Investigation of the H2O sensing mechanism of DC operated chemiresistors based on graphene oxide and thermally reduced graphene oxide

Sotirios Papamatthaiou, Dimitrios-P. Argyropoulos, Filippos Farmakis, Nikolaos Georgoulas

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Abstract

Graphene oxide (GO) is a promising material for H 2O vapour sensing. However, the H 2O sensing mechanisms are still under investigation especially in the case of thermally reduced GO. To this purpose, planar devices were fabricated by spin-coating graphene oxide on glass substrates. Ultra high response to H 2O was recorded but poor repeatability and stability over time were also noted. Three different degrees of thermal reduction were applied to improve material stability. An inverse change of resistance was observed for reduced graphene oxide compared to pure graphene oxide upon interaction with H 2O. The sensing mechanisms that govern GO and reduced GO behavior were studied based on DC measurements. In the case of GO, strong ionic conductivity was proposed whereas in the case of reduced GO mixed electronic/ionic with the leading mechanism affected by H 2O percentage in air, degree of material reduction, and sensor working temperature. Finally, it was found that by promoting one sensing mechanism over the other, improved operating humidity range of the sensor can be achieved.

Original languageEnglish
Article number8733871
Pages (from-to)7841-7848
Number of pages8
JournalIEEE Sensors Journal
Volume19
Issue number18
Early online date10 Jun 2019
DOIs
Publication statusPublished - 15 Sep 2019

Keywords

  • Reduced graphene oxide
  • activation energy
  • electronic conduction
  • ionic conduction
  • relative humidity sensor
  • thermal reduction

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering

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