1D lead iodide crystals encapsulated within single walled carbon nanotubes

The structure and binding energies of lead iodide crystals encapsulated within single-walled carbon noanotubes are studied using density functional theory. Calculations were performed on the simulated PbI₂ structure encapsulated within a (12,12) single-walled nanotube, to investigate the perturbations on the PbI₂ crystal and tube structure and electronic structure, and to estimate the binding energy. The calculation confirms the structure as a. single chain of PbI₆ octahedra bound by two chains of PbI₅ square pyramids. The calculated binding energy shows that the encapsulation is noncovalent. Minimal charge transfer is observed between nanotube and the PbI₂ crystals. The band gap is shown to increase from the bulk to the encapsulated structure.