A few days ago, we had harped about the potentially high solar efficiency of perovskite nanowires. Well, this time around, researchers at Sandia National Labs have dabbled with the procedure of controlling nanowire sizes and uniformity – and these regulated crystal states could be used in various thermoelectric applications. Now from the physical perspective, the very scope of thermoelectric materials entails the generation of electric current due to the magnitude of temperature difference in the variant parts of the substance. To that end, the scientists believe that these new nanowires can be potentially used by automakers to harvest energy from the heat dissipated by the car exhaust systems.
In conventional terms, experts have not been able to use the regular materials for commercial thermoelectric applications due to their thermoelectric efficiency (the ratio of high electric conductivity and low thermal conductivity). As a result, the Sandia researchers have opted for nanowires whose crystals structures can be controlled and manufactured in a uniform manner, thus pertaining to effective thermoelectric material. For this, the scientists utilized a procedure known as electroforming in which the material is delivered at a consistent rate (at room temperature), which in turn allows the nanowires to grow equably in size and orientation. The resultant one-directional assimilation of the nanocrystals along with their uniform composition, makes it conducive to the flow of electrons through the tiny conductors.
However, in spite of such advantages, the researchers still have to establish the crucial electrical contact with the regulated nanowires. This can prove to be problematic since thermoelectric materials have a tendency to form oxides or intermetallics that have higher electric contact resistance. To that end, the nanowire-material from the electroforming procedure has shown some contact efficiency at the bottom section of the unidirectional array, but has still to prove its worth at the top part. This predicament is expected to be solved on additional tinkering of the process (which would require additional funding) – after which the scientists can measure and analyze the thermoelectric properties of the aforementioned nanomaterial arrays.
Lower Image Credit: Randy Montoya