Over What Length Scale Does an Inorganic Substrate Perturb the Structure of a Glassy Organic Semiconductor?

Kushal Bagchi, Chuting Deng, Camille Bishop, Yuhui Li, Nicholas E. Jackson, Nicholas E. Jackson, Lian Yu, Lian Yu, M. F. Toney, J. J. De Pablo, J. J. De Pablo, M. D. Ediger

Research output: Contribution to journalArticlepeer-review

Abstract

While the bulk structure of vapor-deposited glasses has been extensively studied, structure at buried interfaces has received little attention, despite being important for organic electronic applications. To learn about glass structure at buried interfaces, we study the structure of vapor-deposited glasses of the organic semiconductor DSA-Ph (1,4-di-[4-(N,N-diphenyl)amino]styrylbenzene) as a function of film thickness; the structure is probed with grazing incidence X-ray scattering. We deposit on silicon and gold substrates and span a film thickness range of 10-600 nm. Our experiments demonstrate that interfacial molecular packing in vapor-deposited glasses of DSA-Ph is more disordered compared to the bulk. At a deposition temperature near room temperature, we estimate ∼8 nm near the substrate can have modified molecular packing. Molecular dynamics simulations of a coarse-grained representation of DSA-Ph reveal a similar length scale. In both the simulations and the experiments, deposition temperature controls glass structure beyond this interfacial layer of a few nanometers.

Original languageEnglish (US)
Pages (from-to)26717-26726
Number of pages10
JournalACS Applied Materials and Interfaces
Volume12
Issue number23
DOIs
StatePublished - Jun 10 2020
Externally publishedYes

Keywords

  • buried interface
  • coarse-grained simulations
  • GIWAXS
  • organic light-emitting diode
  • organic semiconductor
  • organic-inorganic interface
  • ultrathin films

ASJC Scopus subject areas

  • Materials Science(all)

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