In Situ Characterization of Transformations in Nanoscale Layered Metal Chalcogenide Materials: A Review

Abstract

Layered metal chalcogenide materials, such as MoS2 and Bi2Te3, have found important applications as 2D materials in emerging electronic devices. To create nanoscale layered chalcogenide materials with precisely controlled structures and properties, it is critical to understand and control how they evolve and transform under various conditions. This Minireview presents an overview of recent research focused on using in situ characterization to understand the atomic‐scale details of transformations during growth, under exposure to reactive chemical and thermal environments, and on interfacing with other materials. These efforts have used techniques including in situ transmission electron microscopy (TEM), X‐ray spectroscopy, and optical methods to understand nanoscale transformations. These in situ studies have provided a substantially improved understanding of transformation mechanisms in layered chalcogenide materials, which is an important step toward the use of these interesting materials in a variety of electronic and electrochemical devices.

Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy

“…The extension of TEM capabilities into in situ/operando imaging and spectroscopy has enabled real-time observation and monitoring of the structural evolution of materials, including sublimation, formation, and growth of nanoscale defects; − nanoscale switching phenomena such as ferroelectric and resistive switching; phase transitions; light-driven chemical transformations; electrochemical reactions in lithium-ion batteries; , the electric-field response of domain walls; nanoscale mapping of the charge recombination; and electrical triggered structural transformations such as nucleation of polarized domains . Several reviews cover the basics, challenges, progress, and opportunities that each of these in situ techniques can offer. − …”

Solvent modulated self‐assembled VS 2 layered microstructure for electrocatalytic water and urea decomposition

“…26,27 Additionally, it also has other benefits, including easy fabrication, low cost, and environmentally friendliness. 28,29 Among the sulfides, vanadium disulfide (VS 2 ) is a hexagonal graphite-like structure composed of S-V-S layers sandwiched between two sulfur layers via van der Waals forces. Moreover, it is characterized by excellent electrical conductivity, weak interlayer interactions, and high specific surface area with edge exposed atoms.…”

“…To this end, layered metal‐sulfides may be a good selection due to their outstanding conductivity, attainable oxidation states for redox reactions, abundant edges, and aligned structure 26,27 . Additionally, it also has other benefits, including easy fabrication, low cost, and environmentally friendliness 28,29 . Among the sulfides, vanadium disulfide (VS 2 ) is a hexagonal graphite‐like structure composed of S‐V‐S layers sandwiched between two sulfur layers via van der Waals forces.…”

Melting, Crystallization, and Alloying Dynamics in Nanoscale Bismuth Telluride

“…29 While computational work has been conducted to model transformations in LMCs, the complex bonding interactions associated with the vdW gap and a lack of accurate experimental data limit the scope of such models. 30,31 There is thus a need for in situ experimental techniques 32 that reveal nanoscale transformation mechanisms in LMCs under various conditions without significant material loss or damage.…”

“…To understand transformation mechanisms under such stimuli, previous studies have focused on the crystallization of LMCs during growth from precursors, heat- and radiation-induced transformations, environmental degradation, , intercalation − and alloying reactions, , as well as reactions between contact metals and LMCs. ,, Imaging such transformations at high spatial and temporal resolution without altering the intrinsic properties of the LMC is necessary but challenging, as significant material loss can occur through radiolysis or heating when imaged with electron microscopy . While computational work has been conducted to model transformations in LMCs, the complex bonding interactions associated with the vdW gap and a lack of accurate experimental data limit the scope of such models. , There is thus a need for in situ experimental techniques that reveal nanoscale transformation mechanisms in LMCs under various conditions without significant material loss or damage.…”