Structural changes and electrical properties of nanowelded multiwalled carbon nanotube junctions

Liu, Zhi; Yuan, Yanping; Shang, Yitong; Han, Weina

doi:10.1364/ao.57.007435

Cited by 9 publications

(8 citation statements)

References 27 publications

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“…Such structural disturbances, most likely, are not associated with formation of vacancy defects, but are more similar to the appearance of condensation products—nanosized inclusions on the surface of nanotubes. Thus, appearance of such nanoinclusions can be associated with sublimation of defective nanotubes with subsequent condensation of amorphous carbon on nanotubes that have not been irradiated by laser [ 77 , 79 ].…”

Section: Resultsmentioning

confidence: 99%

“…The versatility lies in the ability to change the surface parameters of CNT films by setting the amount of energy per unit area by controlling the radiation energy density, frequency and number of pulses. In series of works, the effect of laser welding of MWCNTs was demonstrated using irradiation without the use of auxiliary substances, which are called solders [ 77 , 78 , 79 , 80 ]. A continuous wave Yb laser (λ = 1064 nm) and pulsed Nd:YAG laser (λ = 355 nm) were used to create connections between MWCNTs.…”

Section: Introductionmentioning

confidence: 99%

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Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

et al. 2021

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A technology for the formation of electrically conductive nanostructures from single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and their hybrids with reduced graphene oxide (rGO) on Si substrate has been developed. Under the action of single pulses of laser irradiation, nanowelding of SWCNT and MWCNT nanotubes with graphene sheets was obtained. Dependences of electromagnetic wave absorption by films of short and long nanotubes with subnanometer and nanometer diameters on wavelength are calculated. It was determined from dependences that absorption maxima of various types of nanotubes are in the wavelength region of about 266 nm. It was found that contact between nanotube and graphene was formed in time up to 400 fs. Formation of networks of SWCNT/MWCNT and their hybrids with rGO at threshold energy densities of 0.3/0.5 J/cm2 is shown. With an increase in energy density above the threshold value, formation of amorphous carbon nanoinclusions on the surface of nanotubes was demonstrated. For all films, except the MWCNT film, an increase in defectiveness after laser irradiation was obtained, which is associated with appearance of C–C bonds with neighboring nanotubes or graphene sheets. CNTs played the role of bridges connecting graphene sheets. Laser-synthesized hybrid nanostructures demonstrated the highest hardness compared to pure nanotubes. Maximum hardness (52.7 GPa) was obtained for MWCNT/rGO topology. Regularity of an increase in electrical conductivity of nanostructures after laser irradiation has been established for films made of all nanomaterials. Hybrid structures of nanotubes and graphene sheets have the highest electrical conductivity compared to networks of pure nanotubes. Maximum electrical conductivity was obtained for MWCNT/rGO hybrid structure (~22.6 kS/m). Networks of nanotubes and CNT/rGO hybrids can be used to form strong electrically conductive interconnections in nanoelectronics, as well as to create components for flexible electronics and bioelectronics, including intelligent wearable devices (IWDs).

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

et al. 2021

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“…It is important to ensure the formation of contacts between nanotubes. The most crystalline contacts are formed when covalent C–C bonds appear [ 52 ]. During the formation of reliable contacts between nanotubes, the contact resistance decreases and, as a consequence, the electrical conductivity of the structures increases [ 53 ].…”

Section: Methodsmentioning

confidence: 99%

Flexible Strain-Sensitive Silicone-CNT Sensor for Human Motion Detection

et al. 2022

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This article describes the manufacturing technology of biocompatible flexible strain-sensitive sensor based on Ecoflex silicone and multi-walled carbon nanotubes (MWCNT). The sensor demonstrates resistive behavior. Structural, electrical, and mechanical characteristics are compared. It is shown that laser radiation significantly reduces the resistance of the material. Through laser radiation, electrically conductive networks of MWCNT are formed in a silicone matrix. The developed sensor demonstrates highly sensitive characteristics: gauge factor at 100% elongation −4.9, gauge factor at 90° bending −0.9%/deg, stretchability up to 725%, tensile strength 0.7 MPa, modulus of elasticity at 100% 46 kPa, and the temperature coefficient of resistance in the range of 30–40 °С is −2 × 10−3. There is a linear sensor response (with 1 ms response time) with a low hysteresis of ≤3%. An electronic unit for reading and processing sensor signals based on the ATXMEGA8E5-AU microcontroller has been developed. The unit was set to operate the sensor in the range of electrical resistance 5–150 kOhm. The Bluetooth module made it possible to transfer the received data to a personal computer. Currently, in the field of wearable technologies and health monitoring, a vital need is the development of flexible sensors attached to the human body to track various indicators. By integrating the sensor with the joints of the human hand, effective movement sensing has been demonstrated.

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“…To create branched junctions of CNTs, one can use various methods and approaches, including direct growth [11,12,13], high-energy electron beam irradiation [14,15,16], forming junctions in strong electrical, optical, and thermal fields [17,18,19], as well as using atomic force microscopy [20]. The laser nanowelding technique seems to be the most promising method for obtaining high-quality 3D scaffolds from CNT junctions [21]. It was found that the key factors in nanowelding of MWCNTs are the degree of graphitization of MWCNTs, the irradiation time, the type of substrate, and others [21,22,23,24].…”

Section: Introductionmentioning

confidence: 99%

“…The laser nanowelding technique seems to be the most promising method for obtaining high-quality 3D scaffolds from CNT junctions [21]. It was found that the key factors in nanowelding of MWCNTs are the degree of graphitization of MWCNTs, the irradiation time, the type of substrate, and others [21,22,23,24]. However, the degree of absorption of laser radiation by CNTs during welding at various wavelengths was not previously estimated.…”

Section: Introductionmentioning

confidence: 99%

Protein-Polymer Matrices with Embedded Carbon Nanotubes for Tissue Engineering: Regularities of Formation and Features of Interaction with Cell Membranes

et al. 2019

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This paper reveals the mechanism of nanowelding a branched network of single-walled carbon nanotubes (SWCNTs) used as a framework for the formation of protein–polymer matrices with albumin, collagen, and chitosan. It is shown that the introduction of certain point defects into the structure of SWCNTs (single vacancy, double vacancy, Stone–Wales defect, and a mixed defect) allows us to obtain strong heating in defective regions as compared to ideal SWCNTs. The wavelengths at which absorption reaches 50% are determined. Non-uniform absorption of laser radiation along with inefficient heat removal in defective regions determines the formation of hot spots, in which nanowelding of SWCNTs is observed even at 0.36 nm between contacting surfaces. The regularities of formation of layered protein–polymer matrices and the features of their interaction with cell membrane are revealed. All studies are carried out in silico using high-precision quantum approaches.

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Structural changes and electrical properties of nanowelded multiwalled carbon nanotube junctions

Cited by 9 publications

References 27 publications

Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

Flexible Strain-Sensitive Silicone-CNT Sensor for Human Motion Detection

Protein-Polymer Matrices with Embedded Carbon Nanotubes for Tissue Engineering: Regularities of Formation and Features of Interaction with Cell Membranes

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