Green synthesis of carbon quantum dots and its composite with Ag/chitosan using citrus fruit extracts

Quantum dots are small semiconductors less than 50 nanometers in size, exhibiting unique optical and electronic properties due to quantum mechanics. Carbon quantum dots (CQDs) are particularly popular due to their size-dependent fluorescence, non-toxicity, biocompatibility, and ease of access. CQDs have significant potential applications in various chemical fields. In this study, CQDs were successfully synthesized using a green, one-step hydrothermal method involving citrus (tangerine). The synthesized CQDs were characterized using UV-VIS, XRD, IR, and TEM methods. The CQDs were then reacted with silver oxide to form CQD/Ag composite, and chitosan polymer was used to synthesize carbon quantum dots/Ag/Chitosan (CQD/Ag/Chit) bio-composite. The product was characterized using ultraviolet and infrared spectroscopy to confirm the bonds. This composite has potential applications in biological fields, as chitosan and silver have strong antibacterial properties, and their combination with active CQDs can enhance these properties.