The structural, energetic and electronic properties of doped carbon nanotubes by encapsulation of MCp2 (M = Fe, Co, Ni): A theoretical investigation

Metallocenes can be encapsulated inside the carbon nanotubes. The structural, energetic and electronic properties of organometallic MCp2@SWCNT are obtained from DFT method. We verify that such encapsulation is noncovalent functionalization, and examined binding energies and charge transfers of MCp2@(16, 0)SWCNT systems. Consistent with recent experimental findings, the optimal distance between FeCp2 center and near tube-wall is 4.7 (5.1) Å for the configuration where MCp2’s fivefold axis is parallel (vertical) to nanotube axis, while the minimal diameter is 9.4 (10.2) Å to exothermically encapsulate FeCp2 molecules. Finally we clarify the doping effects near the band gap by encapsulations of CoCp2 and NiCp2.