How Ethylene Glycol Chains Enhance the Dielectric Constant of Organic Semiconductors: Molecular Origin and Frequency Dependence

Selim Sami*, Riccardo Alessandri, Ria Broer, Remco W. A. Havenith

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

22 Citations (Scopus)
147 Downloads (Pure)

Abstract

Incorporating ethylene glycols (EGs) into organic semiconductors has become the prominent strategy to increase their dielectric constant. However, EG's contribution to the dielectric constant is due to nuclear relaxations, and therefore, its relevance for various organic electronic applications depends on the time scale of these relaxations, which remains unknown. In this work, by means of a new computational protocol based on polarizable molecular dynamics simulations, the time- and frequency-dependent dielectric constant of a representative fullerene derivative with EG side chains is predicted, the origin of its unusually high dielectric constant is explained, and design suggestions are made to further increase it. Finally, a dielectric relaxation time of ∼1 ns is extracted which suggests that EGs may be too slow to reduce the Coulombic screening in organic photovoltaics but are definitely fast enough for organic thermoelectrics with much lower charge carrier velocities.

Original languageEnglish
Pages (from-to)17783-17789
Number of pages7
JournalACS Applied Materials & Interfaces
Volume12
Issue number15
DOIs
Publication statusPublished - 15-Apr-2020

Keywords

  • dielectric constant
  • ethylene glycol
  • molecular dynamics
  • organic photovoltaics
  • organic thermoelectrics
  • SIDE-CHAINS
  • DYNAMICS
  • PERMITTIVITY
  • SIMULATIONS
  • DERIVATIVES
  • RELAXATION
  • EFFICIENCY
  • STRATEGY
  • LIQUIDS
  • MODELS

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