Defect-Tolerant Aligned Dipoles within Two-Dimensional Plastic Lattices

ACS Nano. 2015 May 26;9(5):4734-42. doi: 10.1021/acsnano.5b01329. Epub 2015 Apr 17.

Abstract

Carboranethiol molecules self-assemble into upright molecular monolayers on Au{111} with aligned dipoles in two dimensions. The positions and offsets of each molecule's geometric apex and local dipole moment are measured and correlated with sub-Ångström precision. Juxtaposing simultaneously acquired images, we observe monodirectional offsets between the molecular apexes and dipole extrema. We determine dipole orientations using efficient new image analysis techniques and find aligned dipoles to be highly defect tolerant, crossing molecular domain boundaries and substrate step edges. The alignment observed, consistent with Monte Carlo simulations, forms through favorable intermolecular dipole-dipole interactions.

Keywords: carborane; defect tolerant; dipole alignment; ferroelectric; nanoscience; scanning tunneling microscopy; self-assembled monolayer; self-assembly; two-dimensional.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.