Carbon nanotube assemblies enabled design of a hybrid thermo-electromagnetic sound transducer with unique sound generation features that are not available from conventional diaphragm and thermo-acoustic speakers. New work describes a hybrid thermo-electromagnetic sound transducer (TEMST) fabricated using highly porous multi-walled carbon nanotube sheet that was placed in the proximity of a permanent magnet. Upon electrical AC excitation, thermal response of the material is combined with diaphragm-like sheet oscillations induced by the electromagnetic action of the Lorentz force.
The space industry has a strong requirement to develop flexible electrostatic discharge protection layers for the exterior cover of satellites in order to protect the electronics of the spacecraft. A new study explores carbon nanotube-polyimide composite materials as a flexible alternative for the currently used indium tin oxide (ITO) coating, which is brittle and suffers from severe degradation of the electrical conductance due to fracture of the coating upon bending.
There has been a long debate in the nanotube community regarding the photocurrent generation mechanisms in individual nanotube devices. In early optoelectronic studies with single-walled carbon nanotubes, the interpretation of photocurrent was mostly based on photovoltaic mechanisms. In new work, researchers use the extra tunability of a double-gated device to conclusively demonstrate that strong photothermal effects are present in carbon nanotube devices.
Inspired by nature's ingenious biological designs, researchers have persistently attempted to mimic these biofunctionalities to bring technological breakthroughs. One of these morphologies - the unique shape of a helical coil - is not only interesting from a scientific standpoint but also pivotal, offering DNA its distinctive properties and propelling flagella in viscous fluids, to name a few. With the advent of personalized medicine on the horizon, researchers are now trying to use tiny springs made of carbon nanotubes, i.e. nanocoils, to propel nanorobots to perform microsurgeries.
Researchers have created a free-standing carbon nanotube paper electrode with high sulfur loading for lithium-sulfur batteries employing a bottom-up strategy to design and fabricate a hierarchical structure. This new fabrication method does not employ aluminum foil or binders, thereby fully utilizing the advantage of a Li-S system with high specific capacity. This proof-of-concept experiment indicates that the rational design of the nanostructured electrode offers the possibility to efficiently use the active materials at practical loading.
Researchers have demonstrated a unique coaxial carbon nanocable material with pristine carbon nanotubes as the core and nitrogen-doped wrinkled carbon layer as the shell. The active sites rendered by the surface enriched dopant atoms on the carbon nanocables are accessible and effective to catalyze the oxygen involved electrochemical reactions. These coaxial nanocables afford higher ORR/OER current compared with the routine bulk doped nitrogen-doped carbon nanotubes.
Researchers consider the rational combination of carbon nanotubes (CNTs) and graphene into three-dimensional hybrids an effective route to amplify the inherent physical properties at the macroscale. By in situ nitrogen doping and structural hybridization of carbon nanotubes and graphene, researchers have now successfully fabricated nitrogen-doped aligned carbon nanotube/graphene sandwiches. In this work, aligned CNTs and graphene layers were anchored to each other, constructing a sandwich-like hierarchical architecture with efficient 3D electron transfer pathways and ion diffusion channels.
The microstructures of carbon nanotube assemblies determine their properties, for example, highly graphitized CNTs exhibit excellent mechanical and electrical properties; while CNTs with defects and poor crystallinity are beneficial for research on field emission property and hydrogen storage capacity. Therefore, it is of vital importance to control the CNT microstructures effectively for desired applications. A new technique can solve a problem of three-dimensional orientation control of CNTs in microscopic scale.