Carbon Dots: An Insight into Their Application in Heavy Metal Sensing

Abstract

The design of nanomaterials for application in diverse fields ranging from photovoltaic to fluorescence sensing is a research area of increasing interest. Recently, Quantum Dots (QDs), which are classified as semiconductor quantum dots (SQDs) and Carbon dots (CDs), have become a hot topic of investigation, owing to their extraordinary tunable fluorescence emission properties that render them excellent candidates for sensing metal ions. The detection of metal ions in aqueous solutions with high sensitivity is very important as these ions have toxicological and environmental impacts. In this short review, we have described the fluorescence emission properties of CDs and their application for the detection of different metal ions, such as Hg2+, Pb2+, Cu2+, Fe3+, Cd2+, and Cr6+.

Design of Fluorescent Carbon Dots (CDs) for the Selective detection of Metal‐Containing Ions

“…In this review, we focus on the sensing capacity of CDs that is primarily based on the quenching of their fluorescence, that is mainly based both on (i) analyte-induced quenching or (ii) the improved fluorescence of a CDquencher complex; this second mechanism happens via an electron transfer or an energy transfer with an electronwithdrawing or acceptor analyte. [39][40][41][42] The interaction and further binding of CD with analytes of interest occurs only if the surface of CDs possesses particular functional groups able to form a coordination complex with a specific heavy metal. There are multiple strategies to provide CDs with adequate chelating groups at their surface, with include the use of specific precursors, post-functionalization and the modification with additional molecules with quenching or fluorophore properties.…”