The Influence of Oblique Deposited Angle on Metal Enhanced Fluorescence Property of Ag and Ag/ZnO Core-Shell Structure

Abstract

In this paper, the Ag nanoparticles were successfully prepared by oblique evaporation method, and then the ZnO shell layer was coated on surface of silver particles using wet chemical method. Hereafter, the structure, the morphology and the metal enhanced fluorescence (MEF) property of the Ag and the Ag/ZnO core-shell particles were studied by XRD,SEM,TEM and fluorescence (FL) spectra. From the XRD patterns and the SEM,TEM images, the Ag nanocolumn and the Ag/ZnO composite were successful obtained. Furthermore, the density of Ag nanocolumnar structure decreased with the increase of depositing angle. This phenomenon could be attributed to the surface diffusion function and the shading effect, As the result of the FL spectra, the MEF performance of the Ag/ZnO composite was more prominent than that of Ag nanocolumn, due to the quenching effect. Moreover, the MEF performance of the Ag/ZnO composite depended on the deposited angle, firstly increasing and then decreasing with the tilt angle of Ag/ZnO core-shell structure. The mechanism of fluorescence enhancement would be due to the surface plasmon resonance of Ag surface and the change in photonic mode density and/or reduction in self-quenching of fluorophores for ZnO nanostructure.