Alfa Chemistry is a technological business that specializes in two-dimensional (2D) nanomaterial research and development, with an emphasis on MXenes and MAX phase materials, black phosphorus, and other materials. Our research and development team is led by a group of PhDs with international experience and years of research. To fulfill the needs of our customers, we can "personalize" unique tungsten disulfide solutions. Contact us today and let us assist you in rapidly resolving your issue.
Tungsten Disulfide (WS2)
The transition metal disulfide (TMD) family of compounds includes tungsten disulfide (WS2). Low coefficient of friction, good chemical stability, and heat stability are just a few of the benefits of WS2. Bulk WS2 is usually an n-type semiconductor with a 1.4 eV indirect band gap. Monolayer WS2 offers an outstanding electrical and optical property set for application in low-power switching devices, with a direct band gap of 1.9 eV.
Tungsten disulfide is commonly utilized in transistors, sensors, photocatalysis, and electronic devices due to its high solubility in water and ethanol.
Fig 1. Anisotropic transport properties of tungsten disulfide. (Pisoni A, et al. 2016)
WS2 Solution Synthesis and Characterization
Alfa Chemistry offers custom solutions containing WS2 flakes. We make WS2 solutions by sonicating high-quality WS2 bulk crystals produced using the gas phase transport (CVT) approach. In a variety of polar solvents, WS2 is easily dispersed. Depending on your needs, we may create monolayer, few-layer, multilayer, or even bulk stacked solutions. Please get in touch with us to figure out which solution you prefer.
Alfa Chemistry uses the following formulations to make the most stable monolayer and multilayer ethanol/water dispersions.
- Obtain the needed amount of material (up to 1 mg/mL) by weighing it.
- Ethanol to deionized water in a 1:1 ratio
- To break up the substance, vigorously shake it.
- To uniformly scatter the material, process for 2 hours in an ultrasonic bath.
Since the WS2 crystals grown by CVT are highly crystalline, ultrasonic treatment of stripped WS2 layers produces highly crystalline WS2 monolayers, a few layers, and some thick layers suspended in solution. The solution contains mainly monolayer flakes, but other thicknesses may be observed.
Custom solutions are stable in the presence of oxygen and can be easily applied as a thin film coating on any substrate or surface. Photoluminescence is formed by flakes deposited on various substrates, depending on the thickness of the layer. The monolayer response dominates the photoluminescence, with a strong peak at 2.05 eV.
Transmission electron microscopy (TEM), electron energy dispersive spectroscopy (EDAX), Raman spectroscopy, and scanning electron microscopy (SEM) have all been used to characterize WS2 nanomaterials.
Reference
- Pisoni A, et al. (2016). "Anisotropic Transport Properties of Tungsten Disulfide." Scripta Materialia. 114: 48-50.
Please kindly note that our products are for research use only.
