Fig. 4. (a) PL of GQDs alone (blue), CdSe NPs alone (red), and GQDs capping CdSe NPs (black), showing dramatically quenched emission for both CdSe NPs and GQDs in the composite. (b) Transient spectroscopy of GQD PL emission. For the two major decay branches, the lifetimes of GQDs alone are τ1 = 1.34 ns and τ2 = 6.77 ns, while the lifetimes of CdSe NPs with GQDs ligands are τ1 = 0.98 ns and τ1 = 6.56 ns.
