Ferroelectric Polarization and Second Harmonic Generation in Supramolecular Cocrystals with Two Axes of Charge-Transfer

J Am Chem Soc. 2017 Jul 12;139(27):9186-9191. doi: 10.1021/jacs.7b02279. Epub 2017 Jun 29.

Abstract

Ferroelectricity in organic materials remains a subject of great interest, given its potential impact as lightweight information storage media. Here we report supramolecular charge-transfer cocrystals formed by electron acceptor and donor molecules that exhibit ferroelectric behavior along two distinct crystallographic axes. The solid-state superstructure of the cocrystals reveals that a 2:1 ratio of acceptor to donor molecules assemble into nearly orthogonal mixed stacks in which the molecules are positioned for charge-transfer in face-to-face and edge-to-face orientations, held together by an extended hydrogen-bonding network. Polarization hysteresis was observed along the face-to-face and edge-to-face axes at room temperature. The noncentrosymmetric nature of the cocrystals, required to observe ferroelectric behavior, is demonstrated using second harmonic generation measurements. This finding suggests the possibility of designing supramolecular arrays in which organic molecules support multidimensional information storage.

Publication types

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

MeSH terms

  • Crystallization
  • Electricity
  • Hydrogen Bonding
  • Imidoesters / chemistry*
  • Imidoesters / isolation & purification
  • Macromolecular Substances / chemistry
  • Molecular Structure
  • Naphthols / chemistry*
  • Naphthols / isolation & purification
  • Particle Size

Substances

  • Imidoesters
  • Macromolecular Substances
  • Naphthols
  • pyromellitic diimide
  • 5-amino-1-naphthol