Validating the Mott Formula with Self-Assembled Monolayer (SAM)-Based Large-Area Junctions: Effect of Length, Backbone, Spacer, Substituent, and Electrode on the Thermopower of SAMs

Sohyun Park, Jiung Jang, Hyo Jae Yoon

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Understanding how the Seebeck effect of organic thermoelectric devices is associated with the chemical structure of active molecules within the devices is a key goal in organic and molecular thermoelectrics. This paper describes a series of physical-organic studies that investigate structure-thermopower relationships in self-assembled monolayers (SAMs) through measurements of the Seebeck coefficient (S, μV/K) using the eutectic gallium-indium (EGaIn)-based junction technique. Several hypotheses were derived from a transmission function-based simple toy model, the Lorentzian transmission function-based Mott formula. These hypotheses were tested by comparing values ofSfor simple alkyl and aryl molecules with different structures in terms of backbone, length, spacer, anchor, and substituent, and for different electrodes (Au vs Ag), and by monitoring responses ofSto the structural modifications. Experimentally obtainedSvalues were further reconciled with values simulated by the Mott formula and with interfacial electronic structure and molecule-electrode coupling strength, independently measured by ultraviolet photoelectron spectroscopy and transition voltage spectroscopy.

Original languageEnglish
Pages (from-to)20035-20047
Number of pages13
JournalJournal of Physical Chemistry C
Volume125
Issue number36
DOIs
Publication statusPublished - 2021 Sep 16

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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