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

Abstract

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).

Reconstruction of Soft Biological Tissues Using Laser Soldering Technology with Temperature Control and Biopolymer Nanocomposites

“…To analyze the quality and durability of the laser welds formed using these solders, their microstructure must be investigated, and for solders containing SWCNT, the structure at the nanoscale must be analyzed. It has previously been shown that laser irradiation of nanotubes leads to the binding of carbon nanotubes [ 44 ]. Moreover, a laser-induced SWCNT framework structure formation in an albumin- and chitosan-based biopolymer matrix is possible [ 45 ].…”

Temperature Detectable Surface Coating with Carbon Nanotube/Epoxy Composites

“…The observed increase in electrical conductivity of the CNT/EP coating is due to a well-dispersed CNT into the epoxy matrix as shown in Figure 3 c. The effectiveness of electron transfer between the CNTs is very highly dependent on these CNTs’ spacing distance. CNT/EP Coating does not reach the improved percolation network formation of multi-wall carbon nanotubes but exhibits excellent electrical conductivity [ 25 ].…”

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

“…After complete polymerization, the resulting nanocomposite was subjected to laser structuring [ 46 , 47 ]. It was treated with laser radiation to reduce the resistivity values, form welded joints between nanotubes, and form a structured MWCNT conductive network inside the nanocomposite [ 48 , 49 , 50 , 51 ].…”

“…Such methods are based on the mechanisms of action of concentrated energy, based on the latest advances in laser technology and precision mechanics. The use of the laser forming method proposed in this research makes it possible to further improve the electrical and mechanical characteristics [ 47 , 50 ]. The parameters of the laser irradiation were selected experimentally so as to prevent the combustion of the silicone.…”