Structural and optical properties of complex-morphology materials based on metal nanostructures

Abstract

Starting from an overview of the basic concepts on the correlation between structural and optical parameters of plasmonic nanostructures, this work presents the results of the synthesis processes and structural, optical and electrical characterizations of metal-based complex morphology and composition nano-composite materials (such as Au Dendrites, SiO2 Nanowires-Au Nanoparticles pea-podded composites, glass/textured_FTO/Au NPs multilayer). The aim is to assess the state of the art and, then, show the innovative contributions that can be proposed in this research field. Opportune methodologies, based on self-organization, have been developed for the production of such materials. Several microscopic techniques have been used to analyze the structural properties of the synthesized materials (i.e. RBS, SEM, AFM, TEM, EDX, EELS), and macroscopic measurements have been used to probe their electrical and optical properties. To understand the growth dynamic and the evolution of these complex systems, the correlation between structural and optical parameters has been established, and phenomenological growth models have been drafted. The entire work has been focused on the research of innovative, versatile and low-cost synthesis techniques, suitable to provide a good control on the size, surface density and geometry of the complex nanostructures. Such optimization of the structural parameters is necessary to modulate the metallic nanostructures optical and electrical properties for each specific application. Therefore, the aim of this study is the fabrication of functional nano-scale-size materials, whose properties can be tailored, in a wide range, simply by controlling the structural characteristics. Optimized optical and electrical properties are required to improve the performance of new photovoltaic devices, biosensors, nano-scale optical devices, sensors and SERS active-substrates.