Electrical and dielectric properties of exfoliated graphite/polyimide composite films with low percolation threshold

Li Yu, Yi He Zhang, Jiwu Shang, Shan Ming Ke, Wang Shu Tong, Bo Shen, Haitao Huang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

11 Citations (Scopus)

Abstract

Exfoliated graphite/polyimide composite films were synthesized by in situ polymerization. The electrical and dielectric properties of composite films with different volume fraction of exfoliated graphite were investigated over the frequency range from 103Hz to 3 × 106Hz. The dielectric behavior of the composite films was investigated by percolation theory and a microcapacitor model. A low percolation threshold fc≈ 3.1 vol.% was obtained due to the high aspect ratio of the exfoliated graphite. Both the dielectric constant and alternating-current (AC) conductivity showed an abrupt increase in the vicinity of the percolation threshold. The ultralarge enhancement of the dielectric constant near and beyond the percolation threshold was due to Maxwell-Wagner-Sillars (MWS) interfacial polarization between the exfoliated graphite and polyimide and interface polarization between the composite film and electrode.
Original languageEnglish
Pages (from-to)2439-2446
Number of pages8
JournalJournal of Electronic Materials
Volume41
Issue number9
DOIs
Publication statusPublished - 1 Sep 2012

Keywords

  • Dielectrics
  • exfoliated graphite
  • polyimide
  • thin films

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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