Study of well-aligned Ag@ZnO nanoflower arrays with growth, photoluminescence and ultrafast nonlinear absorption properties

ZnO nanoflowers (NFs) and silver-decorated ZnO (Ag@ZnO) NFs arrays were prepared by two/three-step progress of magnetron sputtering, hydrothermal and magnetron sputtering method, respectively. The effect of silver nanoparticles (NPs) on the visible emission performance of ZnO arrays was described. The results show that the ultraviolet emission (UVE) peak of ZnO NFs array is concentrated at 380 nm red-shifted to longer wavelength after being decorated with Ag NPs in the diameter of 18-50 nm. It is very interesting that the in-tensity of the visible emission (VE) is enhanced by the VE ratio of 1.43 for the Ag@ZnO NFs arrays of 0.03 mol/L. However, for the Ag@ZnO NFs arrays of 0.015 mol/L, the UVE peak blue shift from 387 nm to 384 nm, indi-cating a slight decrease in emission intensity due to the decorating Ag NPs of 10-20 nm. The enhancement of VE is considered as the synergistic effect of competition between the increase of exciton concentration and the enhancement of Ag NPs local field. The Z-scan measurement of the opening was performed at 800 nm, revealing the contribution of metal NPs. Ag@ZnO NFs arrays with remarkable nonlinear optical properties are a potential nanomaterial for the development of multifunctional optoelectronic devices.