Time-dependent hydrothermal synthesis of carbon dots for agricultural applications

Carbon dots (CDs) have gained attention as promising fluorescent materials owing to their low toxicity, high biocompatibility, excellent aqueous solubility, and outstanding optoelectronic properties. Their average size can be precisely tuned by varying precursor concentrations, processing temperatures, and reaction time. In this study, Myxopyrum smilacifolium leaves were used as carbon precursor to synthesize water-soluble CDs via a one-pot hydrothermal technique. The synthesis conditions were systematically altered to investigate the effect of reaction time on the optical and structural properties of the CDs. The synthesized CDs were analyzed by UV-Visible absorption spectroscopy, photoluminescence spectroscopy, Fourier Transform Infrared (FTIR) Spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). With increasing reaction time, the photoluminescence emission exhibited a blue shift, attributed to changes in the morphological and optical properties of the CDs. The DLS analysis offers insights into the variation in the size distribution of CDs subject to various synthesis conditions. FT-IR analysis shown the presence of hydroxyl and amine functional groups on the surface of the CDs. The impact of the synthesized CDs on mung bean seed germination and seedling development was investigated, demonstrating a significant improvement in germination rates and seedling development. These findings highlights the potential of hydrothermally synthesized CDs as sustainable nanomaterials with promising applications in agricultural biotechnology. • CDs synthesized via green synthesis from Myxopyrum smilacifolium leaf extract. • Studied the effect of preparation time on the physicochemical properties of the CDs. • Optical, surface, and size traits confirmed through various characterizations. • CDs enhanced seed germination and plant growth of mung bean notably. • This study validates the use of plant-derived CDs as sustainable agricultural tools.