Mesoporous silica membranes loaded with Ag or Au nanoparticles and optical nonlinear susceptibilities

Abstract

As a template, mesoporous silica membranes were used to trap Ag or Au nanoparticles into their channels without aggregation, contributing to large third-order nonlinear optical susceptibilities. We compared the susceptibility values of the composite mesoporous membranes synthesized by different electrodeposition methods. Results show that differential pulse amperometry (DPA) electrodeposition method gives rise to larger susceptibilities than that by potentiostatic electrodeposition method. DPA electrodeposition provides buffer time for Ag ions to diffuse to the reaction interface to supply Ag ions concentration, resulting more in-channel Ag nanoparticles. Among the synthesized composite membranes loaded with Ag, samples synthesized by DPA method in lower electrolyte concentration possess the largest susceptibility, which agrees well with results of XRD patterns and HR-TEM images. Similarly, the synthesized composite membranes loaded with Au also show the best susceptibility using this strategy under optimal voltage of −0.2V.