Gas sensing at the nanoscale: engineering SWCNT-ITO nano-heterojunctions for the selective detection of NH3 and NO2 target molecules

F Rigoni; G Drera; S Pagliara; E Perghem; C Pintossi; A Goldoni; L Sangaletti

doi:10.1088/1361-6528/28/3/035502

Gas sensing at the nanoscale: engineering SWCNT-ITO nano-heterojunctions for the selective detection of NH₃ and NO₂ target molecules

Nanotechnology. 2017 Jan 20;28(3):035502. doi: 10.1088/1361-6528/28/3/035502. Epub 2016 Dec 14.

Authors

F Rigoni¹, G Drera, S Pagliara, E Perghem, C Pintossi, A Goldoni, L Sangaletti

Affiliation

¹ Interdisciplinary Laboratory for Advanced Materials Physics and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, via dei Musei 41 I-25121 Brescia, Italy. Sensor Lab, Department of Information Engineering, University of Brescia & CNR-INO, Brescia-Italy.

PMID: 27966471
DOI: 10.1088/1361-6528/28/3/035502

Abstract

The gas response of single-wall carbon nanotubes (SWCNT) functionalized with indium tin oxide (ITO) nanoparticles (NP) has been studied at room temperature and an enhanced sensitivity to ammonia and nitrogen dioxide is demonstrated. The higher sensitivity in the functionalized sample is related to the creation of nano-heterojunctions at the interface between SWCNT bundles and ITO NP. Furthermore, the different response of the two devices upon NO₂ exposure provides a way to enhance also the selectivity. This behavior is rationalized by considering a gas sensing mechanism based on the build-up of space-charge layers at the junctions. Finally, full recovery of the signal after exposure to NO₂ is achieved by UV irradiation for the functionalized sample, where the ITO NP can play a role to hinder the poisoning effects on SWCNT due to NO₂ chemisorption.