Optical spectroscopic evaluation on the acquisition of optimal sonication temperature for efficient liquid phase exfoliation of molybdenum disulfide

This work investigates how the sonication temperature affects the liquid phase exfoliation of MoS₂ using optical and morphological approach in attempt to acquire an optimal temperature for such process at ambient room conditions. In an ultrasonic bath, exfoliation was carried out at six different temperatures. UV-Vis, FTIR, Raman spectroscopy and SEM characterizations reveal that moderate room temperature range yield excellent results producing well-dispersed flakes with strong excitonic properties with mild oxidation. Higher temperatures cause substantial oxidation, deterioration and restacking while lower temperatures led to insufficient exfoliation and fragmented morphologies because of insufficient cavitation energy. The findings highlight the importance of temperature control in producing high quality nanosheets for scalable applications.