Fig. 3. (a) FTIR spectra and (b) 1H NMR spectra of PbTe NPs before and after ligand exchange; (c) UV-vis spectra of CdSe NPs before and after ligand exchange. The first exciton peak of the NPs is preserved, while the GQD absorption feature near 287 nm is additionally observed. This indicates that the NP core structures are preserved during ligand exchange. (d) Size distribution of PbS NPs before (red) and after (blue) GQD ligand exchange; the inset shows the ζ-potential after GQD ligand exchange.
