Nanomaterials Synthesis and Characterization by Liquid Phase Exfoliation and Vapor Liquid Solid Methods

In this work, Liquid phase exfoliation (LPE) of Black Phosphorous (BP) atomic layers down to monolayer and also Sulfur assisted Vapor Liquid Solid (VLS) - chemical vapor deposition (CVD) of Silica nanowires are proposed and investigated. In chapter 2, using compatible solvent and suitable ultrasonic energy and time, BP nanosheets have been synthesized. The process considering solvent, exfoliation and centrifugation time has been optimized. Optical microscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Raman spectroscopy, photoluminescence measurement (PL), UV-Vis- near IR spectroscopy and Dynamic Light Scattering (DLS) have been used to study the properties and characteristics of the produced sheets. The nanosheets have been used as films for humidity detection sensors and also as reinforcing material in nanocomposite polymers. Sodium transfer pathway in the synthesized nanoflakes has also been investigated using in-situ TEM. Specifically in chapter 3, Sulfur assisted Vapor Liquid Solid (VLS) technique has been employed for the synthesis of SiOx nanowires in the presence of Sulfur (S) promoter gas. The process considering growth time and temperature, seeding concentration, and sulfur have been studied. In this study, different characterization methods such as SEM, TEM, AFM and EDS have been performed for analyzing the grown structures and optimizing the growth process.