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 (PT) gas sensors. The interaction mechanism between gaseous analytes and graphene/PT composite systems is still not clear, and density functional theory calculations are used to explore the interaction mechanism between graphene/PT nanoribbon composites (with = 3-9 thiophene units) and gaseous analytes CO, NH, SO, and NO. For the studied analytes, the interaction energy ranges from -44.

Polyaniline emeraldine salt as selective electrochemical sensor for HBr over HCl: a systematic density functional theory study through oligomer approach.

Density functional theory (DFT) calculations are performed to rationalize the experimentally observed sensitivity and selectivity of polyaniline emeraldine for hydrogen bromide over hydrogen chloride. The interaction behaviour is studied at UB3LYP method of density functional theory through oligomer approach. The properties for polymers are obtained extrapolation through second-degree polynomial fit.

Remarkable enhancement in sensor ability of polyaniline upon composite formation with ZnO for industrial effluents.

Polyaniline emeraldine salt and Polyaniline Zinc Oxide composite are comprehensively studied to compare their sensing ability towards ammonia, acetone, methanol and ethanol. Sensing ability is evaluated through thermodynamic, geometric and electronic parameters. A number of orientations are evaluated in search for the lowest energy structure.

Electronic structure of polythiophene gas sensors for chlorinated analytes.

Density functional theory studies are performed to investigate the response of polythiophene as a sensor for chlorinated gaseous analytes. Interaction of polythiophene with these analytes is studied from both H-side (dipole-dipole) and Cl-side (halogen bonding) of analyte to get the most stable interaction site. Inferences from interaction energy, natural bond orbital, and Mulliken charge analyses are in line with those from geometric analysis.