CNTA), respectively. The HFFA strategy provides an alternative route to fabricate robust aerogels with a remarkable increase of target properties while maintaining other properties, such as low density, high pore volume, and conductivity, with limited changes.

Photophoretic deposition and separation of aerosol-synthesized single-walled carbon nanotubes

We report a novel, dry, and clean method to directly deposit single-walled carbon nanotubes (SWCNTs) onto a desired substrate with the photophoresis phenomenon. We demonstrate the photophoresis method to be convenient and reproducible to deposit low-bundled nanotubes to form either non-percolating or continuous networks with controlled SWCNT density and surface distribution. Employing the structure-dependent optical features of the nanotubes, we show the correlation between the light source spectrum and the configuration of the deposited SWCNTs due to the selective light interaction with SWCNTs of certain chiralities. Thus, photophoretic deposition is a promising method for the fabrication of various advanced devices, such as electrically driven single-photon emitters or field-effect transistors from semiconducting SWCNTs with a desired electronic structure.

Empirical Analysis of Multiwalled Carbon Nanotube Deposition for Enhancing Mechanical and Tribological Characteristics in Aluminium-Based Metal Matrix Composites

Empirical Analysis of Multiwalled Carbon Nanotube Deposition for Enhancing Mechanical and Tribological Characteristics in Aluminium-Based Metal Matrix Composites

Electrophoretic Deposition of Multi-Walled Carbon Nanotube Coatings on CoCrMo Alloy for Biomedical Applications.

Carbon nanotubes are a promising material for use in innovative biomedical solutions due to their unique chemical, mechanical, electrical, and magnetic properties. This work provides a method for the development of ultrasonically assisted electrophoretic deposition of multi-walled carbon nanotubes on a CoCrMo dental alloy. Functionalization of multi-walled carbon nanotubes was carried out by chemical oxidation in a mixture of nitric and sulfuric acids. The modified and unmodified multi-walled carbon nanotubes were anaphoretically deposited on the CoCrMo alloy in an aqueous solution. Chemical composition was studied by Fourier transform infrared spectroscopy. Surface morphology was examined by scanning electron microscopy. The mechanism and kinetics of the electrochemical corrosion of the obtained coatings in artificial saliva at 37 °C were determined using the open-circuit potential method, electrochemical impedance spectroscopy, and anodic polarization curves. The capacitive behavior and high corrosion resistance of the tested electrodes were revealed. It was found that the kinetics of electrochemical corrosion of the CoCrMo electrode significantly decreased in the presence of the functionalized multi-walled carbon nanotube coating. Electrophoretic deposition was shown to be an effective, low-cost, and fast method of producing nanotubes with controlled thickness, homogeneity, and packing density.

The effect of electrophoretic deposition of carbon nanotubes on carbon fiber on interfacial properties of the thermoplastic polyimide composite

In order to improve the interfacial properties of carbon fiber/polyimide (CF/PI) composite, silanization reaction carbon nanotubes (CNTs) were introduced to the surface of carbon fiber by electrophoretic deposition to prepare CF/CNT/PI composite. The effects of carbon fiber surface treatment on the mechanical properties of the composites were studied. The results showed that the interlaminar shear strength and bending strength of the composite materials were increased by 11% and 9%, respectively. The scanning electron microscope and Atomic Force Microscope (AFM) was used to analyze the fine structure of composite interface phase. The results show that the introduction of CNTs creates an interface transition layer of CNTs reinforced PI resin between the fiber and the matrix.

Scalable, roll-to-roll manufacturing of multiscale nanoparticle/fiber composites using electrophoretic deposition: Novel multifunctional in situ sensing applications

Multiscale composites, where traditional fiber reinforcements are combined with nanoscale reinforcements, have emerged as multifunctional materials and have found potential for in situ strain and damage sensing, and energy harvesting/storage applications. Critical to the advancement of future applications is the development of manufacturing techniques that are industrially scalable. Electrophoretic deposition (EPD) can uniformly coat functionalized nanoparticles, such as carbon nanotubes (CNT), on conductive and non-conductive fiber substrates, producing multiscale composites with controlled microstructures and functional properties. In this research, a pilot-scale roll-to-roll EPD system is developed to continuously manufacture CNT-integrated fabrics for in situ sensing applications. Based on fundamental knowledge of CNT deposition mechanisms, key experiments are conducted to determine electrode configurations to optimize deposition yield in the roll-to-roll process. Functionalized CNTs are then deposited on 4–6 m long continuous rolls of randomly oriented non-woven glass fiber veil with different areal weights, and the CNTs form a continuous, conductive fiber-level coating. The thin and open fabric microstructure allows embedded sensors that are minimally invasive to the composite structure and allow ultraviolet (UV) light transmittance for use with UV-curable resins. The electrically conductive CNT network created on the fabric allows for the integration of sensing functionality. Short beam specimens with the CNT sensors embedded at the midplane showed no deterioration in strength. Multiple functionalities, including strain sensing and flow/UV cure monitoring during vacuum infusion are demonstrated. Sensors tested under flexural loading demonstrated sensitivity in tension and compression, and during resin infusion, the sensors could track resin flow and cure progression.

Stretchable hybrid platform‐enabled interactive perception of strain sensing and visualization

AbstractHuman–machine interactive platforms that can sense mechanical stimuli visually and digitally are highly desirable. However, most existing interactive devices cannot satisfy the demands of tactile feedback and extended integration. Inspired by the mechanoluminescence (ML) function of cephalopod skin and the sensitive perception of microcracked slit‐organs, a bioinspired stretchable interactive platform is developed by designing a stretchable poly(styrene‐block‐butadiene‐block‐styrene)/fluorescent molecule (SFM) composite followed by the in situ polymerization of pyrrole (Py) and deposition of carbon nanotubes (CNTs), which possesses a simple multilayered structure and quantitatively senses the applied strains via the variations of digital electrical resistance and visual fluorescence intensity. Using the strain‐dependent microstructures derived from the synergistic interactions of the rigid PPy/CNTs functional layer and SFM, the SFM/PPy/CNTs‐based platforms exhibit excellent strain‐sensing performance manifested by a high gauge factor (GF = 2.64 × 104), wide sensing range (~270%), fast response/recovery time (~155/195 ms), excellent stability (~15,000 cycles at 40% strain), and sensitive ML characteristics under ultraviolet illumination. Benefiting from the novel fusion of digital data and visual images, important applications, including the detection of wrist pulses and human motions, and information dual‐encryption, are demonstrated. This study demonstrates the superiority of advanced structures and materials for realizing superior applications in wearable electronics.

Application of NiO deposited by atomic layer deposition for carbon nanotubes catalytic growth

Carbon nanotubes (CNTs) are a unique object for various kinds of electronic devices. At the same time, an important task remains the development of catalytic structure synthesis methods for repeatability and uniform growth of CNTs. One of such methods is atomic layer deposition (ALD). The article considers the effect of the initial NiO layer thickness obtained by the ALD method on the growth of carbon nanotubes array. Deposition of the CNTs was carried out by the direct current plasma-enhanced chemical vapor deposition method using a direct current discharge in an acetylene and ammonia at 680 °C. Before CNT deposition, the NiO film was reduced to metallic nickel in an ammonia atmosphere at 680 °C. Samples were studied by scanning and transmission electron microscopy. As a result, the thickness of the initial NiO film for intensive CNT growth was in the range of 3.5 to 3.9 nm. CNTs had a “multi-walled” structure and consisted of 15 ± 5 graphene layers. The density of the tubes was about 7.5 ± 0.2 × 1010 cm−2, and the length was 6–7.5 µm.

The Role of Carbon Nanotube Deposit in Catalytic Activity of FeOX-Based PECVD Thin Films Tested in RWGS Reaction

While the reverse water-gas shift (RWGS) reaction holds great promise as a method of converting CO2 to CO and subsequently into valuable fuels, achieving its commercial viability requires the development of highly efficient, selective, durable, and low-cost catalysts. Recently, thin-film nanocatalysts produced through plasma deposition (PECVD) have garnered significant attention in this domain. Among them, FeOx-based catalytic films deposited using Fe(CO)5 as a precursor, under reduced pressure (4–5 Pa) and a 13.56 MHz glow discharge, have demonstrated particular interest. Our study shows that by appropriately tuning the parameters of the plasma deposition process, it is feasible to generate nanocatalyst films exhibiting exceptional CO2 conversion (38% at 673 K) and CO selectivity (97%). Moreover, the study has revealed the formation of a carbon deposit containing carbon nanotubes (CNTs) during the RWGS reaction, significantly increasing the catalytic activity of the films. Through an analysis involving X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electron microscopy techniques (SEM and HRTEM), we have determined that CNTs not only serve as carriers for highly catalytically active Fe nanoparticles but also create nanoscale heterojunctions (p-n) with Fe2O3 nanoparticles, thereby enhancing their catalytic effect. This paper attempts to elucidate the differences and changes in the surface structure of FeOx-based films dictating the catalytic activity, which stems from both the conditions of plasma deposition and the environmental impact during the catalytic process.

Spray deposited carbon nanotube embedded ZnO as an electrons transport layer in inverted organic solar cells

In this report, the synthesis and characterization of ZnO and carbon nanotube (CNT) embedded ZnO composite thin films are presented. The obtained ZnO and CNT composite ZnO thin films are used as an electron transport layer (ETL) for bulk heterojunction (BHJ) inverted organic solar cell (IOSC) with the architecture of ITO/ZnO:CNT/PTB7:PC71BM/MoO3/Ag. Both ZnO and CNT composite ZnO thin films exhibited a highly preferred c-axis oriented (002) diffraction peak and the peak position is shifted toward a lower angle after embedding CNT into the ZnO matrix. The transmittance slightly decreases after CNT is embedded into the ZnO matrix. Completely wrapped CNT with the ZnO was confirmed by Scanning electron microscope (SEM) measurement. The resistivity of ZnO decreased from 2.02 × 10−2 to 5.61 × 10−3 Ω-cm and mobility increased from 4.30 to 15.24 cm2/V-s after adding CNT into the ZnO matrix. CNT composite ZnO thin film surface is found to be hydrophobic, providing good interfacial contact with the BHJ layer resulting to improve fill factor (FF) of IOSC. The performance of IOSC with CNT composite ZnO ETL layer was significantly improved with a power conversion efficiency of 6.76%, open circuit voltage (VOC) of 700 mV, short circuit current density (JSC) of 20.05 mA/cm2 and FF of 48.17%, respectively.

Methane Decomposition to Hydrogen Over Zirconia-Supported Fe Catalysts-Effects of the Modified Support.

Methane decomposition is a promising route to synthesize COx -free hydrogen and carbon nanomaterials (CNMs ). In this work, the impregnation method was employed for the preparation of the catalysts. Systematic investigations on the activity and stability of Fe-based catalysts were carried out in a packed-bed micro-activity reactor at 800 °C with a feed gas flow rate of 18 mL/min. The effect of doping Y2 O3 , MgO, SiO2 and TiO2 over ZrO2 on the catalytic performance was also studied. BET revealed that the specific surface areas and pore volumes are increased after SiO2 , TiO2 , and Y2 O3 are added to ZrO2 while MgO had a negative impact and hence a little decrease in specific surface area is observed. The catalytic activity results showed that the Fe-based catalyst supported over TiO2 -doped ZrO2 that is, Fe-TiZr, demonstrated the highest activity and stability, with a maximum methane conversion of 81.3 % during 180 min time-on-stream. At 800 °C, a maximum initial methane conversion of 73 %, 38 %, 64 %, and 69 % and a final carbon yield of 121 wt. %, 55 wt. %, 354 wt. %, and 174 wt. % was achieved using Fe-MgZr, Fe-SiZr, Fe-TiZr and Fe-YZr catalysts, respectively. Moreover, bulk deposition of uniform carbon nanotubes with a high degree of graphitization and different diameters was observed over the catalysts.

Electrochemical properties of CNT doped nanoporous tin oxide hybrid electrode formed on cold spray tin coating for supercapacitor application

In this study, a hybrid electrode was formed from a nanoporous tin oxide thin film and carbon nanotubes on a tin cold sprayed coating. Structural investigations were performed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Characterization results showed that using the pulsed electrophoretic method for the deposition of carbon nanotubes on nanoporous tin oxide leads to the formation of uniform distribution of carbon nanotube particles on the surface. The electrochemical characteristics of the resultant electrode were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The appropriate electrochemical performance of the hybrid electrode is attributed to high surface area and high conductivity due to the presence of carbon nanotubes. The presence of carbon nanotubes in the structure of porous tin oxide causes a significant increase in capacitance. The nanoporous tin oxide-CNT hybrid electrode had a specific capacitance of 0.036 F/cm2 at 50 mV·s−1, whiles the nanoporous tin oxide electrode had a capacitance of 0.011 F/cm2 at the same scan rate. Also, the adsorption and desorption reaction of the hybrid electrode is largely controlled by penetration. The results demonstrated that the nanoporous tin oxide-CNT hybrid electrode could be potentially used in energy storage applications.

Mechanisms for Chemical Vapor Deposition Carbon Nanotube Growth by Surface Modification of 316L Stainless Steel.

Mechanisms for Chemical Vapor Deposition Carbon Nanotube Growth by Surface Modification of 316L Stainless Steel.