This paper describes the thermoelectric properties 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, the Seebeck coefficient was examined as a function of metal nuclearity, oxidation state, and substituent on the organic ligand backbone. High Seebeck coefficients up to 73 μV/K and appreciable thermal stability with thermovoltage up to ∼3.3 mV at a heating temperature of 423 K were observed. An unusually high proximity of the highest occupied molecular orbital (HOMO) energy level to the Fermi level was revealed to give the remarkable thermoelectric performance as suggested by combined experiments and calculations. This work offers important insights into the development of molecular-scale devices for efficient thermoregulation and heat-to-electricity conversion.
Bibliographical noteFunding Information:
This research was supported by the NRF of Korea (NRF-2019R1A2C2011003, NRF-2019R1A6A1A11044070, NRF-2021M3F3A2A03017999, and NRF-2019K2A9A2A08000151). S.P. acknowledges the support of the POSCO TJ Park Doctoral Fellowship. The authors are grateful for the NMR facility in the Institute for Basic Science (IBS) Center for Molecular Spectroscopy and Dynamics. Y.T. acknowledge a research grant from JSPS KAKENHI (21K05211) and The Murata Science Foundation. The computations were performed by using the computer in the Research Center for Computational Science, Okazaki, Japan (21-IMS-C071, 22-IMS-C071).
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- metal alkynyl
- molecular junction
- Seebeck coefficient
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering