Surface plasmon-enhanced UV emission of ZnO nanorods using Ag nanoparticles

The emission properties of Ag-decorated ZnO nanorods were studied. The widths and lengths of the nanorods ranged from 60 nm to 200 nm. The photoluminescence (PL) spectra of bare ZnO nanorods showed a weak bandgap emission at around 370 nm and a broad defect-related emission band centred at ∼570 nm. After adding Ag, it resulted in an increase and decrease of the near band edge (NBE) and defect-related emission intensities, respectively. The reasons for the enhancement of the band edge emission which caused by the surface plasmon resonance coupling of the near band edge emission between Ag and ZnO are discussed. The visible emission has been suppressed significantly leading to a UV/visible emission ratio of 6 compared with a value of 1.6 for the pristine ZnO nanorods. The enhancement is due to the surface plasmon resonance effect.