Synthesis and Characterization of Visible-Active Molybdenum Disulfide (2H-MoS2) Nanospheres

In current study, a novel 2H-MoS2 nanospheres were successfully synthesized and underwent structural-as well as optical-property characterizations. The MoS2 were prepared by one pot hydrothermal approach through adopting L-cysteine as environmentally-benign chalcogenide precursor. TEM image shows that the as-synthesized MoS2 appear to be spherical in shape with size distribution in the range of 120 nm - 180 nm. HRTEM lattice-fringes imaging further elucidate that the interlayer spacing at the edges is equal to be 0.62 nm that correspond to (002) plane stacking. Also, the HRTEM image clearly-illustrate that the internal microstructure of MoS2 composed of randomly-arrayed alternating layers, which render the postulation that the formation of nanosphere is driven by self-assembly of individual layers into globular morphology. XRD diffractogram that appear to be broad and unresolved reveal the partially crystalline nature of the sample. Optical-absorption spectra depicts the sample is visible active with featureless absorption, which can attribute to indirect transition of the excitions generated. By using Tauc plot, the bandgap energy is determined to be 1.75 eV, which reflect the nanospheres are indeed visible-active nanostructures.