Revealing the Local Electronic Structure of a Single-Layer Covalent Organic Framework through Electronic Decoupling

Daniel J. Rizzo, Qingqing Dai, Christopher Bronner, Gregory Veber, Brian J. Smith, Michio Matsumoto, Simil Thomas, Giang D. Nguyen, Patrick R. Forrester, William Zhao, Jakob H. Jørgensen, William R. Dichtel, Felix R. Fischer, Hong Li, Jean Luc Bredas, Michael F. Crommie

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Covalent organic frameworks (COFs) are molecule-based 2D and 3D materials that possess a wide range of mechanical and electronic properties. We have performed a joint experimental and theoretical study of the electronic structure of boroxine-linked COFs grown under ultrahigh vacuum conditions and characterized using scanning tunneling spectroscopy on Au(111) and hBN/Cu(111) substrates. Our results show that a single hBN layer electronically decouples the COF from the metallic substrate, thus suppressing substrate-induced broadening and revealing new features in the COF electronic local density of states (LDOS). The resulting sharpening of LDOS features allows us to experimentally determine the COF band gap, bandwidths, and the electronic hopping amplitude between adjacent COF bridge sites. These experimental parameters are consistent with the results of first-principles theoretical predictions.

Original languageEnglish (US)
Pages (from-to)963-970
Number of pages8
JournalNano letters
Volume20
Issue number2
DOIs
StatePublished - Feb 12 2020

Keywords

  • 2D polymer
  • Covalent organic frameworks (COFs)
  • Kagome lattice
  • biphenyl COF (BP-COF)
  • density functional theory (DFT)
  • scanning tunneling microscopy (STM)
  • scanning tunneling spectroscopy (STS)

ASJC Scopus subject areas

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

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