Atomic Defects in Monolayer Titanium Carbide (Ti3C2Tx) MXene.
The 2D transition metal carbides or nitrides, or MXenes, are emerging as a group of materials showing great promise in lithium ion batteries and supercapacitors. Until now, characterization and properties of single-layer MXenes have been scarcely reported. Here, using scanning transmission electron microscopy, we determined the atomic structure of freestanding monolayer Ti3C2Txflakes prepared via the minimally intensive layer delamination method and characterized different point defects that are prevalent in the monolayer flakes. We determine that the Ti vacancy concentration can be controlled by the etchant concentration during preparation. Density function theory-based calculations confirm the defect structures and predict that the defects can influence the surface morphology and termination groups, but do not strongly influence the metallic conductivity. Using devices fabricated from single- and few-layer Ti3C2TxMXene flakes, the effect of the number of layers in the flake on conductivity has been demonstrated.
Xiahan
X
Sang
Yu
Y
Xie
Ming-Wei
MW
Lin
Department of Materials Science and Engineering, and A. J. Drexel Nanomaterials Institute, Drexel University , Philadelphia, Pennsylvania 19104, United States.
Mohamed
M
Alhabeb
Department of Materials Science and Engineering, and A. J. Drexel Nanomaterials Institute, Drexel University , Philadelphia, Pennsylvania 19104, United States.
Katherine L
KL
Van Aken
Department of Materials Science and Engineering, and A. J. Drexel Nanomaterials Institute, Drexel University , Philadelphia, Pennsylvania 19104, United States.
Yury
Y
Gogotsi
Paul R C
PRC
Kent
Kai
K
Xiao
Raymond R
RR
Unocic
MXene; conductivity; defect; minimally intensive layer delamination (MILD); vacancy