Molecular Dynamics Simulation of Bismuth Telluride Exfoliation Mechanisms in Different Ionic Liquid Solvents

Abstract

Bismuth telluride (BiTe) is a well-known thermoelectric material with potential applications in several different emerging technologies. The bulk structure is composed of stacks of quintuple sheets (with weak interactions between neighboring sheets), and the performance of the material can be significantly enhanced if exfoliated into two-dimensional nanosheets. In this study, eight different imidazolium-based ionic liquids are evaluated as solvents for the exfoliation and dispersion of BiTe at temperatures ranging from 350 to 550 K. Three distinct exfoliation mechanisms are evaluated (pulling, shearing, and peeling) using steered molecular dynamics simulations, and we predict that the peeling mechanism is thermodynamically the most favorable route. Furthermore, the [TfN]-based ionic liquids are particularly effective at enhancing the exfoliation, and this performance can be correlated to the unique molecular-level solvation structures developed at the BiTe surfaces. This information helps provide insight into the molecular origins of exfoliation and solvation involving BiTe (and possibly other layered chalcogenide materials) and ionic liquid solvents.

Solution-Based Synthesis and Processing of Metal Chalcogenides for Thermoelectric Applications

“…Bi 2 Te 3 nanoplatelets in [C 4 mim]Cl were synthesized at 0.05 wt % through 1-h tip sonication at a temperature of 80−150 • C and a power of 225-600 W. After sonication, as-synthesized nanoplatelets with a thickness of 1 to 2 µm were exfoliated to 15 ± 8 nm nanosheets. Later, the same group examined different exfoliation solvents and dispersion of Bi 2 Te 3 from eight imidazolium-based ionic liquids at temperatures between 350 to 550 K [46]. For Bi2Te3, each crystal layer is made up of approximately 1-nm thick quintuple sheets where the five atoms is covalently bonded in the order of Te1-Bi-Te2-Bi-Te1.…”

Exfoliation of hexagonal boron nitride assisted with hierarchical ionic fragments by ball‐milling for achieving high thermally conductive polymer nanocomposite

“…[21] Traditional ionic liquids have already been employed as environmentally friendly alternatives solvents for h-BN exfoliation owing to their ion intercalation, cation-interactions and matched surface energy. [22][23][24][25] Nevertheless, the high viscosity and monotonous ion composition of traditional ionic liquids have adverse on exfoliating h-BN. While, CPs derived ionic liquid analogues with hierarchical ionic fragments via in situ phase transitions are expected to be promising candidates for BNNSs preparation.…”

Nonaqueous Solvent Adsorption on Transition Metal Surfaces with Density Functional Theory: Interaction of N,N-Dimethylformamide (DMF), Tetrahydrofuran (THF), and Dimethyl Sulfoxide (DMSO) with Ag, Cu, Pt, Rh, and Re Surfaces

“…Competitive adsorption or poisoning is an obvious mechanism by which the solvent/electrolyte affects surface concentrations of intermediates involved in the reaction; solvent molecules compete for limited adsorption sites with the reactive surface species . There are also possible adsorbate–adsorbate interaction effects, in which the presence of an adsorbed solvent could change the binding energies of other nearby adsorbates through dipole, steric, or other interactions, effectively modifying properties of the catalyst. ,, Additionally, the partial solvation of adsorbed species at the catalyst–solvent interface can significantly affect the reaction energetics, and therefore the rates, of elementary steps. , Other possible effects are closely related to the interfacial solvation and electrical double layer behavior, such as the interaction and structure of electrolyte ions near a charged electrode. ,− The presence of the solvent can structurally modify the surface, as well as the relative surface energies and thereby the shapes of nanoparticles, affecting catalytic, electrochemical, and other properties. − ,− …”