Thermoelectricity can offer a sustainable path to recover and convert waste heat into readily available electric energy [1]. With the ubiquity of electronic devices and wearables, the recovery of even small amounts of heat becomes relevant to extend the operational time of low power devices. Here, we are interested in developing and studying room temperature thermoelectric materials obtained by assembling ligand-terminated nanoparticles into macroscopic solids and/or films.

The materials architecture consists in an extended, non-necessarily ordered, 3D network of electrically conducting molecular junctions bridging nanometer-size quantum dots. This design should provide enhanced thermoelectric properties by charge carrier energy filtering at the inter-particle level, and by blocking phonons at the quantum dot – ligand interface due to vibrations mismatch.

We measure the Seebeck coefficient and the electrical conductivity in FET configuration, with an innovative methodology based on a phase-sensitive demodulation technique.

SEM image of a representative thermoelectric device with a channel length of 8 μm.

Collaborators: Jacopo Oswald, Gökhan Kara, Michael Stiefel, Dr. Ivan Shorubalko, Prof. Michel Calame

Partners: Prof. Liberato Manna et al., IIT (Quantum dots), IIT), and Prof. Maksym Kovalenko et al., Empa & ETHZ (Quantum dots).

Funding: This project is partially funded by The EMPAPOSTDOCS-II programme. The EMPAPOSTDOCS-II programme has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement number 754364.

1. Beretta, D., Neophytou, N., Hodges, J.M., Kanatzidis, M.G., Narducci, D., Martin-Gonzalez, M., Beekman, M., Balke, B., Cerretti, G., Tremel, W. and Zevalkink, A., 2019. Thermoelectrics: From history, a window to the fu-ture. Materials Science and Engineering: R: Reports, 138, p.100501.