Conversion of n-type CuTCNQ into p-type nitrogen-doped CuO and the implication for room temperature gas sensing

Shafiei, Mahnaz, Hoshyargar, Faegheh, Lipton-Duffin, Josh, Piloto, Carlo, Motta, Nunzio, & O'Mullane, Anthony P. (2015) Conversion of n-type CuTCNQ into p-type nitrogen-doped CuO and the implication for room temperature gas sensing. The Journal of Physical Chemistry Part C, 119(38), pp. 22208-22216.

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Abstract

Sensors to detect toxic and harmful gases are usually based on metal oxides that are operated at elevated temperature. However, enabling gas detection at room temperature (RT) is a significant ongoing challenge. Here, we address this issue by demonstrating that microrods of semiconducting CuTCNQ (TCNQ=7,7,8,8-tetracyanoquinodimethane) with nanostructured features can be employed as conductometric gas sensors operating at 50°C for detection of oxidizing and reducing gases such as NO2 and NH3. The sensor is evaluated at RT and up to 200°C. It was found that CuTCNQ is transformed into a N-doped CuO material with p-type conductivity when annealed at the maximum temperature. This is the first time that such a transformation, from a semiconducting charge transfer material into a N-doped metal oxide is detected. It is shown here that both the surface chemistry and the type of majority charge carrier within the sensing layer is critically important for the type of response towards oxidizing and reducing gases. A detailed physical description of NO2 and NH3 sensing mechanism at CuTCNQ and N-doped CuO is provided to explain the difference in the response. For the N-doped CuO sensor, a detection limit of 1 ppm for NO2 and 10 ppm for NH3 are achieved.

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ID Code: 87245
Item Type: Journal Article
Refereed: Yes
Additional URLs:
Keywords: sensors, CuTCNQ, nitrogen dioxide, ammonia, microstructured film, N doped CuO, X-ray photoelectron spectroscopy
DOI: 10.1021/acs.jpcc.5b06894
ISSN: 1932-7455
Subjects: Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > ORGANIC CHEMISTRY (030500)
Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > ORGANIC CHEMISTRY (030500) > Organic Chemical Synthesis (030503)
Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > NANOTECHNOLOGY (100700) > Nanomaterials (100708)
Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > OTHER TECHNOLOGY (109900) > Technology not elsewhere classified (109999)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Past > QUT Faculties & Divisions > Faculty of Science and Technology
Current > Institutes > Institute for Future Environments
Funding:
Copyright Owner: Copyright 2015 American Chemical Society
Deposited On: 04 Sep 2015 00:11
Last Modified: 11 Oct 2016 11:12

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