Metal–Organic Chemical Vapor Depostion Synthesis of Hollow Inorganic‐Fullerene‐Type MoS₂ and MoSe₂ Nanoparticles

Abstract

In materials with low-dimensional structures, the instability of the weakly bonded layered slabs against folding, and the saturation of dangling bonds in finite layers, leads to the formation of a variety of nanostructures with spherical or cylindrical shapes. In analogy to nested carbon fullerenes [1] and nanotubes, [2] Tenne and co-workers [3,4] discovered related MQ 2 -based (M = early transition metal, Q = S, Se) concentric closed-shell materials, which laid the foundation for the entire field of nanostructures based on inorganic materials.[5] Substantial progress has been made in the application of MoS 2 and WS 2 nanoparticles as lubricants [6±9] and heterogeneous catalysts, [10,11] and MoS 2 nanotubes as electrochemical hydrogen-storage [12] and lithium-intercalation materials. [13,14] During the past few years a huge body of experimental evidence has been accumulated that suggests the phase diagram of the elements that form layered compounds includes new phases of hollow and closed nanostructures. Provided that the crystal growth is limited and the crystallites remain smaller than a critical size (ca. 100 nm), these nanostructures are the thermodynamically preferred phases. In other words, a key step in the preparation of nanostructured layered materials is the restricted growth of the newly formed two-dimensional (2D) crystallites. [15,16] Various strategies have been developed to prepare nanostructured metal chalcogenides, including sulfides and selenides, through different growth mechanisms. A characteristic feature of all closed-shell structures is that high reaction temperatures (> 800 C) or large activation energies are needed to overcome the activation barrier associated with the bending of the otherwise flat 2D layers.[ can provide large activation energies in a very short period, such as electron irradiation, [19] laser ablation, [20] microwave plasma, [21] arc discharge, [22] and pulsed-laser vaporization, [23,24] have been used to synthesize a variety of inorganic fullerene (IF)-like nanostructures. Schuffenhauer et al. [25] have synthesized nested fullerene-like NbS 2 by the reaction between NbCl 5 vapor and H 2 S gas at 400 C followed by further heat treatment at 550 C. Similarly, Coleman et al. [26] have synthesized ReS 2 fullerene-like nanoparticles by sulfidization of ReO 2 obtained from ReO 3 decomposition. As the above methods have to rely mostly on high temperatures and/or complicated processes they may not be optimally suited for the large-scale preparation of nanostructured metal chalcogenides with a minimum amount of side products. On the other hand, as the mechanical, physical, and catalytic properties of nanostructured chalcogenides strongly depend on their size and shape, it is desirable to devise synthetic procedures that enable significant control of the particle size and morphology. From an applications point of view, the focus on nanoparticle growth will be on high-purity, high-yield, and, therefore, low-cost products.In this contribution we report on the facile, large-scale s...

Discrete quantum dot like emitters in monolayer MoSe2: Spatial mapping, magneto-optics, and charge tuning

“…[4][5][6] The 2D host materials have the advantage of being cost efficient, with highly tunable properties 3,7 and optical access to the electron valley index in momentum space, 8,9 an additional degree of freedom compared to other solid state qubits in III-V quantum dots (QDs) or NV centres in diamond, for example. There are several approaches to achieve 3D quantum confinement, such as patterning TMD MLs, 10 chemically synthesized TMD nano-crystals, [11][12][13][14][15][16] and defect engineering. [17][18][19][20] In photoluminescence (PL) experiments at T ¼ 4 K, we observe QD-like, discrete emission lines (full width at half maximum (FWHM) typ.…”

Synthesis and functionalization of chalcogenide nanotubes

“…The synthesis of MoS 2 and MoSe 2 fullerene-like particles was carried out by using molybdenum hexacarbonyl (Mo(CO) 6 ) and elemental sulfur/selenium as the precursors [75]. The reaction was carried out in two steps.…”

Gas-phase synthesis of inorganic fullerene-like structures and inorganic nanotubes

“…A case in a point is the facile, large-scale synthesis of hollow IF-MoS 2 and MoSe 2 nanoparticles, which was reported by Tremel and co-workers [45]. This reaction was carried out by a metal-organic chemical vapor deposition (MOCVD) approach, wherein Mo(CO) 6 and elemental S/Se were used as the starting materials.…”