Strategies for Controlling Through-Space Charge Transport in Metal-Organic Frameworks via Structural Modifications

Christian Winkler, Egbert Zojer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

In recent years, charge transport in metal-organic frameworks (MOFs) has shifted into the focus of scientific research. In this context, systems with efficient through-space charge transport pathways resulting from π-stacked conjugated linkers are of particular interest. In the current manuscript, we use density functional theory-based simulations to provide a detailed understanding of such MOFs, which, in the present case, are derived from the prototypical Zn2(TTFTB) system (with TTFTB4− corresponding to tetrathiafulvalene tetrabenzoate). In particular, we show that factors such as the relative arrangement of neighboring linkers and the details of the structural conformations of the individual building blocks have a profound impact on bandwidths and charge transfer. Considering the helical stacking of individual tetrathiafulvalene (TTF) molecules around a screw axis as the dominant symmetry element in Zn2(TTFTB)-derived materials, the focus, here, is primarily on the impact of the relative rotation of neighboring molecules. Not unexpectedly, changing the stacking distance in the helix also plays a distinct role, especially for structures which display large electronic couplings to start with. The presented results provide guidelines for achieving structures with improved electronic couplings. It is, however, also shown that structural defects (especially missing linkers) provide major obstacles to charge transport in the studied, essentially one-dimensional systems. This suggests that especially the sample quality is a decisive factor for ensuring efficient through-space charge transport in MOFs comprising stacked π-systems.
Original languageEnglish
Article number2372
Pages (from-to)1-21
Number of pages21
JournalNanomaterials
Volume10
Issue number12
DOIs
Publication statusPublished - 28 Nov 2020

Keywords

  • metal organic famework
  • charge transport
  • through-space
  • effectice mass
  • defects
  • Through-space pathways
  • Charge transport
  • Metal-organic frameworks

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)

Fields of Expertise

  • Advanced Materials Science

Cooperations

  • NAWI Graz

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