Large Seebeck Values in Metal-Molecule-Semimetal Junctions Attained by a Gateless Level-Alignment Method

Tamar Frank, Shachar Shmueli, Mor Cohen Jungerman, Pini Shekhter, Yoram Selzer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Molecular junctions are potentially highly efficient devices for thermal energy harvesting since their transmission properties can be tailored to break electron-hole transport symmetry and consequently yield high Seebeck and Peltier coefficients. Full harnessing of this potential requires, however, a capability to precisely position their Fermi level within the transmission landscape. Currently, with the lack of such a “knob” for two-lead junctions, their thermoelectric performance is too low for applications. Here we report that the requested capability can be realized by using junctions with a semimetal lead and molecules with a tailored effect of their monolayers on the work function of the semimetal. The approach is demonstrated by junctions with monolayers of alkanethiols on bismuth (Bi). Fermi-level tuning enables in this case increasing the Seebeck coefficient by more than 2 orders of magnitude. The underlying mechanism of this capability is discussed, as well as its general applicability.

Original languageEnglish
Pages (from-to)10473-10479
Number of pages7
JournalNano Letters
Volume23
Issue number22
DOIs
StatePublished - 22 Nov 2023

Funding

FundersFunder number
Schmidt Futures foundation
Israel Science Foundation2203/23, 1059/18

    Keywords

    • Fermi-level tuning
    • Seebeck coefficient
    • molecular junctions
    • space-charge region
    • thermovoltage

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