The field of nanotechnology has been around for some time. It has taken many forms over the years, from techniques that introduce nanoscale features into bulk materials (e.g., lithography) to making highly functional materials from scratch that are 100nm or less and, in some cases, just a single atomic layer in thickness. The field of nanotechnology is far-reaching. Because it encompasses aspects of every traditional scientific field (biology, chemistry, physics, and engineering), the application landscape of nanotechnology and nanomaterials is vast and continues to grow.
While nanotechnology has existed for a long while, many niche areas are still emerging. Some of these are still in a relative state of infancy compared to other areas. However, even in areas with low technology readiness levels, quite a bit of research is going into seeing how nanotechnology can be applied to different applications and industrial/market sectors. One area that is relatively new compared to more established areas of nanotechnology and has yet to gather as much attention in the wider community is the field of nanoarchitectonics.
What Is Nanoarchitectonics?
Nanoarchitectonics is a field of nanotechnology involved with manipulating and customizing materials to fit a desired application or system. Though atomic and molecular manipulation methods have been used in many fields, and the concepts involved within nanoarchitectonics have been around for many years in the nanotechnology and adjacent scientific fields, it is only recently that it became its own defined field with set principles that underpin if someone is using nanoarchitectonic techniques.
Nanoarchitectonics is essentially a methodology bridge that spans both the synthesis methods used for creating nanomaterials with the atomic manipulation techniques used to change and customize existing materials. Nanoarchitectonics arranges atoms and molecules into a desired configuration based on the needs of the application and is a way of creating materials that do not occur naturally, i.e., they are wholly man-made materials. Nanoarchitectonics also uses different fabrication and atomic manipulation methods to fully understand the functions of materials so that scientists can better understand how to manipulate the material in the most optimal way.
Nanoarchitectonics is an interdisciplinary area that brings together various aspects of wet chemical synthesis (inorganic, organic, and supramolecular chemistry) with materials science and fabrication engineering to create materials better suited to their application than if they were produced by normal synthetic routes alone.
Because nanoarchitectonics is a combination of material creation and material manipulation, many methods are used in the field. Developers can create materials through a number of techniques, such as self-assembly, but it’s the atomic manipulation side of things that brings together the field of nanoarchitectonics. Otherwise, the materials created would be produced through standard synthetic methods.
Developers employ a range of techniques to manipulate the atoms during synthesis or post-fabrication, including external fields (magnetic, electric etc.), probe microscopy techniques (such as scanning tunneling microscopy or atomic force microscopy), self-assembly growth within a material, and chemical manipulation.
The result of the whole process is typically a material that has been altered in some way (similar to how doping with adatoms affects semiconductor properties). The material structures that are created by combining these different processes into an engineering fabrication strategy tend to be much more hierarchical than those produced by other means, and this combination of manufacturing approaches means that more complex structures can be obtained than by other means. When it comes to advanced materials, the features at the atomic and molecular level tend to be responsible for the functional and active aspects of a material—especially in electronic devices—so being able to create specific active features by understanding the fabrication process in more detail could open new materials for advanced technologies.
As it stands, the majority of materials and systems that have been utilizing nanoarchitectonic principles have been in medical and biological applications because many systems in nature are already produced by self-assembly, and it is much easier to manipulate the atomic structure of many organic and biological materials than it is inorganic materials—and it is typically more inorganic materials (nano or otherwise) that are found in high-tech applications such as energy storage, computing, or sensors (there are of course exceptions). For example, silicon, ITO, lithium electrodes, piezoelectric materials, GaAs semiconductors are all inorganic materials and commonly found materials in advanced technologies. So, there is a lot of research in the biological fields, but interest is starting to grow in more advanced technology fields as well.
Looking Towards More High-Tech Devices
There has been a lot of use of nanoarchitectonics in biological and medicinal applications. While high-tech applications are still relatively unheard of in comparison, there are some examples where nanoarchitectonic principles are being applied to electronic devices.
One of the most significant areas of interest in using nanoarchitectonic methods is in the creation of more efficient energy storage devices, in particular supercapacitor technologies. Supercapacitors rely on having a high active surface area to store charge, and nanoarchitectonics analyses and manipulation methods are helping to strategically design porous carbon materials with controlled pore sizes and size distribution. This is to help improve the power performance of supercapacitors so that they can store and release more charge, as these optimization approaches can also help to create a more efficient surface in terms of textural properties (roughness, smoothness, etc.) to fine-tune the electronic properties of advanced supercapacitors.
Another area where nanoarchitectonics has been useful is in the development of more functional nanowires. Nanowire technology is still in a stage of commercial infancy but has been touted for a number of small-scale and flexible devices in the future. Using nanoarchitectonics over standard fabrication routes enables scientists and engineers to measure the electrical conduction in one-dimensional materials to determine if they are suitable for nanowire development. This approach could enable more efficient nanowires to be developed in the future by finding the ideal base material for a device and altering its properties to fit the application. So nanoarchitectonics could become a key way for enabling the realization of nanoscale circuits on a wider scale than is possible today.
Finally, there are a number of semiconductors out there which show some beneficial properties, but the bandgap could be better suited to a specific device. There are also wholly conductive materials, such as graphene, that have much potential in certain applications, but the lack of a bandgap makes them unsuitable. While doping is a common approach, different semiconductor materials can now be made using nanoarchitectonic principles through bandgap engineering methods.
By engineering the bandgap of materials through nanoarchitectonic methods—typically by creating periodic nanostructures in the material—developers can control the material’s electronic properties to a much greater degree. Aside from the direct impact on the semiconductor materials, these approaches can also better engineer more efficient heterojunctions between semiconductor materials and nanomaterial layers. And in the case of the latter, interest exists in creating smaller interfaces for miniaturized electronics, so the ability to optimize more effectively using nanomaterials could be a way of creating more advanced devices for future technologies.
Nanoarchitectonics is a technological process combining material fabrication and atomic manipulation methods to create functional and active nanoscale features in materials so that their properties and features can be much better tailored to an application than fabrication methods alone. Nanoarchitectonics arranges atoms and molecules into a desired configuration based on the needs of the application and is a way of creating materials that do not occur naturally, i.e., they are wholly man-made materials. The ability to analyze, create, and manipulate atoms to make completely new materials suited to their application could help realize much more efficient and smaller electronic systems in the future across a range of technology areas. The tools are already being used in many high-tech areas, but this multi-faceted approach could be the key to unlocking a greater use of nanostructured materials in more high-tech devices.