One-pot bioinspired synthesis of fluorescent metal chalcogenide and carbon quantum dots: Applications and potential biotoxicity.

Quantum dots (QDs) are promising nanoscale materials with sizes ranging from 1 to 10 nm, and have exponentially triggered scientific interest worldwide during the past decade. They exhibit size-tunable optical features, zero-dimensional structures, and quantum confinement effects. Moreover, they can be tailored to suit various applications. Phyto-synthesis of fluorescent metal chalcogenide QDs and carbon dots (CDs) is a green, feasible, low-cost, and environmentally safe approach to overcome the limitations of chemical and physical synthesis techniques. Different plant extracts provide several phytochemical constituents with numerous functional moieties for natural capping and stabilization of the synthesized metal chalcogenide QDs and CDs. Therefore, the green synthesis of metal chalcogenide QDs and CDs, their optical and structural properties, and applications such as diagnostics, biosensing, heavy metal detection, and photocatalytic degradation are comprehensively summarized in this review. Furthermore, the biovalorization of agricultural wastes, such as fruit and vegetable peels, is addressed to produce high-value metal chalcogenide QDs and CDs. In addition, the toxicity issues associated with these particles are described for the safe usage of QDs. Challenges that restrict the widespread application of QD particles are discussed along with future perspectives for their commercial, safe, and upscale production.