Premium
The structure and continuous stoichiometry change of 1DTbBr x @SWCNTs
Author(s) -
KISELEV N.A.,
KUMSKOV A.S.,
ZHIGALINA V.G.,
VASILIEV A.L.,
SLOAN J.,
FALALEEV N.S.,
VERBITSKIY N.I.,
ELISEEV A.A.
Publication year - 2016
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/jmi.12348
Subject(s) - materials science , monoclinic crystal system , raman spectroscopy , crystallography , stoichiometry , high resolution transmission electron microscopy , crystal (programming language) , carbon nanotube , crystal structure , bromine , nanotechnology , chemistry , transmission electron microscopy , programming language , physics , computer science , optics , metallurgy
Summary HRTEM and HAADF STEM of 1DTbBr x @SWCNT meta‐nanotubes reveal three structural modifications of 1D nanocrystals within single wall carbon nanotube channels attributed to a different stoichiometry of the guest crystal. For SWCNTs with diameters D m > 1.4 nm a most complete tetragonal unit cell is observed. When crystallization occurs inside SWCNT with D m < 1.4 nm 1D TbBr x crystal deforms a nanotube to elliptical shape in cross section. In this case the 1D crystal unit cell becomes monoclinic, with possible loss of a part of bromine atoms. Two modifications of a monoclinic unit cell appear. One of them is characterized by single or pair vacancies in the structure of the 1D crystal. Another structure is explained by peripheral and central bromine atoms loss. An appearance of such modifications can be stimulated by electron irradiation. The loss of bromine atoms is in agreement with chemical analysis data. Electronic properties of obtained meta‐nanotubes are investigated using optical absorption and Raman spectroscopy. It is shown that intercalation of terbium bromide into SWCNTs leads to acceptor doping of SWCNTs. According to local EDX analysis and elemental mapping this doping can arise from significant stoichiometry change in 1D nanocrystal indicating an average Tb:Br atomic ratio of 1:2.8 ± 0.1.