Plant extract mediated liquid phase exfoliation of MoS2: a sustainable approach to micro and nanostructured material preparation

Molybdenum disulfide (MoS 2 ), a two-dimensional transition metal dichalcogenide with distinctive layer-dependent optical, electrical, and catalytic properties, has attracted significant attention for applications ranging from flexible electronics to energy storage and biosensing. However, conventional synthesis and exfoliation methods for MoS 2 often rely on harsh chemicals, high energy input, and generate toxic derivatives, posing significant health and ecological concerns. Addressing these limitations, this study presents an eco-friendly alternative - the green synthesis of plant extract-mediated MoS 2 micro- and nanostructures using Cissus quadrangularis (CQ), Ocimum sanctum (OS), and Lawsonia inermis (LI) as natural exfoliating and stabilizing agents. Characterization techniques, including X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV-Visible spectroscopy, dynamic light scattering, SEM, and conductivity studies, validated the successful synthesis of MoS 2 materials with distinct morphological, optical, and electrical properties. XRD confirmed the hexagonal phase of MoS 2 , with peak broadening observed in plant-mediated samples consistent with reduced crystallite size and/or lattice strain. Raman spectroscopy and FTIR results revealed the presence of functional groups and spectral features consistent with few-layer character. Dynamic light scattering and UV-Visible spectroscopy studies revealed changes in hydrodynamic size and band structure based on the synthesis route. SEM images showed structural variances ranging from stacked layers to flower-like assemblies, while EDX confirmed the presence of Mo and S in all samples. Electrical measurements suggested semiconducting behaviour in all samples, with conductivity modulated by synthesis conditions. The plant-mediated exfoliation method presents a viable, eco-friendly alternative to conventional approaches, with potential relevance to flexible electronics and catalysis; the solvent-exfoliated control (MoS 2 –NMP) showed higher conductivity than the plant-mediated samples, an important finding for optimizing electrical performance in future device-oriented studies.