Engineers at the University of Maryland are challenging earlier theories about the behavior of nanoscale materials used to manufacture thermoelectric devices. Challenging the widespread assumption in nanotechnology that smaller is always better, engineers will develop future thermoelectric equipment.
Thermoelectric effect may be defined as the electric potential generated by a material when it responds to a change in temperature. On heating by an external source, these devices generate electricity. For instance, cars remodeled or manufactured with thermoelectric equipment positioned near the exhaust pipe can generate electricity from waste heat, thus improving their fuel efficiency. However, if the equipment is too large and inefficient, it will take up more energy than it saves.
Cornett and Professor Oded Rabin challenged some popular theories to solve this problem. Cornett stated that according to previously established models, the use of nanomaterials at minute dimensions would result in an increase in efficiency of power generation. He added that according to the models, the smaller the nanostructure, the enhancement would be more significant. It was evident that there was a problem with assumptions in the original models as it did not deliver the expected gains when thermoelectric equipment designed with nanoscale components were used.
Cornett and Rabin have put forth a new thermoelectric performance model that states that smaller is not better always. They used advanced computer modeling to examine the ability of thermoelectric nanowires with a thickness of only 100 to 1000 atoms, which is nearly 1000 times tinier that a human hair and showed that decreasing the radii of nanowires that measures 17nm or less does result in improved thermoelectric performance as predicted in previous models. However, an improvement in thermoelectric performance is also witnessed in nanowires that measure above 17 nm in radius as the radius increases.
Source: http://apl.aip.org/