Photoluminescence of Two-Dimensional MoS2 Nanosheets Produced by Liquid Exfoliation

Extraordinary properties of two-dimensional materials make them attractive for applications in different fields. One of the prospective niches is optical applications, where such types of materials demonstrate extremely sensitive performance and can be used for labeling. However, the optical properties of liquid-exfoliated 2D materials need to be analyzed. The purpose of this work is to study the absorption and luminescent properties of MoS2 exfoliated in the presence of sodium cholate, which is the most often used surfactant. Ultrasound bath and mixer-assisted exfoliation in water and dimethyl sulfoxide were used. The best quality of MoS2 nanosheets was achieved using shear-assisted liquid-phase exfoliation as a production method and sodium cholate (SC) as a surfactant. The photoluminescent properties of MoS2 nanosheets varied slightly when changing the surfactant concentrations in the range C(SC) = 0.5-2.5 mg/mL. This work is of high practical importance for further enhancement of MoS2 photoluminescent properties via chemical functionalization.

Automated summary

The extraordinary properties of two-dimensional materials make them attractive for various applications, especially in optics. In this study, the absorption and luminescent properties of MoS2 exfoliated in the presence of sodium cholate were investigated. The use of shear-assisted liquid-phase exfoliation and sodium cholate as a surfactant resulted in the highest quality MoS2 nanosheets. The photoluminescent properties of MoS2 nanosheets showed slight variations with changes in surfactant concentrations. This work is of practical importance for improving the photoluminescent properties of MoS2 through chemical functionalization.