Theoretical Approach to Evaluate the Gas-Sensing Performance of Graphene Nanoribbon/Oligothiophene Composites

Composite formation with graphene is an effective approach to increase the sensitivity of polythiophene (nPT) gas sensors. The interaction mechanism between gaseous analytes and graphene/nPT composite systems is still not clear, and density functional theory calculations are used to explore the inte...

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Bibliographic Details
Published in:ACS omega 2022-01, Vol.7 (2), p.2260-2274
Main Authors: Ashraf, Ayesha, Herbert, John M, Muhammad, Shabbir, Farooqi, Bilal Ahmad, Farooq, Umar, Salman, Muhammad, Ayub, Khurshid
Format: Article
Language:English
Subjects:
Composites
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Interaction energies
Layered materials
Mathematical methods
Two dimensional materials
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Summary:Composite formation with graphene is an effective approach to increase the sensitivity of polythiophene (nPT) gas sensors. The interaction mechanism between gaseous analytes and graphene/nPT composite systems is still not clear, and density functional theory calculations are used to explore the interaction mechanism between graphene/nPT nanoribbon composites (with n = 3–9 thiophene units) and gaseous analytes CO, NH3, SO2, and NO2. For the studied analytes, the interaction energy ranges from −44.28 kcal/mol for (C54H30-3PT)-NO2 to −2.37 kcal/mol for (C54H30-3PT)-CO at the counterpoise-corrected ωB97M-V/def2-TZVPD level of theory. The sensing mechanism is further evaluated by geometric analysis, ultraviolet–visible spectroscopy, density of-states analysis, calculation of global reactivity indices, and both frontier and natural bond orbital analyses. The variation in the highest occupied molecular orbital/lowest unoccupied molecular orbital gap of the composite indicates the change in conductivity upon complexation with the analyte. Energy decomposition analysis reveals that dispersion and charge transfer make the largest contributions to the interaction energy. The graphene/oligothiophene composite is more sensitive toward these analytes than either component taken alone due to larger changes in the orbital gap. The computational framework established in the present work can be used to evaluate and design graphene/nPT nanoribbon composite materials for gas sensors.
ISSN:2470-1343
2470-1343
DOI:10.1021/acsomega.1c05863