Review Article
A Review of Carbon Nanotubes-Based Gas Sensors
Table 1
Equilibrium tube-molecule distance , adsorption energy , and charge transfer of various molecules on , , and individual SWNTsa. The optimal adsorption sites are given in the table: T (top of a carbon atom), B (top of the centre of the C–C bond), C (top of the centre of carbon hexagon) [27]. Tube-molecule distance d is defined as the nearest distance between atoms on the molecule and the nanotube for T site, or the distance between the centre of the gas molecule and the centre of the carbon hexagon (carbon-carbon bond) for the C (B) site. The adsorption energy is defined as the total energy gained by molecule adsorption at equilibrium distance: Charge transfer denotes the total Mulliken charge number on the molecules, positive means charge transfer from molecule to tube.
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