Enhanced optical response of ZnO nanocolloids prepared by a picosecond laser

The photoluminescence (PL) of silver-decorated zinc oxide (ZnO/Ag) nanocolloids synthesized by picosecond laser ablation in water was studied. Compared to ZnO, a significant enhancement of the broad near-ultraviolet PL luminescence peak is observed in the presence of Ag nanoparticles (NPs), as well as changes in the broad multi-component visible emission feature. The comparative discussion of the chemical and structural analyses suggests that the high electric field in proximity of the Ag NPs gives rise to an enhancement of the ZnO exciton oscillator strength. Optical coupling results in the increase of spontaneous emission rate and internal quantum efficiency of the Ag-decorated ZnO nanostructures. The presented results are helpful for the design of innovative and highly performing LED devices with spatially uniform output.