New Crystalline 1D Chain Encapsulated inside Nanotubes

Abstract

Encapsulation of different guest-species such as molecules, metals, pnictogen, halides, and transition metal chalcogenides inside nanotubes has been studied during the last decade and represents an exciting development of nanoengineering of novel materials and composites. The key mechanism of these experiments is the confinement effect induced by the cavities inside the nanotube, which makes the structure and detailed configuration of the quasi- one-dimensional (1D) nanostructures strongly dependent on the inner diameter of the nanotubes. Encapsulation of materials inside nanotubes has become a unique route toward novel quasi-1D nanostructures. In this talk, I will mainly present our recent results in the new crystalline 1D chain structure of germanium and silicon dichalcognides (Ge or Se X2) encapsulated within nanotubes. Utilizing the aberration-corrected scanning transmission electron microscopy (STEM), we investigated various type of the 1D tetrahedral Ge or Si X2 chains depending on the inner diameter of the nanotube. First-principles calculations based on density functional theory (DFT) provide insight into the 1D chain structure and stability of the materials, as well as their electronic structure. I will also present our efforts in synthesis of other crystalline materials encapsulated within nanotubes.