What Are the Effects of Non-Metallic Doping on Tungsten Disulfide Performance?

Non-metal doping of tungsten disulfide (WS₂) involves introducing non-metal atoms into the WS₂ crystal lattice to modify its physical and chemical properties. What are the effects of non-metallic doping on tungsten disulfide performance?

For example, nitrogen doping may occur by occupying interstitial sites within the WS₂ lattice or substituting some sulfur atoms, leading to slight changes in lattice parameters. These changes can enhance the stability of the layered structure of WS₂, suppressing interlayer sliding and thereby improving the overall stability of the material.

Research indicates that appropriate non-metal doping can enhance the thermal stability of tungsten disulfide. For instance, boron (B)-doped WS₂ maintains a robust crystal structure at high temperatures, showing greater resistance to structural transformation or decomposition during thermal annealing compared to undoped WS₂. This makes it viable for applications in high-temperature environments.

Non-metal doping can effectively tune the carrier concentration of tungsten disulfide. Taking phosphorus (P) doping as an example, the distinct outer electron structure of P atoms compared to S atoms introduces additional charge carriers into the band structure of WS₂, altering its electrical properties. By controlling the doping concentration, WS₂ can transition from a semiconductor to a semi-metallic state, making it adaptable for various electronic device applications.

Certain non-metal dopants can significantly improve the electrical conductivity of tungsten disulfide. For instance, carbon (C)-doped WS₂ benefits from the unique electron cloud structure of C atoms, which forms conductive pathways within the WS₂ lattice, facilitating electron transport and enhancing the material’s conductivity. This property positions non-metal-doped WS₂ as a promising candidate for applications in electrode materials and electron transport layers.

Non-metal doping can also modify the optical absorption properties of tungsten disulfide. For example, fluorine (F)-doped WS₂ exhibits significantly enhanced light absorption in the visible and near-infrared regions. This enhancement arises from lattice distortions and changes in the electronic structure induced by doping, which increase the material’s photon absorption cross-section and improve its light absorption efficiency. Such characteristics make non-metal-doped WS₂ highly promising for optoelectronic devices, such as photodetectors and solar cells.

Certain non-metal dopants can also enhance the luminescence properties of tungsten disulfide. For instance, indium (In)-doped WS₂ demonstrates stronger photoluminescence at room temperature, with the emission peak position and intensity adjustable by varying the doping concentration. This opens up new possibilities for WS₂ applications in light-emitting diodes, bioimaging, and related fields.

Non-metal doping can introduce additional active sites on the surface of tungsten disulfide. Taking nitrogen doping as an example, the incorporation of N atoms alters the electron cloud distribution on the WS₂ surface, increasing the reactivity of certain surface atoms. This makes them more effective at adsorbing and activating reaction substrates, thereby accelerating catalytic reaction rates.

By selecting different non-metal dopants, the catalytic selectivity of tungsten disulfide for various reactions can be tailored. For instance, sulfur-doped WS₂ exhibits high selectivity for the hydrogen evolution reaction, while oxygen-doped WS₂ performs better in oxidation reactions. This tunable catalytic selectivity broadens the application prospects of non-metal-doped WS₂ in perse catalytic fields, such as fuel cells and hydrogen production via water splitting.

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