Tungsten Disulfide (WS2) Pristine Flakes in Solution, 100 ML
WS2 Pristine Flakes are nanoscale crystals dispersed in ethanol/water solution. If separated from solution, nano-WS2 forms bright-green crystals, that look different from silver-grey crystals of bulk WS2.
Lateral Size: 50-150 nm
Thickness: 1-4 monolayers
Purity in dry phase: >99%
Solution Concentration: 26 mg/L
Solution is stable under ambient conditions
This solution can be easily deposited onto a substrate or surface of your choice to form a thin film coating.
SEM image of thin-film WS2 after the solution was used to coat SiO2
UV-Visible Absorption Spectrum
Bulk WS2 forms dark gray hexagonal crystals with a layered structure. They are not chemically active and can only be dissolved by a mixture of nitric and hydrofluoric acids. Each W(IV) center of WS2 is occupying a trigonal prismatic coordination sphere, which is bound to six sulfide ligands. The sulfur centre is connected to three tungsten centres, which are pyramidal. The trigonal prisms are layered, sandwiching tungsten atoms between layers of sulfur atoms.1
Depiction of WS2 Crystal Structure1
WS2 in its monolayer form has recently been under particular recognition for its intriguing electrical and optical properties. Bulk WS2 is generally an n-type semiconductor with an indirect bandgap (~1.4 eV). On the other hand, monolayer WS2 has a direct bandgap of ~1.9 eV, and can be useful in low-power switching devices.
WS2 Raman Spectrum
Preparation Method: Solution-Based Exfoliation
Thin Semiconducting Films
We can do custom formulations, and fill orders for large volumes of the solution! Contact us for more details.
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These materials have been used in publications, including:
Electronics and optoelectronics of two-dimensional transition metal dicalcogenides, Wang et al. Nature Nanotechnology, 7 (2012), pp. 699-712
Extraordinary room-temperature photoluminescence in WS2 monolayers, Gutierrez et al. arXiv:1208.1325 [cond-mat.mes-hall]
Quantitative Determination of the Band Gap of WS2 with Ambipolar Ionic Liquid-Gated Transistors, Braga et al. Nano Letters, 12 (2012). pp. 5218-5223
1Adapted from the Wikimedia Commons file Molybdenite-3D-balls.png