Mechanism of the enhancement and quenching of ZnO photoluminescence by ZnO-Ag coupling

Abstract

New nanostructural composites consisting of Ag nanoparticles (NPs)-SiO2-ZnO films were fabricated by depositing ZnO films on silica substrates which had already been implanted by Ag ions at different energies and fluences. The photoluminescence (PL) emission of ZnO films from these nanostructural composites can be enhanced or quenched comparing to that of a ZnO film directly deposited on bare silica substrate. The enhancement of the band gap emission is ascribed to the local field enhancement induced by the resonant coupling between the excitons of ZnO and the surface plasmons (SPs) of Ag NPs, while the quenching is due to the electron transfer from ZnO to Ag NPs. Our results can be used to clarify the ambiguity in controlling the light emission enhancement and quenching of a semiconductor coupled with the SPs of metal NPs, which is very important for the design and applications of semiconductor and metal coupling to highly efficient optoelectronic devices, biosensor, etc.

Surface plasmon resonance in nanostructured Ag incorporated ZnS films

“…58 Observed gradual quenching of visible emission in the present work can be related to the metal plasmonic absorption since the ZnS films with higher Ag incorporation have a broad plasmonic absorption peak covering the visible range (450 nm -650 nm). This broad plasmonic absorption results in the absorption of emissions from ZnS nanoparticles by the Ag particles in the higher Ag incorporated ZnS films.…”

Plasmonic enhancement of blue emission from ZnO nanorods grown on the anodic aluminum oxide (AAO) template

“…5, Ref. [20]) these electrons are without difficulty transferred back to the Fermi level of Ag, which is higher than the defect level located at ZnO. Due to the similar energy values between the Fermi level of Ag and the defect level in ZnO, there is another efficient energy transfer from Ag Fermi level to the defect level at the ZnO side, and the DAP emission is enhanced in the case of sample 2 .…”

“…The most important is energy matching between PL emission and surface plasmons generated in metal nanoparticles. The particles size, the separation distance between semiconductor and metal, and the surface roughness of metal are also important [20,21].…”

Surface plasmon enhanced blue–green photoluminescence from carbon-rich amorphous silicon carbide films

“…The measure of the plasmonic response of a metallic nanoparticle or nanostructure commonly used involves its far-field quantities, such as absorption, scattering, and extinction, and its near-field properties, such as the intensity and spatial distribution of its electromagnetic field enhancements [36]. The electromagnetic field enhancement leads to an increased excitation rate and radiative recombination rate of the electron-hole pairs in the light-emitting layer [37]. Since the PL enhancement involves the near-field exciton-plasmon interaction, the WPLEF curves represent the near-field properties of the SPs.…”