Heat can be converted to electricity more efficiently using nanowires as thin as atoms, according to new research

• Atomically thin nanowires conduct less heat and more electricity at the same time, yielding unprecedented conversion efficiency in comparison to the same bulk material
• Research opens up future routes into renewable energy from heat-to-electricity conversion

Waste heat can be converted to electricity more efficiently using one-dimensional nanoscale materials as thin as an atom – ushering in a new way of generating sustainable energy – thanks to new research by the Universities of Warwick, Birmingham and Cambridge.

The researchers have found that the most effective thermoelectric materials can be realised by shaping them into the thinnest possible nanowires.

Thermoelectric materials harvest waste heat and convert it into electricity - and are much sought-after as a renewable and environmentally friendly source of energy.

The researchers were investigating the crystallisation of tin telluride in extremely narrow carbon nanotubes used as templates for the formation of these materials in their lowest dimensional form.

In a combined theoretical-experimental research, they were able not only to establish a direct dependence between the size of a template and a resulting structure of a nanowire, but also to demonstrate how this technique can be used for regulation of the thermoelectric efficiency of tin telluride formed into nanowires 1-2 atoms in diameter.

Dr Andrij Vasylenko, from the University of Warwick’s Department of Physics and the paper’s first author, commented: ‘In contrast to 3-dimensional material, isolated nanowires conduct less heat and more electricity at the same time. These unique properties yield unprecedented efficiency of heat-to-electricity conversion in one-dimensional materials.’

Co-investigator Dr Andrew Morris, from the University of Birmingham’s School of Metallurgy and Materials, said: ‘It's a great example of theory and experiment side-by-side. There is lots of excitement about nanoscale materials and by running quantum mechanical programs on supercomputers we have predicted the structures and properties of these sub-nanometer wires, so we're really moving into a new realm of 'picowires’.’

Dr Vasylenko continued: ‘This opens up an opportunity for creation of a new generation of thermoelectric generators, but also for exploration of alternative candidate materials for thermoelectrics among abundant and non-toxic chemical elements.’

With a growing demand for both miniatuarisation and enhanced efficiency of thermoelectrics, nanostructuring offers a viable route for targeting both objectives.

Their results are reported in the journal ACS Nano.

The research paper is entitled “Electronic Structure Control of Sub-nanometer 1D SnTe via Nanostructuring within Single-Walled Carbon Nanotubes” and is published in ACS Nano by Dr Andrij Vasylenko, Samuel Marks, Jamie M. Wynn, Paulo V. C. Medeiros, Quentin M. Ramasse, Andrew J. Morris, Jeremy Sloan and David Quigley.

The computational research was conducted on the ARCHER Supercomputer, funded by EPSRC, experimental imaging was performed in Warwick and also at STFC SuperSTEM also supported by the EPSRC.

For further information
Kate Chapple, Press Office, University of Birmingham, tel + 44 (0)121 414 2772 or + 44 (0)7789 921164.