The importance of oxygen-containing defects on carbon nanotubes for the detection of polar and non-polar vapours through hydrogen bond formation

Watts, PCP, Mureau, N, Tang, Z, Miyajima, Y, Carey, JD and Silva, SRP (2007) The importance of oxygen-containing defects on carbon nanotubes for the detection of polar and non-polar vapours through hydrogen bond formation NANOTECHNOLOGY, 18 (17), ARTN 1.

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Abstract

We report the electrical responses of water vapour and O2 adsorption onto macroscopic multi-walled carbon nanotube (MWCNT) ropes, and compare the results with mats of acid-treated MWCNTs on SiO2 substrates in order to investigate the importance of oxygen-containing defects on CNTs. In the outgassed state both carbon nanotube (CNT) materials exhibit rapid changes in electrical resistance when exposed to dry air, humid air or water vapour at standard temperature and pressure (STP). The measured electrical responses are highly reversible at STP when cycled between humid air, vacuum and dry air. We report a decrease in resistance for the CNT materials in dry air, attributed to O2 p-type doping of the CNTs, whereas there is an increase in resistance when exposed to a humid environment. This latter effect is attributed to the formation of hydrogen bonding from the polar water molecules with the oxygen-containing defects on the CNTs. Our observations indicate that the increase in electrical resistance upon water absorption affects a reduction of the electron-withdrawing power of the oxygen-containing defect groups, thus leading to a reduced hole carrier concentration in the p-type nanotubes.

Item Type:	Article
Divisions :	Surrey research (other units)
Authors :	Watts, PCP, Mureau, N, Tang, Z, Miyajima, Y, Carey, JD and Silva, SRP
Date :	2 May 2007
DOI :	10.1088/0957-4484/18/17/175701
Uncontrolled Keywords :	Science & Technology, Technology, Physical Sciences, Nanoscience & Nanotechnology, Materials Science, Multidisciplinary, Physics, Applied, Science & Technology - Other Topics, Materials Science, Physics, ELECTRONIC-PROPERTIES, ELECTRICAL-TRANSPORT, COMPOSITE-MATERIAL, HUMIDITY SENSOR, GAS-ADSORPTION, FIELD-EMISSION, THIN-FILMS, SENSITIVITY, NO2, FUNCTIONALIZATION, carbon nanotube humidity sensors
Related URLs :	Author
Depositing User :	Symplectic Elements
Date Deposited :	28 Mar 2017 14:14
Last Modified :	24 Jan 2020 11:57
URI:	http://epubs.surrey.ac.uk/id/eprint/745443

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