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[16a-B508-1] Thermoelectric Measurements of Self-Assembled Monolayer of Multinuclear Ruthenium Alkynyl Complexes
Keywords:Self-assembled monolayer, Seebeck coefficient, Ruthenium alkynyl complex
Molecules with high Seebeck coefficients (S) have potential applications in thermoelectric materials. However, their S values at single-molecule and self-assembled monolayer levels are low partly due to large energy gaps (E–EF) between molecular frontier orbital energy and Fermi energy of the electrodes. We have recently reported highly conducting organometallic molecules with electron-rich ruthenium tetraphosphine fragments in molecular junction. The theoretical study suggests that their small energy gaps (E–EF), which may lead to a large Seebeck coefficient. In this study, we report the Seebeck coefficient of multinuclear ruthenium complexes bridged by p-diethynylbenzene-diyl linkers and examine their thermoelectric properties.
Thermoelectric measurements for mono-, di- and tri-ruthenium complexes were conducted using the Au-molecule-EGaIn/Ga2O3 system. Upon heating the gold electrode, the S values increased with the number of metal fragments, and the trinuclear complex showed a value exceeding 70 µV/K, which is the highest S value obtained by SAM junction reported so far. Theoretical calculations and cyclic voltammograms indicate that the high Seebeck coefficient is caused by the high-lying HOMO, which destabilizes as the number of metal fragments increases.
Thermoelectric measurements for mono-, di- and tri-ruthenium complexes were conducted using the Au-molecule-EGaIn/Ga2O3 system. Upon heating the gold electrode, the S values increased with the number of metal fragments, and the trinuclear complex showed a value exceeding 70 µV/K, which is the highest S value obtained by SAM junction reported so far. Theoretical calculations and cyclic voltammograms indicate that the high Seebeck coefficient is caused by the high-lying HOMO, which destabilizes as the number of metal fragments increases.