Superexchange Coupling-Induced Enhancements of Thermoelectric Performance in Saturated Molecules

Nayoung Cho, Seohyun Kang, Hyunju Lee, Hungu Kang, Gyu Don Kong, Hyo Jae Yoon

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

To develop thermoelectric devices, it is of the utmost importance to design organic building blocks to have efficient thermopower. Whereas conjugated and aromatic molecules with intrinsic narrow band gaps are attractive candidates to achieve efficient thermoelectric properties, saturated molecules are usually avoided owing to intrinsically poor thermopower. Here we demonstrate that thermopower of saturated molecules can be enhanced by superexchange coupling. Specifically, thermoelectric properties of large-area junctions that contain self-assembled monolayers of oligo(ethylene glycol) thiolates and alkanethiolates are compared. Through large-area thermopower measurements using a liquid metal top electrode, we show that the superexchange coupling enhances the Seebeck coefficient and counterintuitively leads to an increase in the Seebeck coefficient with increasing the length in a certain conformation. The improved thermoelectric performance is attributed to the superexchange-induced enhanced ability to mediate metal wave function in junctions. Our work offers new insights for improving the thermoelectric performance of nonconjugated, saturated molecules.

Original languageEnglish
Pages (from-to)360-366
Number of pages7
JournalNano Letters
Volume21
Issue number1
DOIs
Publication statusPublished - 2021 Jan 13

Keywords

  • EGaIn
  • molecular junction
  • saturated molecules
  • superexchange
  • thermopower

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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