Nanotechnology reports recently said that researchers at Empa might be able to solve the problem involving machines and electronic devices and develop a small electricity generator made of quantum dots that will work at room temperature.
Researcher Mickael Perrin, from Empa's Trasport at Nanoscale lab led by Michel Calame, came up with the notion of utilizing graphene nanoribbons, which are considered a specialty of Empa, a Phys.org report specified.
The first-ever graphene nanoribbons were synthesized by another Empa research group, Roman Fasel and his colleagues, at the Nanotech@Surfaces lab of Empa.
For many years already, the researchers at Empa have worked on various methods to develop electronic devices from such nanoribbons.
Suited for Low-Cost 'Internet-of-Things' Devices
Machines and electronic devices frequently produce waste heat that is hard to use. If electricity could be produced from this waste heat, it would provide a means for clean, not to mention, sustainable power production.
More so, such a technology would be perfectly suited for low-power electronics applications like wearables or low-cost "Internet-of-Things" devices.
This includes, for instance, wearable medical devices and sensors that have an array of applications in the healthcare and sports industry, mobility applications, as well as smart buildings.
Specifically, thermoelectric generators, machines that produce electricity by exploiting temperature differences, already exist although their conversion efficacy is typically low and only a small portion of electricity is produced.
Essentially, producing more electricity would require materials that at the same time, have high electrical conductivity and low thermal conductivity. Nonetheless, these two requirements are frequently mutually exclusive.
Solution Through Quantum Dots
In the past few years, a lot of research teams the world over have presented that thermoelectric conversion can be impressively enhanced by using quantum effects.
For instance, through the use of quantum dots, as detailed in a Nanowerk report, acting as highly selective energy filters, dramatic rises in conversion efficacy have been reported, some, even reaching some of the limits set by the so-called "laws of thermodynamics."
The problem is that quantum machines, also known as quantum heat engines, need to be cooled down to temperatures a few degrees above "absolute zero," and thus, something similar to this is hardly functional in daily life.
Graphene Nanoribbons Made to Behave Like Quantum Dots
Perrin was able to make graphene nanoribbons behave like quantum dots previously, with some of them stable up to a -123-degrees Celsius temperature, for example, at much higher temperatures compared to the quantum dots used previously for thermoelectric transformation.
Now, the objective in this study published in the ACS Nano journal is to incorporate such graphene nanoribbons into a quantum heat engine to make it useful at room temperature.
As the nanoribbons are just a few nanometers big, making contact with them will necessitate the development of special fabrication methods, which will be applied at the Binnig and Bohrer Nanotechnology Center in the IBM Research Center in Rüschlikon.
In addition to this, there will be a need for custom-designed measurement systems to characterize the efficiency of energy conversion.
If everything goes as planned, Perrin might be able to develop a small heat engine on a chip in the years yet to come. Not only could it produce electricity from waste heat, but conversely, by withdrawing the operation principle, it would be suitable for effective cooling.
Related information about graphene nanoribbons is shown on Bristol Composites Institute's YouTube video below:
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