The interactions between four different graphenes (including pristine, B- or Ndoped

and defective graphenes) and small gas molecules (CO, NO, NO2 and NH3)

were investigated by using density functional computations. The structural and

electronic properties of the graphene–molecule adsorption adducts were strongly

dependent upon the graphene structure and the molecular adsorption configuration.

All four gas molecules showed much stronger adsorption on the doped or defective

graphenes than that on the pristine graphene. The defective graphene exhibited the

highest adsorption energy with CO, NO and NO2 molecules, while the B-doped

graphene gives the tightest binding with NH3. Meanwhile, the strong interactions

between the adsorbed molecules and the modified graphenes induce dramatic

changes to graphene's electronic properties. The transport behaviour of a gas sensor

using B-doped graphene exhibited a sensitivity two orders of magnitude higher

than that of pristine graphene. This work revealed that the sensitivity of graphenebased

chemical gas sensors could be drastically improved by introducing the

appropriate dopant or defect. Improving Gas Sensing Properties of Graphene by Introducing Dopants and

Defects: a First-Principles Study. Y.H.Zhang, Y.B.Chen, K.G.Zhou, C.H.Liu,

J.Zeng, H.L.Zhang, Y.Peng: Nanotechnology, 2009, 20[18], 185504