Fig. 2. TEM images of Pb-based NPs before (a and c) and after (b and d) GQD ligand exchange. (a and b) PbTe, 30 nm; (c and d) PbSe, 10 nm. The scale bars are 50 nm. Insets are photos of NPs dispersed in the (top) non-polar phase, toluene, and (bottom) the polar phase, formamide, with GQDs.