Expedient Access to Gold/Quantum-Dot Nanohybrids Mediated by Poly(ethylene Glycol) Ligands of Distinct Macromolecular...

We report a straightforward methodology to access structurally well-defined hybrid assemblies of plasmonic and excitonic nanoparticles (NPs). The developed strategy is based on the incorporation of quantum dots (QDs) coated with zinc-sulfide shells into poly(ethylene glycol) (PEG) brushes at gold NP surfaces, without the necessity of incorporating specialized functional groups to drive the supracolloidal assembly. Based on control experiments involving PEGs with distinct polymeric architecture and Fourier-transform infrared spectroscopy analysis, we attribute the structure formation to attractive interactions between the QD surface and the monomeric repeat unit of the PEG brushes. This combination leads to short interparticle spacings and plasmon/exciton interactions, resulting in photoluminescence (PL) quenching upon assembly. However, using block-copolymers comprising a NP-adjacent spacer block in addition to a NP-remote PEG block, the distance between gold NPs and QDs can be controlled, which in turn affects the PL properties. The versatility of the structure-formation approach is demonstrated by the possibility of applying it to two distinct core/shell QDs (InP/ZnSe/ZnS and CdSe/CdS/ZnS). This offers new perspectives in the quest for efficient nanomaterial fabrication procedures.