Single‐walled carbon nanotubes filled with nickel halogenides: Atomic structure and doping effect

Abstract

Abstract NiX 2 @SWCNT (X = Cl, Br) nanostructures were prepared by capillary filling of single‐walled carbon nanotube channels with nickel halogenide melts with slow cooling down to room temperature for better crystallization. The HRTEM data indicated formation of well‐ordered 1D NiBr 2 crystals, with the experimental atomic structure representing a fragment of the bulk structure. The lattice constant coincides with the corresponding distance in bulk lattice. The 1D crystal structure was modeled using DFT within the PW‐GGA approach. According to the Raman, X‐ray photoelectron, X‐ray and optical absorption spectroscopic data and the DFT results obtained within the rigid band model, nickel halogenides display acceptor behavior with the corresponding charge transfer from the single‐walled carbon nanotube walls to the NiX 2 nanocrystals.