Influence of chemical treatment on the electrical conductivity and thermopower of expanded graphite foils

Mina Rastegaralam, Mingxing Piao, Gyutae Kim, Urszula Dettlaff-Weglikowska, Siegmar Roth

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We investigated the interaction of chemical materials with flexible graphite foils which were fabricated from the expanded graphite (EG) flakes by mechanical rolling and compressing. A variety of performed experiments demonstrated that the electrical conductivity and thermoelectric power (TEP) of the graphite foils can be modified by chemical treatments. In particular, the "as prepared" p-type graphite foil was successfully transferred into an n-type doped material upon a treatment with amine containing compounds. Generally, the acceptor-like chemicals increasing the concentration of the electric charge carriers enhanced the conductivity of the graphite foils, thereby, showing a decrease in the TEP reflected by the Seebeck coefficient, whereas the donor molecules significantly affected the conductivity and changed the sign and value of the TEP. Thermal and electrical insulating polymers, such as PVDF, PMMA, PVA, PS or PC, filling the inter-lamellar spacing reduced the conductivity of the foil due to increase of the layer-to-layer resistance. They also blocked heat flow in the foil, and consequently increased the Seebeck coefficient.

Original languageEnglish
Pages (from-to)1183-1187
Number of pages5
JournalPhysica Status Solidi (C) Current Topics in Solid State Physics
Volume10
Issue number7-8
DOIs
Publication statusPublished - 2013 Aug

Keywords

  • Chemical treatment
  • Electrical conductivity
  • Expanded graphite
  • Seebeck coefficient

ASJC Scopus subject areas

  • Condensed Matter Physics

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