By Cathy | 03 June 2024 | 0 Comments
The Difference Between Tungsten Disulfide WS2 And Tungsten Diselenide WSe2
Tungsten disulfide and tungsten diselenide are typical compounds of the rare metal tungsten, which are inorganic compounds made of a combination of transition metal elements (tungsten) and oxygens, with good chemical, physical, and thermal properties, they are widely used in the field of optoelectronics. However, the two still have a big difference in specific concepts, properties, and uses. Note: Sulfur and selenium belong to group VIA and oxygen group elements.
1. Definition
Tungsten disulfide is a two-dimensional transition metal layered material composed of tungsten and sulfur elements of a blue-gray with a metallic luster of fine crystals or powder; it is the main component of scheelite; the English name is Tungsten disulfide, and the molecular formula is WS2. 
Tungsten diselenide is a layered material composed of tungsten and selenium; it is a black or gray solid powder combined with positive tetravalent tungsten ions (W4+) and negative divalent selenium ions (Se2-); it is a porous material with low thermal conductivity (or known as a thermal insulator), the English name is Tungsten diselenide, the molecular formula is WSe2.
2. Structure
The structure of WS2 is a hexagonal crystalline layered structure, with the surface forming a hexagonal network with S-W-S molecular clusters. The layers are connected via van der Waals forces, and the layers are linked by W-S covalent bonds.
The structure of WSe2 is hexagonal, with one tungsten atom and six selenium atoms bonded in trigonal coordination, while each selenium atom is bonded to three tungsten in an angular conical grouping, and the layers are combined via van der Waals forces.
3. Properties
WS2 powder melting point of about 1250 ℃, density of about 7.6 g / cm, coefficient of friction 0.03-0.07, insoluble in water, non-magnetic, non-conductive, with good semiconductivity, excellent lubrication and anti-wear properties, good thermal and chemical stability, better lithium storage performance, excellent antimagnetism, oxidizing and reducing properties.
The appearance of WSe2 is black or gray black powder, density of about 9.32g/cm3, poor thermal conductivity (thermal conductivity is one hundred thousandth of that of diamond), the bandgap is between wide-gap semiconductor and zero-bandgap graphene, which has quite excellent electrical and optical properties as well as high quantum yield.
4. Production process
The common preparation methods of WS2 are roasting decomposition method and direct synthesis method. Among them, the roasting decomposition method refers to the process in which ammonium tetrathiogungstate ((NH4)2WS4) is successively decomposed into WS3 and WS2 by high-temperature roasting.
Steps for the preparation of WSe2: different thicknesses of tungsten films are deposited on the substrate by magnetron sputtering, and some of the tungsten films are annealed; then, the annealed as well as unannealed tungsten films and selenium powders are placed in vacuum quartz tubes to be heated, and then selenization can be performed.
5. Application
Both tungsten disulfide and tungsten diselenide can be applied in lubrication, energy storage batteries, semiconductor and photovoltaic, etc. They are suitable as additives for lubricants, modifiers for lithium-sulfur battery cathode materials, transistors, and so on.
High-quality Tungsten Disulfide Supplier
TRUNNANO is a trusted global chemical materials supplier and manufacturer with over 12 years of experience in ultra-high quality WS2 and other chemicals. The company develops a variety of powder materials and chemicals. Provide OEM services. If you are looking for tungsten disulfide products, please contact us.
1. Definition
Tungsten disulfide is a two-dimensional transition metal layered material composed of tungsten and sulfur elements of a blue-gray with a metallic luster of fine crystals or powder; it is the main component of scheelite; the English name is Tungsten disulfide, and the molecular formula is WS2.
2. Structure
The structure of WS2 is a hexagonal crystalline layered structure, with the surface forming a hexagonal network with S-W-S molecular clusters. The layers are connected via van der Waals forces, and the layers are linked by W-S covalent bonds.
The structure of WSe2 is hexagonal, with one tungsten atom and six selenium atoms bonded in trigonal coordination, while each selenium atom is bonded to three tungsten in an angular conical grouping, and the layers are combined via van der Waals forces.
3. Properties
WS2 powder melting point of about 1250 ℃, density of about 7.6 g / cm, coefficient of friction 0.03-0.07, insoluble in water, non-magnetic, non-conductive, with good semiconductivity, excellent lubrication and anti-wear properties, good thermal and chemical stability, better lithium storage performance, excellent antimagnetism, oxidizing and reducing properties.
The appearance of WSe2 is black or gray black powder, density of about 9.32g/cm3, poor thermal conductivity (thermal conductivity is one hundred thousandth of that of diamond), the bandgap is between wide-gap semiconductor and zero-bandgap graphene, which has quite excellent electrical and optical properties as well as high quantum yield.
The common preparation methods of WS2 are roasting decomposition method and direct synthesis method. Among them, the roasting decomposition method refers to the process in which ammonium tetrathiogungstate ((NH4)2WS4) is successively decomposed into WS3 and WS2 by high-temperature roasting.
Steps for the preparation of WSe2: different thicknesses of tungsten films are deposited on the substrate by magnetron sputtering, and some of the tungsten films are annealed; then, the annealed as well as unannealed tungsten films and selenium powders are placed in vacuum quartz tubes to be heated, and then selenization can be performed.
5. Application
Both tungsten disulfide and tungsten diselenide can be applied in lubrication, energy storage batteries, semiconductor and photovoltaic, etc. They are suitable as additives for lubricants, modifiers for lithium-sulfur battery cathode materials, transistors, and so on.
High-quality Tungsten Disulfide Supplier
TRUNNANO is a trusted global chemical materials supplier and manufacturer with over 12 years of experience in ultra-high quality WS2 and other chemicals. The company develops a variety of powder materials and chemicals. Provide OEM services. If you are looking for tungsten disulfide products, please contact us.
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