Human progress has long been denoted by the dominant material of the period. Will we soon be living in the Nanomaterial Age?
The kind of material used by a society has often served as a yardstick for how developed that society is. From the stone wheel to the iPhone, a bronze axe to a Boeing 747, materials technology has been our constant companion throughout the millennia, and a driving force for continued progress and societal change. Now it is believed that we may be on the cusp of another great materials revolution, this time powered by nanotechnology. With implications for fields ranging from clean energy to medicine, nanotechnology has the potential to have far-reaching impacts on many aspects of our lives, and may earn itself naming rights to the next age in the process.
Sticks and stones and metals
During the Stone Age, our ancestors used natural materials such as animal skins, plant fibres and, of course, stones. These materials were our bread and butter before bread or butter, until humans began to experiment with metalwork. Copper, alloyed with a bit of tin, had such superior properties to stone implements that if a society failed to use the new material, they found themselves in danger of being conquered. Thus, the Bronze Age was born. Bronze had its heyday for millennia, until bronze itself was surpassed by another stronger, more versatile metal. Further advancement in metalwork allowed the production of iron tools and weapons, followed by ones crafted from steel. These implements were stronger and sharper than their bronze counterparts, without a significant increase in weight. There is actually some contention among historians about what constitutes the end of the Iron Age. A common demarcation uses an increase in the survival of written histories, which reduced the burden previously placed on archaeology. However, some believe the Iron Age may have never really ended as iron and steel still play a substantial role in contemporary society.
While naming time periods after their defining material has fallen somewhat out of vogue, the progression of society is still driven by advances in materials science and technology.
The industrial revolution, globalisation and the information age
Coal and the steam engine literally and figuratively fuelled the industrial revolution, moulding us into our modern consumer culture. Before the industrial revolution, a high percentage of the population had to farm the land to provide enough food for everyone to survive. Mechanised farming practices reduced the burden on manpower, while also producing higher yields. As a result, few farmers were required to feed the growing urban populace. This freed up large sections of the population to pursue work in other fields, such as manufacturing, commerce and research. The importance of this transition is still evident today, including our tendency to group countries based on how industrialised they are.
Advances in lightweight materials, such as composites and light metals, facilitated the development of aircraft that fly us around an ever-shrinking globe, and allowed us to be propelled beyond our planet’s life-supporting atmosphere. In the final decades of the 20th century, the world got even smaller following the rapid development of silicon processing chips and personal electronics. The revolutionary impact these silicon products have had on modern society can’t be overstated. Indeed, this article was written, and is likely being read, on devices powered by what is effectively processed sand.
Much to the chagrin of silicon atoms everywhere, we are not currently in the silicon age, but the information or digital age. However, we are likely on the verge of another significant advance in materials technology.
The promises of the nanotechnology age
Scientists have been heralding the Nano Age, proclaiming “nanotechnology will become the most powerful tool the human species has ever used”. This is engineering on an atomic scale, the stuff of science fiction only decades ago. Now, some experts believe nanotechnology will prove to be the foundation of our wildest dreams (or darkest nightmares).
While such claims may seem sensational or outlandish, the inherent potential of nanotechnology is apparent in current research. The University of Queensland (UQ) boasts a nanomaterials research centre with a multidisciplinary team that is working to implement nanomaterials in three key research areas: energy, environment and health. If there can be consensus about issues that are integral to the survival of humanity, the shortlist must surely include these three.
Professor Lianzhou Wang is the director of the UQ Nanomaterials Centre, and his work is focused on the first two areas: energy and environment. Prof Wang’s group aims to use nanomaterials to improve the efficiency of solar cells. Due to Australia’s abundant sunshine, the country has a vested interest and solid track record in solar cell research. However, much of that research focuses on improving the efficiency of solar cells, and usually involves increasingly expensive materials and manufacturing techniques. Prof Wang has a more egalitarian approach and is focused on developing renewable energy technology that will be more accessible to the population at large. In his lab, nanomaterials such as metal oxides and quantum dots are used to create cheap, efficient solar cells with the hope of encouraging more widespread utilisation of this green power source.
Using nanotechnology, Prof Wang’s group can make solar cells that are cheaper than currently available commercial silicon and thin film solar cells. They are able to do this because nanomaterials have a much lower processing temperature than conventional materials, which corresponds to a decrease in manufacturing costs. Nanomaterials also impart flexibility during processing and design, as they can be printed on both flexible and rigid substrates.
“This is where nanomaterials can play a role: performance, of course, but also cost,” said Prof Wang. By reducing the cost of the solar cells, he hopes to lower the barrier to entry of the market and thereby introduce the technology to a greater proportion of the population. In the case of nanotechnology, it turns out that less really is more.
However, not content to call that a good day’s work, Prof Wang is also working toward a solution for another issue plaguing the green energy sector: power storage. Although not particularly nuanced, a common argument against green energies asks what happens when the sun isn’t shining or the wind isn’t blowing. As frustratingly reductive as this may seem, it still presents a serious challenge. The uptake of green energy sources, including solar, is severely limited by inadequate or expensive batteries. The inability to easily and effectively store unused power for a rainy day (pardon the pun) is a limiting factor for many renewable energy technologies.
In an effort to address this issue many research groups, including Prof Wang’s, intend to improve batteries with nanotechnology. As with solar cells, the advantage stems from their increased surface area. Nanoparticles, particularly nanocrystallites, have a higher surface area ratio than conventional battery materials, which allows shorter ion diffusion length and faster charge transfer. This not only increases the storage capacity of the battery, but also reduces charging time. Using this technique, Prof Wang’s group believe they have developed new cathode materials for lithium ion batteries that would potentially improve the mileage of electric cars from 450km/charge to 600-700km. “This is an increase of almost a third, and will make these cars competitive with most petrol-powered cars,” said Prof Wang.
Exploring how to harness nanomaterials for the betterment of the environment is another key research area for the UQ nanomaterials group. There are a variety of ways nanomaterials can assist in environmental management, but artificial photosynthesis is arguably one of the most innovative. Using nanoparticles as a photoactive catalyst, carbon dioxide in the atmosphere reacts with water to produce by-products including carbon monoxide, methane and hydrogen gas. Prof Wang sums up how remarkable this is: “We can not only remove the CO2 from the atmosphere, we [also] get something useful in the process.” All of the by-products mentioned (carbon monoxide, methane and hydrogen) are potential fuel or power sources. Consequently, artificial photosynthesis not only provides a useful tool for combating climate change, it also generates alternative fuel sources in the process.
Finally, nanotechnology may also prove useful for health applications in fields as diverse as targeted drug delivery, gene therapy, diagnostics and tissue engineering, demonstrating its broad potential in medicine. It is thought by some that nanotechnology may hold the key to curing cancer at the genetic level, while also providing insights about immortality.
Whether the next great age of humanity is officially labelled the Nano Age or not, nanotechnology will almost certainly play an instrumental role in future innovations and will shape societies for decades to come. Whether it be tackling cancer or climate change, it appears that anything is possible, if we just think small enough.
Edited by Ena Music