An international team, in which physicists from the Autonoma University of Madrid (UAM) participate, has shown that thermoelectric refrigerators can be manufactured using organic molecules as an active element. The finding, published in Nature Nanotechnology, will allow the development of a new generation of efficient cooling devices at the service of nanoelectronics.
For about 20 years it has been suggested that molecular circuits – electrical circuits made with individual molecules that mimic the functions of diodes and transistors – could also behave like very efficient thermoelectric refrigerators. Now, an international team, made up of physicists from the Autonomous University of Madrid (UAM) and engineers from the University of Michigan (USA), has managed to prove it.
Guided by a quantum theory of transport and heat dissipation in nanocircuits, the researchers proved that it is possible to use organic molecules to control and increase the performance of thermoelectric cooling in electrical circuits.
Thermoelectric coolers are based on the physical phenomenon known as the Peltier effect, which consists of the conversion of electric current into heat. In this way they use electrical energy to cool a part of it at the expense of heating another. Compared to common refrigerators, such as those that we have at home, these refrigerators are environmentally friendly as they do not contain greenhouse substances or that affect the ozone layer.
Since molecular circuits are the ultimate limit of miniaturization, the new thermoelectric molecular refrigerator is the smallest possible cooler. Its manufacture and characterization required a new experimental platform, based on the combination of a microscope of atomic forces and a tiny ultra sensitive calorimeter.
These results, published in the journal Nature Nanotechnology, open the door to the design of a new generation of efficient cooling devices with wide applications in nanotechnology. Longji Cui, Ruijiao Miao, Kun Wang, Dakotah Thompson, Linda Angela Zotti, Juan Carlos Cuevas, Edgar Meyhofer, Pramod Reddy (2017). Peltier cooling in molecular junctions. Nature Nanotechnology, DOI: 10.1038/s41565-017-0020-z