First-principles study of ZnO cluster-decorated carbon nanotubes

We have investigated the structural, electronic and carbon monoxide (CO) detection properties of the ZnO cluster-decorated single-walled carbon nanotubes (SWCNTs) by using density functional theory (DFT). The stable structures of hybrid ZnO/SWCNT materials are that the ZnO cluster plane is perpendicular to the surface of SWCNTs with the Zn atoms towards the SWCNTs (Zn atom above axial C-C bond or above the C atom). For the ZnO cluster-decorated semiconducting SWCNTs, the SWCNTs present p-type characteristics which may lead to the decrease of conductance upon illumination with ultraviolet (UV) light. The CO can be adsorbed on the hybrid ZnO/SWCNT materials due to the charge transfer between them. Compared with isolated ZnO clusters or bare SWCNTs, the ZnO/SWCNT network would have excellent CO detection ability due to their suitable adsorption energy and conductivity.