Study On The Solution-Based Chemical Synthesis, Growth Mechanism And Physical Properties Of Inorganic Nanomaterials

In this dissertation, solution-based chemical routes were developed to synthesize inorganic nanomaterials; through investigating experimental process, some proper models are referred to discuss growth mechanism of as-prepared nanomaterials; as-prepared nanomaterials are applied in different fields to check their performance, and it is expected that nanomaterials possess some novel physical properties. The main points are summarized as follows:1. Solvothermal/hydrothermal methods with the help of quasi- (soft template) are developed to controllably synthesize nanomaterials with various morphologies. Fe₃O₄ nanoflakes and nanofractals have been controllably synthesized through solvothermal route under PEG-20000 assistance. The roles of surfactant PEG-20000 and N₂H₄ have been discussed in detail. One key fact has been found that the ferrocene concentrations have vital effect on the morphologies of the products. The sidebranching process and the oscillation of the concentration have been proposed to illustrate the formation mechanisms of the fractal nanocrystals. And diffusion-limited aggregation and nucleation-limited aggregation models have also described the process of fractals growth. Searching a proper model to discuss their growth mechanism, it is significant to find a general route to synthesize the nanomaterials we expect. Furthermore, the PbTe hollow nanospheres and single-crystalline nanotubes have been prepared using an ether-glycerol microemulsion system and an ethanol-glycerol homogeneous system as quasi- (soft template), respectively. This kind of solvothermal/hydrothermal route under quasi soft-template assistance is expected to controllably synthesize the nanomaterials with various morphologies.2. Through searching proper starting materials and reactions, solvothermal route is introduced to prepare functional nanomaterials (such as Si₃N₄, SiC) at lower temperature. Single-crystalline alpha silicon nitride nanowires have been achieved with large scale by the reaction of Mg₃N₂ and SiCl₄ at 600℃. As-obtained nanowires exhibit the quantum size effect in optical properties, showing the red...