Carbon dots mediated room-temperature synthesis of gold nanoparticles in poly(ethylene glycol)

Abstract

We report an efficient room-temperature synthesis of Au nanoparticles (NPs) using carbon dots (C-dots) as mediator in poly(ethylene glycol). The synthesis does not require any irradiation or heating for the reduction of the metal precursor and it yields smaller sized particles of ~15 nm, mostly octahedron in shape. The effect of varying concentrations of the Au precursor and C-dots on the synthesis was studied, which demonstrated the variation in particle size and shape with change in either the precursor or C-dots concentration. Time-resolved absorbance study for the synthesis of Au NPs showed the sigmoidal behavior for the autocatalytic growth having the lagging phase of induction period. The optimum concentration of the precursor and the C-dots were determined for the synthesis of well-dispersed Au NPs. The stability of the prepared Au NPs was also determined, showing that at optimum concentration of the precursor and C-dots, the particles were stable and did not precipitate for several days.