To address global warming and net zero CO2 emission, the most important challenge of our time is to switch to cleaner energy sources. Converting heat energy into electricity could be a significant step towards this goal because more than 65% of the energy consumed globally is wasted in the form of heat through industrial processes and ICT devices. Thermoelectric (TE) materials can convert this waste heat to electricity provided materials with high TE efficiency can be identified. This is limited by the low efficiency, scarcity and toxicity of current TE materials. That is why there is a world-wide race to develop high efficiency TE materials with a projected global market of $1 billion by 2024.

Improvements in the performance of TE materials can be achieved through a better understanding and control of the electronic and vibrational structure of materials at the atomic and molecular levels and their scaling to large-area thin-film materials. Furthermore, there are opportunities to combine thermoelectricity with complementary routes toward green energy such as piezoelectricity, leading to hybrid molecular energy harvesting devices. To this end, this renewal FLF proposal aims to develop novel strategies and scientific understanding to design new molecular materials for hybrid energy harvesting through thermoelectric and piezoelectric effects. For this, both electron and phonon transport through such materials should be optimised. Since both electrons and phonons (vibrations) behave like waves, they can exhibit interference phenomena at a molecular scale at room temperature, which can be used to optimise their transport properties. This will be achieved in this proposal by controlling room-temperature quantum interference of electrons and room-temperature phonon interference, simultaneously to underpin new design strategies for efficient molecular thermo-piezo electricity.

This is a discovery science proposal and will elucidate design strategies for the development of new generation of thermo-piezo electric devices and consequently will change the community view on routes to engineer and realise highly efficient hybrid energy harvesting devices. It will contribute to the UK's mission to be a science superpower and will put the UK at the forefront of molecular thermo-piezoelectric research to provide timely solutions to a critical global challenge and capitalise on a growing global market.