Percolated pore networks of oxygen plasma-activated multi-walled carbon nanotubes for fast response, high sensitivity capacitive humidity sensors

H. P. Hong, K. H. Jung, J. H. Kim, K. H. Kwon, Cheol Jin Lee, K. N. Yun, N. K. Min

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We report on the preparation of capacitive-type relative humidity sensors incorporating plasma-activated multi-wall carbon nanotube (p-MWCNT) electrodes and on their performance compared with existing commercial technology. Highly open porous conductive electrodes, which are almost impossible to obtain with conventional metal electrodes, are fabricated by spray-depositing MWCNT networks on a polyimide layer. Oxygen plasma activation of the MWCNTs is also explored to improve the water adsorption of the MWCNT films, by introducing oxygen-containing functional groups on the CNT surface. Polyimide humidity sensors with optimized p-MWCNT network electrodes exhibit exceptionally fast response times (1.5 for adsorption and 2 s for desorption) and high sensitivity (0.75 pF/% RH). These results may be partially due to their percolated pore structure being more accessible for water molecules, expending the diffusion of moisture to the polyimide sensing film, and partially due to the oxygenated surface of p-MWCNT films, allocating more locations for adsorption or attraction of water molecules to contribute to the sensitivity.

Original languageEnglish
Article number085501
JournalNanotechnology
Volume24
Issue number8
DOIs
Publication statusPublished - 2013 Mar 1

Fingerprint

Capacitive sensors
Humidity sensors
Carbon Nanotubes
Humidity
Carbon nanotubes
Electrodes
Polyimides
Oxygen
Adsorption
Plasmas
Water
Molecules
Pore structure
Functional groups
Reaction Time
Desorption
Atmospheric humidity
Moisture
Metals
Chemical activation

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Science(all)

Cite this

Percolated pore networks of oxygen plasma-activated multi-walled carbon nanotubes for fast response, high sensitivity capacitive humidity sensors. / Hong, H. P.; Jung, K. H.; Kim, J. H.; Kwon, K. H.; Lee, Cheol Jin; Yun, K. N.; Min, N. K.

In: Nanotechnology, Vol. 24, No. 8, 085501, 01.03.2013.

Research output: Contribution to journalArticle

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