Investigation of structural and luminescence properties of nanocrystalline tungsten-incorporated molybdenum disulphide ternary compounds: an experimental and DFT study

Abstract

The present manuscript reports the synthesis of tungsten-incorporated molybdenum disulphide ternary compounds in particle form at the nanoscale using existing solid state reactions, followed by ultrasonication and a density functional theory (DFT) investigation of the compound system. The effect of W in the W-inserted MoS 2 ternary compound system is the subject of current research. A comparative study shows enhanced photoluminescence (PL) at room temperature in the as-synthesized transition metal dichalcogenide (TMD) ternary compound. The compositional and structural characterization studies of the materials are performed using XRD, SEM, EDX, TEM and Raman spectroscopy. We have observed that a combination of W and S leads to better crystallinity than the combination of Mo and S in the compound system. The high band gap (BG) energy also confirms the nanoscale dimension of the material system which may be attributed to the formation of excitonic states from spin splitting and band nesting effects. A theoretical investigation of the effect of W in the MoS 2 system using DFT also reveals that insertion of W leads the system toward a direct BG semiconductor (SC). Multiple BGs of the material in the visible light range as found by UV-Visible (UV-Vis) spectroscopy, suggest applicability of these materials in luminescence devices and photocatalytic activity.

Synthesis of ZnFe2O4@MoS2 core-shell nanocomposites with enhanced lubrication performance as lubricant additives

“…This proves the existence of the highly crystalline cubic obelisk structure ZnFe 2 O 4 [28]. At the same time, the XRD pattern of MoS 2 also conforms to the standard pattern (JCPDS 37–1492) (Kalita et al , 2019). In addition, the main diffraction peaks of ZnFe 2 O 4 and MoS 2 appear in ZnFe 2 O 4 @MoS 2 nanocomposites, and the ZnFe 2 O 4 @MoS 2 core–shell composite particles with different shell thicknesses also show similar XRD patterns.…”