Microwave-assisted Green Synthesis of Carbon Dots from Medicinal Plants: Structural, Morphological, and Optical Insights
J. Environ. Nanotechnol., Volume 14, No 4 (December 2025) pp. 92-99
Abstract
In this study, green carbon dots (GCDs) were synthesized via a microwave-assisted route using three medicinal plants, Bacopa monnieri, Datura metel, and Phyllanthus niruri, as natural carbon precursors. The approach offers an eco-friendly, rapid, and reproducible alternative to conventional synthesis routes. The optical, structural, and morphological characteristics of the GCDs were systematically investigated using UV–Vis spectroscopy, FT-IR, XRD, FE-SEM, and EDAX analyses. The UV–Vis spectra revealed strong π–π* and n–π* transitions, confirming the presence of conjugated carbon networks and surface oxygen functionalities. FT-IR spectra confirmed hydroxyl, carbonyl, and carboxyl groups, imparting hydrophilicity and stability. XRD analysis indicated amorphous graphitic structures with variable degrees of graphitization among the samples. FE-SEM micrographs demonstrated distinct morphologies: Bacopa monnieri-derived GCDs were uniformly spherical; Datura metel-based GCDs exhibited irregular flake-like structures; and Phyllanthus niruri-derived GCDs formed densely packed, porous aggregates. EDX spectra confirmed carbon–oxygen dominance with trace mineral elements unique to each precursor. The comparative analysis reveals that phytochemical composition and precursor nature significantly influence the surface chemistry and optical response of the GCDs. The resulting materials show promise for diverse applications in bioimaging, catalysis, environmental remediation, and drug delivery. This work highlights the potential of medicinal plant-derived precursors as sustainable feedstocks for producing high-quality carbon nanomaterials through a green, energy-efficient synthesis route.
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