Monodispersed silver quantum dots (Ag QDs) of sub 5 nm range are prepared through a facile and size-controllable green synthesis route using sweet lime (Citrus limetta) peel (SLP) extract. Powder X-ray diffraction studies confirm the formation of face-centered-cubic structured Ag QDs which is corroborated by selected area electron diffraction. The Ag QDs show an absorption maximum at ~415 nm due to characteristic surface plasmon resonance. The Ag QDs prepared at 80 °C exhibit high photoluminescence quenching, indicating low recombination rate and high lifetime of photoexcited electrons. The examination of SLP extract by Fourier-transform infrared spectroscopy, LC-MS and NMR spectroscopy reveals the presence of citrate and carbohydrate biomolecules that could be responsible for the formation of small and stable Ag QDs. The cytotoxic studies indicate that the synthesized Ag QDs are able to effect 71% cancer cells death at 100 µg/mL concentration. Moreover, Ag QDs exhibit minimum inhibitory concentration (MIC) value of 50 μg/mL against all the selected pathogenic bacteria. Present findings suggest that Ag QDs obtained by SLP extract mediated green synthesis can be employed as a low-cost and eco-friendly biocidal agent.

通过使用甜酸橙（Citrus limetta）的简便且尺寸可控的绿色合成路线，制备了亚5纳米范围的单分散银量子点（Ag QDs））果皮（SLP）提取物。粉末X射线衍射研究证实了面心立方结构的Ag QD的形成，这可以通过选定区域的电子衍射得到证实。由于具有特征性的表面等离子体共振，Ag QD在〜415 nm处显示最大吸收。在80°C下制备的Ag QD表现出高的光致发光猝灭，表明低重组率和高光激发电子寿命。通过傅立叶变换红外光谱，LC-MS和NMR光谱对SLP提取物的检查揭示了柠檬酸盐和碳水化合物生物分子的存在，这可能是形成小的稳定的Ag QD的原因。细胞毒性研究表明，在100 µg / mL的浓度下，合成的Ag QD能够实现71％的癌细胞死亡。此外，Ag QD对所有选定的病原菌均表现出最低抑菌浓度（MIC）值为50μg/ mL。目前的发现表明，通过SLP提取物介导的绿色合成获得的Ag QD可以用作低成本和生态友好的杀生物剂。