Electrical detection of ppb region NO2 using Mg-porphyrin-modified graphene field-effect transistors
The trace detection of NO 2 through small sensors is essential for air quality measurement and the health field; however, small sensors based on electrical devices cannot detect NO 2 with the desired selectivity and quantitativity in the parts per billion (ppb) concentration region. In this study, w...
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Veröffentlicht in: | Nanoscale advances 2021-10, Vol.3 (20), p.5793-5800 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The trace detection of NO
2
through small sensors is essential for air quality measurement and the health field; however, small sensors based on electrical devices cannot detect NO
2
with the desired selectivity and quantitativity in the parts per billion (ppb) concentration region. In this study, we fabricated metalloporphyrin-modified graphene field-effect transistors (FETs). Mg-, Ni-, Cu-, and Co-porphyrins were deposited on the graphene FETs, and the transfer characteristics were measured. With the introduction of NO
2
in the ppb concentration region, the FETs of pristine graphene and Ni-, Cu-, and Co-porphyrin-modified graphene showed an insufficient response, whereas the Mg-porphyrin-modified graphene exhibited large voltage shifts in the transport characteristics. This indicates that Mg-porphyrin acts as an adsorption site for NO
2
molecules. An analysis of the Dirac-point voltage shifts with the introduction of NO
2
indicates that the shifts were well-fitted with the Langmuir adsorption isotherm model, and the limit of detection for NO
2
was found to be 0.3 ppb in N
2
. The relationship between the mobility and the Dirac-point voltage shift with the NO
2
concentration shows that the complex of NO
2
and Mg-porphyrin behaves as a point-like charge impurity. Moreover, the Mg-porphyrin-modified graphene FETs show less response to other gases (O
2
, H
2
, acetic acid, trimethylamine, methanol, and hexane), thus indicating high sensitivity for NO
2
detection. Furthermore, we successfully demonstrated the quantitative detection of NO
2
in air, which is near the environmental standards. In conclusion, the results of the Mg-porphyrin-modified graphene FETs enable a rapid, easy, and selective detectability.
The Mg-porphyrin-modified graphene FETs showed NO
2
detection at a low concentration of ppb order at room temperature and are highly selective toward NO
2
. |
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ISSN: | 2516-0230 |
DOI: | 10.1039/d1na00519g |