Assessing the Optical Properties of 2D MoS2 Nanosheets Synthesized Using Facile Two-Step Sequential Process

Among 2D Transition Metal Dichalcogenides (TMDs), ultrathin molybdenum disulfide (MoS2) nanosheets are well researched in terms of synthesis, characterization and applications owing to its unique properties in contrast to the bulk material. Here, 2D MoS2 suspensions are prepared via grinding-assisted liquid phase exfoliation. The processing parameters like initial concentration of MoS2 powder, grinding hours, solvent and high-power sonication are optimized for efficient and scalable production of MoS2 nanosheets. The suspensions are characterized for their optical and structural properties and are compared to analyze the effect of synthesis conditions on the properties of the obtained samples. The bandgap of the synthesized MoS2 lies above 2.0 eV in contrast with a bandgap of 1.57 eV for bulk sample. The difference between the peaks corresponding to in-plane and out-of-plane vibration modes is lower than bulk sample depicting the formation of mono to few-layered MoS2. It is found that grinding-assisted sonication in NMP solvent is the most efficient method to produce low-dimensional nanosheets. The well dispersed MoS2 nanoflakes can be blended with other nanomaterials to prepare hybrid dispersions and can thus be explored for optoelectronic applications.

Automated summary

Ultrathin molybdenum disulfide (MoS2) nanosheets were successfully prepared via grinding-assisted liquid phase exfoliation. The processing parameters were optimized for efficient and scalable production of MoS2 nanosheets. The synthesized MoS2 exhibited a bandgap above 2.0 eV and a lower difference between in-plane and out-of-plane vibration modes compared to the bulk sample. Grinding-assisted sonication in NMP solvent was found to be the most efficient method for producing low-dimensional nanosheets. The well dispersed MoS2 nanoflakes can be blended with other nanomaterials for optoelectronic applications.