Vertical arrays of carbon nanotubes, called 'forests', are a common type of three-dimentional (3D) nanotube assembly that researchers work with in their labs. These forests can be produced by chemical vapor deposition technique and used for diverse applications such as in photo- or thermoacoustics, highly elastic conductive composites, for mechanical nanomanipulation, in catalysis, or as sensors in nanomedicine, just to name a few examples. These and other applications relay on connectivity of carbon nanotubes in the forest structure. New measurements show that room temperature electrical properties of this nanotube network reveal quite substantial nonlinerarities that became more pronounced at sample cooling.
Carbon nanotubes (CNTs) have not yet met commercial expectations from a decade ago, and now hot on its heels is graphene. Graphene is considered a hot candidate for applications such as computers, displays, photovoltaics, and flexible electronics. The biggest opportunity for both materials is in printed and potentially printed electronics. In a comparably short time a large amount of graphene materials have become commercially available contributing to further advancements and application development. At a fraction of the weight and cost of CNTs, graphene may displace carbon nanotubes and even indium tin oxide in some applications. Flexible, see-through displays may be the one application that finally puts graphene into the commercial spotlight.
Electronic devices with muscles-like stretchability have long been pursued, but not achieved due to the requirement that all materials in the devices - electrodes, semiconductor, and dielectric - are stretchable. In their pursuit of fully flexible and stretchable electronic devices, researchers have already reported stretchable solar cells and transistors as well as stretchable active-matrix displays. The nanomaterials used for these purposes range from coiled nanowires to graphene. Recently, researchers at UCLA have successfully demonstrated a stretchable polymer composite that is highly transparent and highly conductive, and applied this nanocomposite material to fabricating stretchable devices. This work represents a proof-of-concept, highly stretchable semiconductor device wherein every part of the device is intrinsically stretchable.
Super-tough materials with exceptional mechanical properties are in critical need for applications under extreme conditions such as jet engines, power turbines, catalytic heat exchangers, military armors, airplanes, and spacecraft. Researchers involved in improving man-made composite materials are trying to understand how some of the amazing high-performance materials found in nature can be copied or even improved upon. Nature has evolved complex bottom-up methods for fabricating ordered nanostructured materials that often have extraordinary mechanical strength and toughness. The main problem in making nanocomposite materials is how the separate components can be interfaced without losing the good properties of each component. Researchers were now able to show that biomolecules that may seem soft and fragile can actually strengthen a composite material by creating cohesion between two materials that differ much from each other.
Single-molecule magnets (SMM) are fascinating nanoscale structures with unique functional properties showing promise for high-density electronic data storage devices, solid state quantum computers, spintronic devices such as spin valves, and other advanced technological applications. Despite a flurry of research in this area - since an individual magnetic molecule represents the ultimate size limit to storing and processing information - the main challenge related to harnessing properties of SMM remained unsolved. A new study by a group of European researchers reports the successful encapsulation of single-molecule magnets in carbon nanotubes, yielding a new type of hybrid nanostructure that combines all the key single-molecule magnet properties of the guest molecules with the functional properties of the host CNT.
Integrating biological molecules or even complex molecular machines with man-made nanoelectronic devices is one of the ultimate goals of bionanotechnology. Already there is a growing community of researchers interested in this area of bio/nano integration where biological components are interfaced with inorganic nanomaterials to create new devices and systems that combine the desirable properties of each system. One particular nanomaterial used in this kind of research are carbon nanotubes (CNTs). Scientists now report the integration of a CNT transistor with olfactory receptor proteins. The ultimate goal of this type of research is to transfer the sensing properties of biological molecular systems to artificial electronic devices.
There is a growing body of research on using carbon nanotubes (CNTs) and other nanomaterials in neural engineering. Scientists are already exploring the feasibility of using CNTs to probe neural activity. With this research comes the need to develop a unified approach when assessing the toxicity of CNT in neurons. However, a complex picture emerges from the reported data: is it feasible to develop CNT-based devices as drug delivery vectors? Ultimately, are soluble CNT neurotoxic, and, if yes, to what degree? Given the often conflicting results of research reports on the biocompatibility of soluble CNT when administered to neurons in the central nervous system, a review article helps to clarify which aspects (technical or methodological) of these studies may be responsible for their heterogeneous conclusions.
Energy generation and storage is an important issue at the nanoscale. For tiny devices such as nano- and micro-electromechanical systems, autonomous power sources are crucial for practical applications. Progress is being made in designing and fabricating nanoscale power generators. But, as with the large, macroscale systems of future smart grids, there might be times when powered nanodevices need to bridge a slump in power generation/harvesting or they might be designed to run on stored energy altogether for a limited period of time. Researchers in China are now proposing that the high energy density and power density of carbon nanotubes makes them promising materials for the storage of mechanical energy. The team provides a structural model towards mechanical energy storage for nanodevices and also demonstrates a method to characterize and manipulate ultralong CNTs.