Growth and Stabilization of Silver Nanoparticles on
Carbon Dots and Sensing Application
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Abstract
Carbon dots (C-dots) have been proven
to show the capability for
direct reduction of Ag<sup>+</sup> to elemental silver (Ag<sup>0</sup>) without additional reducing agent or external photoirradiation
by incubating Ag<sup>+</sup> with C-dots for 5 min in a water bath
at 50 °C. Silver nanoparticles (Ag-NPs) are simultaneously formed
with an average size of 3.1 ± 1.5 nm and grew on carbon dots.
This process involves the oxidation of amine or phenol hydroxyl groups
on the aromatic ring of C-dots. Meanwhile C-dots protect and stabilize
the Ag-NPs from aggregation in aqueous medium; that is, the Ag-NPs
are stable at least for 45 days in aqueous medium. The formed Ag-NPs
cause significant resonance light scattering (RLS), which correlates
closely with the concentration of silver cation, and this facilitates
quantitative detection of silver in aqueous medium