Engineering polymorphs in colloidal metal dichalcogenides: precursor-mediated phase control, molecular insights into crystallisation kinetics and promising electrochemical activity

Abstract

Controlling the crystal phase in layered transition metal dichalcogenides (TMD) is critical for their diverse, flexible applications. However, due to the thermodynamic stability of 2H over other polymorphs, fine synthesis...

Functional Alkali Metal-Based Ternary Chalcogenides: Design, Properties, and Opportunities

“…Given this, a very interesting avenue to explore is the use of solution-based approaches for synthesizing ABZ compositions, for instance, solvothermal or hydrothermal approaches. In our own experience in exploring the 1T′ metastable phase synthesis of transition metal chalcogenides, we have found that colloidal synthesis gives better control in phase engineering in materials such as MoS 2 and WS 2 compared to the chemical exfoliation approach. ,, In colloidal synthesis, molecular precursors and organic surfactants/ligands are heated at high temperatures, where precursors decompose to form monomers, which then nucleate and grow as NCs. Colloidal synthesis chemistry offers exquisite control over the size, shape, and composition of crystals through the precursor–ligand–temperature interplay.…”

“…In our group, the research is focused on functional nanomaterial design based on metal chalcogenides for energy conversion and storage applications. − In our current search for stable and synthesizable multielement inorganic nanostructures (based on alkali metal chalcogenides that exhibit interesting optoelectronic properties), we limit the material composition to ternary systems. Multinary chalcogenides provide unlimited control with which one can influence the composition-dependent parameters (e.g., crystal structure, particle dimensions, and electronic structure) and can simultaneously complicate the search for conceivable materials.…”

Colloidal Synthesis of Multinary Alkali-Metal Chalcogenides Containing Bi and Sb: An Emerging Class of I–V–VI2 Nanocrystals with Tunable Composition and Interesting Properties

“…In the colloidal hot injection (HI) method, efficient control over nucleation and growth stages can be achieved by choosing suitable precursors and reaction parameters. − Several multinary metal chalcogenide compositions such as Cu 2 FeSnSe 4 , Cu 2 MSnS 4 (M = Co, Fe, Ni, Zn, Cd), Cu 2 ZnSn­(S 1– x Se x ) 4 , CuIn 1– x Gax­(S 1– y Se y ) 2 , Cu α Zn β Sn γ Se δ , Ag-In-Zn-S, etc. have been achieved in NC forms by using the HI method. ,− The compositional library has been further extended using attractive cation exchange (CE) processes. − For the above-mentioned systems, Ag 2 E or Cu 2 E (E = S, Se, Te) form as initial nuclei possessing highly mobile Ag + or Cu + cations on the rigid chalcogen sublattice.…”

Panoply of Ni-Doping-Induced Reconstructions, Electronic Phases, and Ferroelectricity in 1T-MoS2

“…52,53 Other possible techniques are epitaxy on a Ni-doped monolayer or other suitable substrate 54 or stabilization with appropriate ligands. 55 Experiments have shown that 1T phases can be stable even under reaction conditions of ion exchange 53 or etching of S atoms. 31 Such structures, including the potential analogues involving other transition-metal dichalcogenides and transitionmetal dopants, are interesting for applications in electronics, optics, energy storage, and catalysis and may offer other intriguing properties.…”

“…This process of removal of adatoms is akin to the methods used to synthesize 1T phases via Li or K atoms, or to deintercalate transition metals, and undoing Ni substitution of Mo or S seems plausible via ion-exchange methods that have been used to interconvert different TMDs and produce 1T-MoS 2 nanoflowers . Therefore, the route used in our calculations may also constitute a viable method for experimental synthesis, though stabilization by epitaxy or ligands are also possible strategies. Most of the structures relaxed to previously known phases (2 × 2 or 3 × 3 ), ,,, while a few reconstructions were not found in the literature (Table , Figure ).…”