Characterization of transparent conducting oxide surfaces using self-assembled electroactive monolayers

Jianfeng Li, Lian Wang, Jun Liu, Guennadi Evmenenko, Pulak Dutta, Tobin J. Marks

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The electronic properties of various transparent conducting oxide (TCO) surfaces are probed electrochemically via self-assembled monolayers (SAMs). A novel graftable probe molecule having a tethered trichlorosilyl group and a redox-active ferrocenyl functionality (Fc(CH2)4SiCl 3) is synthesized for this purpose. This molecule can be self-assembled via covalent bonds to form monolayers on various TCO surfaces. On as-received ITO, saturation coverage of 6.6 × 10-10 mol/cm2 by a close-packed monolayer and an electron-transfer rate of 6.65 s-1 is achieved after 9 h of chemisorption, as determined by cyclic voltammetry (CV) and synchrotron X-ray reflectivity. With this molecular probe, it is found that O2 plasma-treated ITO has a significantly greater electroactive coverage of 7.9 × 10-10 mol/cm 2 than as-received ITO. CV studies of this redox SAM on five different TCO surfaces reveal that MOCVD-derived CdO exhibits the greatest electroactive coverage (8.1 × 10-10 mol/cm2) and MOCVD-derived ZITO (ZnIn2.0Sn1.5O) exhibits the highest electron transfer rate (7.12 s-1).

Original languageEnglish
Pages (from-to)5755-5765
Number of pages11
JournalLangmuir
Volume24
Issue number11
DOIs
Publication statusPublished - Jun 3 2008

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ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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