Computational modelling of an amide functionalized single-walled carbon nanotube based H2S gas sensor

Due to the importance of detection of hydrogen sulphide in some industries, we are seeking to design a real-time H2S gas sensor with high sensitivity and very low detection limit. Here, we have investigated the sensitivity of amido-functionalized semiconducting single-walled carbon nanotube (SWCNT), interconnected between two gold electrodes, in terms of electrical conductance behavior. For this reason, we have used the non-equilibrium Green's function method and density functional theory and compared our results to our previous study (SWCNT functionalized with palladium nanoclusters) to find the best H2S gas sensor with high sensitivity. Initially, the optimized structure of the SWCNT functionalized with amide groups with and without H2S gas is computed. Then, the electrical properties of the sensor prior to and after the exposure to H2S gas are computed and compared at different bias voltages. The highest sensitivity is found to be at 40 mV bias voltage with a current change of 1 order of magnitude in response to H2S gas which in comparison to SWCNT functionalized with palladium nanoclusters, the current change, and as a result the sensitivity, are more significant. So it is inferred that amido-functionalized SWCNT can act as an effective detector with a considerable current change.