Our comprehensive introduction to nanotechnology and nanoscience
with lots of information, examples and images
Nanomaterials and Nanoscience
Nanomaterials are not simply another step in the miniaturization of materials. They often require very different production approaches. There are several processes to create nanomaterials, classified as ‘top-down’ and ‘bottom-up’. Although many nanomaterials are currently at the laboratory stage of manufacture, a few of them are being commercialized.
Below we outline some examples of nanomaterials and the range of nanoscience that is aimed at understanding their properties. As will be seen, the behaviour of some nanomaterials is well understood, whereas others present greater challenges.
Nanoscale in One Dimension
Thin films, layers and surfaces
One-dimensional nanomaterials, such as thin films
and engineered surfaces, have been developed and
used for decades in fields such as electronic device
manufacture, chemistry and engineering. In the silicon
integrated-circuit industry, for example, many devices
rely on thin films for their operation, and control of film
thicknesses approaching the atomic level is routine.
Monolayers (layers that are one atom or molecule deep)
are also routinely made and used in chemistry. The
formation and properties of these layers are reasonably
well understood from the atomic level upwards, even in
quite complex layers (such as lubricants). Advances are
being made in the control of the composition and
smoothness of surfaces, and the growth of films.
Engineered surfaces with tailored properties such as
large surface area or specific reactivity are used routinely
in a range of applications such as in fuel cells and
catalysts. The large surface area
provided by nanoparticles, together with their ability to
self assemble on a support surface, could be of use in all
of these applications.
Although they represent incremental developments,
surfaces with enhanced properties should find applications
throughout the chemicals and energy sectors. The
benefits could surpass the obvious economic and
resource savings achieved by higher activity and greater
selectivity in reactors and separation processes, to
enabling small-scale distributed processing (making
chemicals as close as possible to the point of use). There
is already a move in the chemical industry towards this.
Another use could be the small-scale, on-site production
of high value chemicals such as pharmaceuticals.
Graphene and other single- and few-layer materials
Graphene is an atomic-scale honeycomb lattice made of carbon atoms. Graphene is undoubtedly emerging as one of the most promising nanomaterial because of its unique combination of superb properties, which opens a way for its exploitation in a wide spectrum of applications ranging from electronics to optics, sensors, and biodevices.
For instance, graphene-based nanomaterials have many promising applications in energy-related areas. Just some recent examples: Graphene improves both energy capacity and charge rate in rechargeable batteries; activated graphene makes superior supercapacitors for energy storage; graphene electrodes may lead to a promising approach for making solar cells that are inexpensive, lightweight and flexible; and multifunctional graphene mats are promising substrates for catalytic systems (read more:graphene nanotechnology in energy).
The fascination with atomic-layer materials that has started with graphene has spurred researchers to look for other 2D structures like for instance metal carbides and nitrides.
One particularly interesting analogue to graphene would be 2D silicon – silicene – because it could be synthesized and processed using mature semiconductor techniques, and more easily integrated into existing electronics than graphene is currently.
Another material of interest is 2D boron, an element with worlds of unexplored potential. And yet another new two-dimensional material – made up of layers of crystal known as molybdenum oxides – has unique properties that encourage the free flow of electrons at ultra-high speeds.