Fig. 2. Characterizations of the electric charge and fluorescence properties of the synthesized SiO2@PEI-QDs. (a) Zeta potentials and (b) statistical analysis of the zeta potentials of the as-obtained nanocomposites at different stages of their synthesis. (c) Photographs of SiO2, SiO2@PEI, and SiO2@PEI-QDs suspensions under visible (i) and UV light (ii). (d) Fluorescence emission spectra of these particles in deionized water.
