High Seebeck Coefficient Achieved by Multinuclear Organometallic Molecular Junctions

This paper describes thermoelectric property of molecular junctions incorporating multinuclear ruthenium alkynyl complexes that comprise Ru(dppe)₂ (dppe = 1,2-bis(diphenylphosphino)ethane) fragments and diethylnyl aromatic bridging ligands with thioether anchors. Using the liquid metal technique, Seebeck coefficient was examined as a function of metal nuclearity, oxidation state, and substituent on the organic ligand backbone. High Seebeck coefficient up to 73 μV/K and appreciable thermal stability with thermovoltage up to ~3.3 mV at heating temperature of 423 K were observed. Unusually high proximity of highest occupied molecular orbital (HOMO) energy level to Fermi level was revealed to give the remarkable thermoelectric performance as suggested by combined experiment and calculation. This work offers important insights into the development of molecular-scale devices for efficient thermoregulation and heat-to-electricity conversion.

https://pubs.acs.org/doi/10.1021/acs.nanolett.2c03974