Modern electronics are based mainly on silicon, whose importance in the technological development of mankind can hardly be overestimated. However, to make a breakthrough step forward, new materials are needed, including those resistant to overheating of electronics,” says a physicist from Adam Mickiewicz University in an interview with PAP (Polish Press Agency).
DSc Bartłomiej Graczykowski, professor at the Adam Mickiewicz University in Poznań, added that these new nanomaterials are also an answer to the growing needs of the market with diminishing resources or even deficits, such as e.g., the crisis on the market of semiconductors – essential elements for building all kinds of electronics.
Nanostructures and nanomaterials are elements expressed in nanometres (nm) – one nanometre is one-billionth of a metre or one-millionth of a millimetre.
“Nanostructuring allows us to enhance or obtain completely new optical, electrical, thermal or mechanical properties of matter,” explained the scholarship holder of the Foundation for Polish Science.
“Nowadays, on the one hand, we have continuous miniaturization and increasing computational capabilities of electronics, but on the other hand, we are confronted with the growing problem of process heat, the so-called thermal crisis. It relies on the fact that constantly increasing power while decreasing volume leads to overheating of the electronics. What is more, most of the energy that humanity produces is ultimately converted into heat, and this is mainly the so-called waste heat,” Professor Graczykowski pointed out.
The solution to harness this lost energy could be to be able to convert this heat into electricity.
“Nanostructuring of semiconductor thin films or membranes allows us to reduce thermal conductivity while retaining or improving electrical conductivity. This makes it possible to use thermoelectric modules and self-powered sensors that convert environmental, process or waste heat directly into the electric current. The possibility of generating electricity from heat can be very significant, given that almost all devices (e.g., computers or mobile phones) generate process heat, and this is usually the aforementioned waste heat,” he said.
Materials that can convert electricity into a heat gradient (which is the case, for example, in tourist refrigerators) or vice versa – heat gradient into electricity – are called thermoelectric materials.
Their flexible counterparts – which react to changes in temperature – could be used, for example, to check whether food bought in a supermarket has been stored at the temperatures stated on the packaging.
“Such a thermoelectric material, even with a temporary temperature difference, will generate a current and, for example, change colour. It could be a form of sticker – a cheap thing, no extra power, and very useful,” the researcher assessed.
Currently, researchers looking for an alternative to silicon are pinning their hopes on nano-technology of van der Waals materials with a thickness of one or several molecular layers (several nanometers).
“Particularly promising is the study of transition metal dichalcogenides with a layer structure similar to that of the now-famous graphene. Importantly, unlike graphene, these materials are semiconductors and their physical properties depend strongly on their thickness, i.e., the number of molecular layers,” he said.
Recent research by Prof. Graczykowski’s team indicates that there are such materials that become softer as their thickness is reduced to a few molecular layers. Until now, it was thought that – based on the knowledge of graphene – the opposite was happening.
Referring to these results, Prof. Graczykowski pointed out that these thin semiconductors make it possible to move from the rigid architecture of silicon integrated circuits to flexible electronics giving freedom to deform the material. In the future, such a nanomaterial could be used e.g., in medicine to produce sensors that would look like a sticker and being stuck on the skin could e.g., monitor temperature or acidity levels.
In addition, the issue of producing high surface area nanomaterials is also mentioned among the challenges in finding successors for silicon used in electronics.
“It has to be a routine and controlled process and not based solely on a laboratory method,” the physicist explained.
“I think silicon will still reign for many years to come, but we must look to the future and already conduct fundamental research on new nanomaterials, many of which are promising,” concluded DSc Graczykowski.