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1. Vertically Stacked 2H‐1T Dual‐Phase MoS ₂ Microstructures during Lithium Intercalation: A First Principles Study

   https://doi.org/10.1111/jace.17367  

   Parida, Shayani; Mishra, Avanish; Chen, Jie; Wang, Jin; Dobley, Arthur; Carter, C_Barry; Dongare, Avinash_M (August 2020, Journal of the American Ceramic Society)

   Abstract Layered transition‐metal dichalcogenides (TMDs) have shown promise to replace carbon‐based compounds as suitable anode materials for Lithium‐ion batteries (LIBs) owing to facile intercalation and de‐intercalation of lithium (Li) during charging and discharging, respectively. While the intercalation mechanism of Li in mono‐ and bi‐layer TMDs has’ been thoroughly examined, mechanistic understanding of Li intercalation‐induced phase transformation in bulk or films of TMDs is still largely unexplored. This study investigates possible scenarios during sequential Li intercalation and aims to gain a mechanistic understanding of the phase transformation in bulk MoS₂using density functional theory (DFT) calculations. The manuscript examines the role of concentration and distribution of Li‐ions on the formation of dual‐phase 2H‐1T microstructures that have been observed experimentally. The study demonstrates that lithiation would proceed in a systematic layer‐by‐layer manner wherein Li‐ions diffuse into successive interlayer spacings to render local phase transformation of the adjacent MoS₂layers from 2H‐to‐1T phase in the multilayered MoS₂. This local phase transition is attributed to partial ionization of Li and charge redistribution around the metal atoms and is followed by subsequent lattice straining. In addition, the stability of single‐phase vs. multiphase intercalated microstructures, and the origins of structural changes accompanying Li‐ion insertion are investigated at atomic scales. 

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2. Solvothermal Synthesis of [Cr ₇ S ₈ (en) ₈ Cl ₂ ]Cl ₃  ⋅ 2H ₂ O with Magnetically Frustrated [Cr ₇ S ₈ ] ⁵⁺ Double‐Cubes**

   https://doi.org/10.1002/chem.202103761  

   Gamage, Eranga_H; Clark, Judith_K; Yazback, Maher; Cheng, Hai‐Ping; Shatruk, Michael; Kovnir, Kirill (December 2021, Chemistry – A European Journal)

   Abstract A novel transition metal chalcohalide [Cr₇S₈(en)₈Cl₂]Cl₃ ⋅ 2H₂O, with [Cr₇S₈]⁵⁺dicubane cationic clusters, has been synthesized by a low temperature solvothermal method, using dimethyl sulfoxide (DMSO) and ethylenediamine (en) solvents. Ethylenediamine ligand exhibits bi‐ and monodentate coordination modes; in the latter case ethylenediamine coordinates to Cr atoms of adjacent clusters, giving rise to a 2D polymeric structure. Although magnetic susceptibility shows no magnetic ordering down to 1.8 K, a highly negative Weiss constant,θ=−224(2) K, obtained from Curie‐Weiss fit of inverse susceptibility, suggests strong antiferromagnetic (AFM) interactions betweenS=3/2 Cr(III) centers. Due to the complexity of the system with (2S+1)⁷=16384 microstates from seven Cr³⁺centers, a simplified model with only two exchange constants was used for simulations. Density‐functional theory (DFT) calculations yielded the two exchange constants to beJ₁=−21.4 cm⁻¹andJ₂=−30.2 cm⁻¹, confirming competing AFM coupling between the shared Cr³⁺center and the peripheral Cr³⁺ions of the dicubane cluster. The best simulation of the experimental data was obtained withJ₁=−20.0 cm⁻¹andJ₂=−21.0 cm⁻¹, in agreement with the slightly stronger AFM exchange within the triangles of the peripheral Cr³⁺ions as compared to the AFM exchange between the central and peripheral Cr³⁺ions. This compound is proposed as a synthon towards magnetically frustrated systems assembled by linking dicubane transition metal‐chalcogenide clusters into polymeric networks. 

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3. Enhanced Li-Ion Rate Capability and Stable Efficiency Enabled by MoSe2 Nanosheets in Polymer-Derived Silicon Oxycarbide Fiber Electrodes

   https://doi.org/10.3390/nano12030553  

   Dey, Sonjoy; Mujib, Shakir Bin; Singh, Gurpreet (February 2022, Nanomaterials)

   Transition metal dichalcogenides (TMDs) such as MoSe2 have continued to generate interest in the engineering community because of their unique layered morphology—the strong in-plane chemical bonding between transition metal atoms sandwiched between two chalcogen atoms and the weak physical attraction between adjacent TMD layers provides them with not only chemical versatility but also a range of electronic, optical, and chemical properties that can be unlocked upon exfoliation into individual TMD layers. Such a layered morphology is particularly suitable for ion intercalation as well as for conversion chemistry with alkali metal ions for electrochemical energy storage applications. Nonetheless, host of issues including fast capacity decay arising due to volume changes and from TMD’s degradation reaction with electrolyte at low discharge potentials have restricted use in commercial batteries. One approach to overcome barriers associated with TMDs’ chemical stability functionalization of TMD surfaces by chemically robust precursor-derived ceramics or PDC materials, such as silicon oxycarbide (SiOC). SiOC-functionalized TMDs have shown to curb capacity degradation in TMD and improve long term cycling as Li-ion battery (LIBs) electrodes. Herein, we report synthesis of such a composite in which MoSe2 nanosheets are in SiOC matrix in a self-standing fiber mat configuration. This was achieved via electrospinning of TMD nanosheets suspended in pre-ceramic polymer followed by high temperature pyrolysis. Morphology and chemical composition of synthesized material was established by use of electron microscopy and spectroscopic technique. When tested as LIB electrode, the SiOC/MoSe2 fiber mats showed improved cycling stability over neat MoSe2 and neat SiOC electrodes. The freestanding composite electrode delivered a high charge capacity of 586 mAh g−1electrode with an initial coulombic efficiency of 58%. The composite electrode also showed good cycling stability over SiOC fiber mat electrode for over 100 cycles. 

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4. Influence of Rhenium Concentration on Charge Doping and Defect Formation in MoS ₂

   https://doi.org/10.1002/aelm.202400403  

   Munson, Kyle T; Torsi, Riccardo; Habis, Fatimah; Huberich, Lysander; Lin, Yu‐Chuan; Yuan, Yue; Wang, Ke; Schuler, Bruno; Wang, Yuanxi; Asbury, John B; et al (March 2025, Advanced Electronic Materials)

   Substitutionally doped transition metal dichalcogenides (TMDs) are essential for advancing TMD‐based field effect transistors, sensors, and quantum photonic devices. However, the impact of local dopant concentrations and dopant–dopant interactions on charge doping and defect formation within TMDs remains underexplored. Here, a breakthrough understanding of the influence of rhenium (Re) concentration is presented on charge doping and defect formation in MoS₂monolayers grown by metal–organic chemical vapor deposition (MOCVD). It is shown that Re‐MoS₂films exhibit reduced sulfur‐site defects, consistent with prior reports. However, as the Re concentration approaches ⪆2 atom%, significant clustering of Re in the MoS₂is observed. Ab Initio calculations indicate that the transition from isolated Re atoms to Re clusters increases the ionization energy of Re dopants, thereby reducing Re‐doping efficacy. Using photoluminescence (PL) spectroscopy, it is shown that Re dopant clustering creates defect states that trap photogenerated excitons within the MoS₂lattice, resulting in broad sub‐gap emission. These results provide critical insights into how the local concentration of metal dopants influences carrier density, defect formation, and exciton recombination in TMDs, offering a novel framework for designing future TMD‐based devices with improved electronic and photonic properties. 

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5. Wafer-scale 2D PtTe ₂ layers for high-efficiency mechanically flexible electro-thermal smart window applications

   https://doi.org/10.1039/D0NR01845G  

   Okogbue, Emmanuel; Ko, Tae-Jun; Han, Sang Sub; Shawkat, Mashiyat Sumaiya; Wang, Mengjing; Chung, Hee-Suk; Oh, Kyu Hwan; Jung, Yeonwoong (May 2020, Nanoscale)

   null (Ed.)

   Two-dimensional (2D) transition metal dichalcogenide (TMD) layers have gained increasing attention for a variety of emerging electrical, thermal, and optical applications. Recently developed metallic 2D TMD layers have been projected to exhibit unique attributes unattainable in their semiconducting counterparts; e.g. , much higher electrical and thermal conductivities coupled with mechanical flexibility. In this work, we explored 2D platinum ditelluride (2D PtTe 2 ) layers – a relatively new class of metallic 2D TMDs – by studying their previously unexplored electro-thermal properties for unconventional window applications. We prepared wafer-scale 2D PtTe 2 layer-coated optically transparent and mechanically flexible willow glasses via a thermally-assisted tellurization of Pt films at a low temperature of 400 °C. The 2D PtTe 2 layer-coated windows exhibited a thickness-dependent optical transparency and electrical conductivity of >10 6 S m −1 – higher than most of the previously explored 2D TMDs. Upon the application of electrical bias, these windows displayed a significant increase in temperature driven by Joule heating as confirmed by the infrared (IR) imaging characterization. Such superior electro-thermal conversion efficiencies inherent to 2D PtTe 2 layers were utilized to demonstrate various applications, including thermochromic displays and electrically-driven defogging windows accompanying mechanical flexibility. Comparisons of these performances confirm the superiority of the wafer-scale 2D PtTe 2 layers over other nanomaterials explored for such applications. 

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