scholarly journals Insight into the Anchoring Effect of Two-Dimensional TiX2 (X = S, Se, Te) Materials for Lithium-Sulfur Batteries: A DFT Study

2021 ◽  
Author(s):  
Qiao Wu ◽  
Yuchao Chen ◽  
Xiaoqian Hao ◽  
Tianjiao Zhu ◽  
Yongan Cao ◽  
...  
Keyword(s):  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Discharge Process ◽  
Two Dimensional ◽  
Functional Theory ◽  
Anchoring Effect ◽  
Adsorption Behaviors ◽  
Lithium Sulfur Batteries ◽  
Metal Dichalcogenides ◽  
Lithium Sulfur

Abstract It is desirable to develop suitable anchoring materials to restrain the notorious shuttle phenomenon in lithium-sulfur (Li-S) batteries. Two-dimensional transition metal dichalcogenides (2D TMDs), especially TiS2, with excellent physicochemical properties have attracted much attention. Here, density functional theory (DFT) computations were performed to systematically explore the adsorption behaviors of lithium polysulfides (LiPSs) over TiX2 (X = S, Se, Te) monolayer. It is concluded that TiS2 shows the best anchoring effect owing to the strongest adsorption energy, and the intrinsic structures of LiPSs after adsorption could be preserved by calculating the decomposition energy. Moreover, the low diffusion energy barrier of Li2S on TiS2 surface is expected to accelerate the kinetics during the charge/discharge process. Based on a series of calculations and discussion, we can theoretically demonstrate that TiS2, as an anchoring material, has advantages over TiSe2 and TiTe2 in enhancing Li-S batteries performance.

Metal Dichalcogenide Nanomeshes: Structural, Electronic and Magnetic Properties

2021 ◽  
Author(s):  
Mohamed Helal ◽  
H. M. El-Sayed ◽  
Ahmed A Maarouf ◽  
Mohamed Fadlallah
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Transition Metal ◽  
Structural Stability ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Functional Theory ◽  
Electronic And Magnetic Properties ◽  
Metal Dichalcogenides

Motivated by the successful preparation of two-dimensional transition metal dichalcogenides (2D- TMDs) nanomeshes in the last three years, we use density functional theory (DFT) to study the structural stability, mechanical,...

Excitons in two-dimensional atomic layer materials from time-dependent density functional theory: mono-layer and bi-layer hexagonal boron nitride and transition-metal dichalcogenides

2020 ◽  
Vol 22 (5) ◽  
pp. 2908-2916 ◽  
Author(s):  
Yasumitsu Suzuki ◽  
Kazuyuki Watanabe
Keyword(s):  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Transition Metal Dichalcogenides ◽  
Atomic Layer ◽  
Time Dependent ◽  
Two Dimensional ◽  
Functional Theory ◽  
Mono Layer ◽  
Metal Dichalcogenides ◽  
Dependent Density

Time-dependent density functional theory has been applied to the calculation of absorption spectra for two dimensional atomic layer materials: mono-layer and bi-layer hexagonal boron nitride and mono-layer transition metal dichalcogenides.

scholarly journals Molecular Adsorption of NH3 and NO2 on Zr and Hf Dichalcogenides (S, Se, Te) Monolayers: A Density Functional Theory Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1215
Author(s):  
Shimeles Shumi Raya ◽  
Abu Saad Ansari ◽  
Bonggeun Shong
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Dielectric Materials ◽  
Molecular Adsorption ◽  
Two Dimensional ◽  
Functional Theory ◽  
Molecular Adsorbates ◽  
Semiconducting Properties ◽  
Metal Dichalcogenides

Due to their atomic thicknesses and semiconducting properties, two-dimensional transition metal dichalcogenides (TMDCs) are gaining increasing research interest. Among them, Hf- and Zr-based TMDCs demonstrate the unique advantage that their oxides (HfO2 and ZrO2) are excellent dielectric materials. One possible method to precisely tune the material properties of two-dimensional atomically thin nanomaterials is to adsorb molecules on their surfaces as non-bonded dopants. In the present work, the molecular adsorption of NO2 and NH3 on the two-dimensional trigonal prismatic (1H) and octahedral (1T) phases of Hf and Zr dichalcogenides (S, Se, Te) is studied using dispersion-corrected periodic density functional theory (DFT) calculations. The adsorption configuration, energy, and charge-transfer properties during molecular adsorption are investigated. In addition, the effects of the molecular dopants (NH3 and NO2) on the electronic structure of the materials are studied. It was observed that the adsorbed NH3 donates electrons to the conduction band of the Hf (Zr) dichalcogenides, while NO2 receives electrons from the valance band. Furthermore, the NO2 dopant affects than NH3 significantly. The resulting band structure of the molecularly doped Zr and Hf dichalcogenides are modulated by the molecular adsorbates. This study explores, not only the properties of the two-dimensional 1H and 1T phases of Hf and Zr dichalcogenides (S, Se, Te), but also tunes their electronic properties by adsorbing non-bonded dopants.

Interfacial properties of borophene contacts with two-dimensional semiconductors

2017 ◽  
Vol 19 (35) ◽  
pp. 23982-23989 ◽  
Author(s):  
Jie Yang ◽  
Ruge Quhe ◽  
Shenyan Feng ◽  
Qiaoxuan Zhang ◽  
Ming Lei ◽  
...  
Keyword(s):  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Dft Method ◽  
Interfacial Properties ◽  
Group Iv ◽  
Two Dimensional ◽  
Functional Theory ◽  
Group V ◽  
Two Dimensional Materials ◽  
Metal Dichalcogenides

Interfacial properties of β12phase borophene contacts with other common two-dimensional materials (transition-metal dichalcogenides, group IV-enes and group V-enes) have been systematically studied using a density functional theory (DFT) method.

Flexoelectricity in atomic monolayers from first principles

Nanoscale ◽  
2020 ◽  
Author(s):  
Shashikant Kumar ◽  
David Codony ◽  
Irene Arias ◽  
Phanish Suryanarayana
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Ab Initio ◽  
First Principles ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Functional Theory ◽  
Group Iii ◽  
Flexoelectric Effect ◽  
Metal Dichalcogenides

We study the flexoelectric effect in fifty-four select atomic monolayers using ab initio Density Functional Theory (DFT). Specifically, considering representative materials from each of Group III monochalcogenides, transition metal dichalcogenides...

scholarly journals Study of Structural and Electronic Properties of Intercalated Transition Metal Dichalcogenides Compound MTiS2 (M = Cr, Mn, Fe) by Density Functional Theory

2021 ◽  
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Electronic Properties ◽  
Density Of States ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Energy Band Structure ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Metal Dichalcogenides

In the present work, we have studied intercalated Transition Metal Dichalcogenides (TMDC) MTiS2 compounds (M = Cr, Mn, Fe) by Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA). We have computed the structural and electronic properties by using first principle method in QUANTUM ESPRESSO computational code with an ultra-soft pseudopotential. A guest 3d transition metal M (viz; Cr, Mn, Fe) can be easily intercalated in pure transition metal dichalcogenides compound like TiS2. In the present work, the structural optimization, electronic properties like the energy band structure, density of states (DoS), partial or projected density of states (PDoS) and total density of states (TDoS) are reported. The energy band structure of MTiS2 compound has been found overlapping energy bands in the Fermi region. We conclude that the TiS2 intercalated compound has a small band gap while the doped compound with guest 3d-atom has metallic behavior as shown form its overlapped band structure.

scholarly journals Strain-induced effects on the electronic properties of 2D materials

2020 ◽  
Vol 10 ◽  
pp. 184798042090256 ◽  
Author(s):  
Sara Postorino ◽  
Davide Grassano ◽  
Marco D’Alessandro ◽  
Andrea Pianetti ◽  
Olivia Pulci ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Many Body ◽  
Functional Theory ◽  
Metal Dichalcogenides ◽  
Extreme Sensitivity ◽  
Nonuniform Strain

Thanks to the ultrahigh flexibility of 2D materials and to their extreme sensitivity to applied strain, there is currently a strong interest in studying and understanding how their electronic properties can be modulated by applying a uniform or nonuniform strain. In this work, using density functional theory (DFT) calculations, we discuss how uniform biaxial strain affects the electronic properties, such as ionization potential, electron affinity, electronic gap, and work function, of different classes of 2D materials from X-enes to nitrides and transition metal dichalcogenides. The analysis of the states in terms of atomic orbitals allows to explain the observed trends and to highlight similarities and differences among the various materials. Moreover, the role of many-body effects on the predicted electronic properties is discussed in one of the studied systems. We show that the trends with strain, calculated at the GW level of approximation, are qualitatively similar to the DFT ones solely when there is no change in the character of the valence and conduction states near the gap.

scholarly journals Vibronic response of a spin-1/2 state from a carbon impurity in two-dimensional WS2

2020 ◽  
Author(s):  
Katherine Cochrane ◽  
Jun-Ho Lee ◽  
Christoph Kastl ◽  
Jonah Haber ◽  
Tianyi Zhang ◽  
...  
Keyword(s):  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Single Atom ◽  
Chemical Doping ◽  
Two Dimensional ◽  
Radical Ions ◽  
Defect States ◽  
Carbon Impurity ◽  
Carbon Impurities ◽  
Metal Dichalcogenides

Abstract We demonstrate the creation of a spin-1/2 state via the atomically controlled generation of magnetic carbon radical ions (CRIs) in synthetic two-dimensional transition metal dichalcogenides. Hydrogenated carbon impurities located at chalcogen sites introduced by chemical doping are activated with atomic precision by hydrogen depassivation using a scanning probe tip. In its anionic state, the carbon impurity exhibits a magnetic moment of 1 μB resulting from an unpaired electron populating a spin-polarized in-gap orbital. By inelastic tunneling spectroscopy and density functional theory we show that the CRI defect states couple to a small number of vibrational modes, including a local, breathing-type mode. The electron-phonon coupling strength critically depends on the spin state and differs for monolayer and bilayer WS2. These carbon radical ions in TMDs comprise a new class of surface-bound, single-atom spin-qubits that can be selectively introduced, are spatially precise, feature a well-understood vibronic spectrum, and are charge state controlled.

scholarly journals The Interaction of Hydrogen with the van der Waals Crystal γ-InSe

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2526 ◽  
Author(s):  
James Felton ◽  
Elena Blundo ◽  
Sanliang Ling ◽  
Joseph Glover ◽  
Zakhar R. Kudrynskyi ◽  
...  
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Theoretical Study ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Ion Source ◽  
Vibrational Modes ◽  
Functional Theory ◽  
Metal Dichalcogenides ◽  
Experimental And Theoretical Studies

The emergence of the hydrogen economy requires development in the storage, generation and sensing of hydrogen. The indium selenide ( γ -InSe) van der Waals (vdW) crystal shows promise for technologies in all three of these areas. For these applications to be realised, the fundamental interactions of InSe with hydrogen must be understood. Here, we present a comprehensive experimental and theoretical study on the interaction of γ -InSe with hydrogen. It is shown that hydrogenation of γ -InSe by a Kaufman ion source results in a marked quenching of the room temperature photoluminescence signal and a modification of the vibrational modes of γ -InSe, which are modelled by density functional theory simulations. Our experimental and theoretical studies indicate that hydrogen is incorporated into the crystal preferentially in its atomic form. This behaviour is qualitatively different from that observed in other vdW crystals, such as transition metal dichalcogenides, where molecular hydrogen is intercalated in the vdW gaps of the crystal, leading to the formation of “bubbles” for hydrogen storage.

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