Hybrid nanostructures of Au nanocrystals and ZnO nanorods: Layer-by-layer assembly and tunable blue-shift band gap emission

A layer-by-layer assembly technique was developed to synthesize the hybrid nanostructures of Au nanocrystals with diameter of about 5 nm and ZnO nanorods via the electrostatic interaction. In comparison with ZnO nanorods, the Au–ZnO hybrid nanostructures exhibited the broadened and red-shifted surface plasmon band, enhanced band gap emission, and suppressed defect emission due to the strong interfacial coupling between Au and ZnO. Moreover, the band gap emission of the Au–ZnO hybrid nanostructures is controllably blue-shifted with decreasing distance between the Au nanocrystals and ZnO nanorods tuned by the amount of the polyelectrolyte layers due to the exciton and plasmon interactions.