scholarly journals Structural and High-Pressure Properties of Rheniite (ReS2) and (Re,Mo)S2

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 207
Author(s):  
Jordi Ibáñez-Insa ◽  
Tomasz Woźniak ◽  
Robert Oliva ◽  
Catalin Popescu ◽  
Sergi Hernández ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Density Functional ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Compression Behavior ◽  
Novel Device ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal ◽  
Mo Content

Rhenium disulfide (ReS2), known in nature as the mineral rheniite, is a very interesting compound owing to its remarkable fundamental properties and great potential to develop novel device applications. Here we perform density functional theory (DFT) calculations to investigate the structural properties and compression behavior of this compound and also of the (Re,Mo)S2 solid solution as a function of Re/Mo content. Our theoretical analysis is complemented with high-pressure X-ray diffraction (XRD) measurements, which have allowed us to reevaluate the phase transition pressure and equation of state of 1T-ReS2. We have observed the 1T-to-1T’ phase transition at pressures as low as ~2 GPa, and we have obtained an experimental bulk modulus, B0, equal to 46(2) GPa. This value is in good agreement with PBE+D3 calculations, thus confirming the ability of this functional to model the compression behavior of layered transition metal dichalcogenides, provided that van der Waals corrections are taken into account. Our experimental data and analysis confirm the important role played by van der Waals effects in the high-pressure properties of 1T-ReS2.

scholarly journals Carrier multiplication in van der Waals layered transition metal dichalcogenides

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ji-Hee Kim ◽  
Matthew R. Bergren ◽  
Jin Cheol Park ◽  
Subash Adhikari ◽  
Michael Lorke ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
High Energy ◽  
Ultrafast Optical ◽  
Photovoltaic Energy Conversion ◽  
Carrier Multiplication ◽  
Ultrafast Optical Spectroscopy ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

AbstractCarrier multiplication (CM) is a process in which high-energy free carriers relax by generation of additional electron-hole pairs rather than by heat dissipation. CM is promising disruptive improvements in photovoltaic energy conversion and light detection technologies. Current state-of-the-art nanomaterials including quantum dots and carbon nanotubes have demonstrated CM, but are not satisfactory owing to high-energy-loss and inherent difficulties with carrier extraction. Here, we report CM in van der Waals (vdW) MoTe2 and WSe2 films, and find characteristics, commencing close to the energy conservation limit and reaching up to 99% CM conversion efficiency with the standard model. This is demonstrated by ultrafast optical spectroscopy with independent approaches, photo-induced absorption, photo-induced bleach, and carrier population dynamics. Combined with a high lateral conductivity and an optimal bandgap below 1 eV, these superior CM characteristics identify vdW materials as an attractive candidate material for highly efficient and mechanically flexible solar cells in the future.

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.

Heteroepitaxy Between Lattice Mismatched Materials with Van Der Waals Interactions

1990 ◽  
Vol 198 ◽  
Author(s):  
Atsushi Koma
Keyword(s):  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Three Dimensional ◽  
Matching Condition ◽  
Van Der Waals Interactions ◽  
Heteroepitaxial Growth ◽  
Lattice Matching ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal ◽  
Growth Methods

ABSTRACTThe lattice matching condition encountered usually in the heteroepitaxial growth has been proved to be relaxed drastically, if one uses the interface having van der Waals nature. Such interface can be realized on a cleaved face of a layered material or a quasi-one dimensional material and on a surface of a dangling-bond-terminated three dimensional material. Various kinds of heterostructures, which cannot be made by conventional growth methods, can be fabricated by using a variety of layered transition metal dichalcogenides, in which there exist superconducting, metallic, semiconducting or insulating layered materials. Moreover those heterostructures have been found to be grown on such an ordinary three-dimensional material as GaAs, if the dangling bonds on its surface are terminated by suitable atoms.

Kinetics and Atomic Mechanisms of Structural Phase Transformations in Photoexcited Monolayer TMDCs

MRS Advances ◽  
2018 ◽  
Vol 3 (6-7) ◽  
pp. 345-350
Author(s):  
Aravind Krishnamoorthy ◽  
Lindsay Bassman ◽  
Rajiv K. Kalia ◽  
Aiichiro Nakano ◽  
Fuyuki Shimojo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Density Functional ◽  
Structural Phase ◽  
Transition Metal Dichalcogenides ◽  
Optical Excitation ◽  
Metal Phase ◽  
Rapid Phase ◽  
Metal Dichalcogenides ◽  
Metal Phase Transition

ABSTRACTRapid transitions between semiconducting and metallic phases of transition-metal dichalcogenides are of interest for 2D electronics applications. Theoretical investigations have been limited to using thermal energy, lattice strain and charge doping to induce the phase transition, but have not identified mechanisms for rapid phase transition. Here, we use density functional theory to show how optical excitation leads to the formation of a low-energy intermediate crystal structure along the semiconductor-metal phase transition pathway. This metastable crystal structure results in significantly reduced barriers for the semiconducting-metal phase transition pathway leading to rapid transition in optically excited crystals.

Rational Design of Monolayer Transition Metal Dichalcogenide@Fullerene van der Waals Photovoltaic Heterojunctions with the Aid of Time-Domain Density Functional Theory Simulations

2021 ◽  
Author(s):  
Hong-Jun Zhou ◽  
Dong-Hui Xu ◽  
Qin-Hong Yang ◽  
Xiangyang Liu ◽  
Ganglong Cui ◽  
...  
Keyword(s):  
Transition Metal ◽  
Time Domain ◽  
Density Functional ◽  
Rational Design ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Photovoltaic Devices ◽  
Functional Theory ◽  
Metal Dichalcogenides

Van der Waals heterojunctions formed by transition metal dichalcogenides (TMDs) and fullerenes are promising candidates for novel photovoltaic devices due to the excellent optoelectronic properties of both TMDs and fullerenes....

scholarly journals Rolling the WSSe Bilayer into Double-Walled Nanotube for the Enhanced Photocatalytic Water-Splitting Performance

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 705
Author(s):  
Lin Ju ◽  
Jingzhou Qin ◽  
Liran Shi ◽  
Gui Yang ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Density Functional Theory Calculations ◽  
Stable Configuration ◽  
Photocatalytic Water Splitting ◽  
Stacking Pattern ◽  
Metal Dichalcogenides ◽  
Photocatalytic Performances ◽  
Carrier Separation

For the emerging Janus transition metal dichalcogenides (TMD) layered water-splitting photocatalysts, stacking the monolayers to form bilayers has been predicted to be an effective way to improve their photocatalytic performances. To achieve this, the stacking pattern plays an important role. In this work, by means of the density functional theory calculations, we comprehensively estimate energetical stability, light absorption and redox capacity of Janus WSSe bilayer with different stacking patterns. Unfortunately, the Janus WSSe bilayer with the most stable configuration recover the out-of-plane symmetry, which is not in favor of the photocatalytic reactions. However, rolling the Janus WSSe bilayer into double-walled nanotube could stabilize the appropriate stacking pattern with an enhanced instinct dipole moment. Moreover, the suitable band edge positions, high visible light absorbance, outstanding solar-to-hydrogen efficiency (up to 28.48%), and superior carrier separation promise the Janus WSSe double-walled nanotube the potential for the photocatalytic water-splitting application. Our studies not only predict an ideal water-splitting photocatalyst, but also propose an effective way to improve the photocatalytic performances of Janus layered materials.

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