Improved morphology and excitonic emission of 2D MoS2 by incorporating mechanical grinding in the liquid phase exfoliation synthesis process

• Published in: Physica. E, Low-dimensional systems & nanostructures Low-dimensional systems & nanostructures, 2021-04, Vol.128, p.114617, Article 114617
• Main Authors: Singh, Vineeta, Rath, Shyama
• Format: Article
• Language: English
• Subjects: 2D materials; Light emission; Liquid phase exfoliation; MoS2; Raman spectroscopy; TEM
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2020.114617

MoS2 nanosheets are synthesized by incorporating a manual grinding of the bulk powder prior to the sonication in the standard liquid phase exfoliation process. The light emission properties of MoS2 is thereby found to be significantly improved. Transmission electron microscopy shows continuous ultrathin MoS2 nanosheets of larger dimensions in the grinding-assisted synthesis. Raman spectroscopy measurements show that MoS2 is exfoliated down to 3–4 layers by an inclusion of the grinding. UV–visible and photoluminescence spectroscopy were used to analyze the changes in the optical properties. Grinding helps to reduce the influence of the degradation of the NMP solvent on the emission characteristics of the exfoliated material. The strong visible photoluminescence emission due to sonochemical degradation of NMP is suppressed and the excitonic emission due to the A and B excitons relative to NMP emission is significantly enhanced. The results suggest an easy and reliable approach to enhance the optical emission of two-dimensional MoS2 appreciably. [Display omitted] •A manual grinding of the bulk MoS2 powder prior to the sonication in the standard LPE process is used for the formation of atomically thin layers.•TEM analysis shows continuous ultrathin nanosheets in the grinding-assisted sample with a lateral size of nanometers.•Raman spectroscopy shows that MoS2 is exfoliated down to 3–4 layers by inclusion of the manual grinding.•Photoluminescence spectroscopy shows that the A and B excitonic emission is significantly improved relative to NMP emission in the grinding-assisted sample.