Synthesis, Self-assembly And Properties Research Of Several Inorganic Functional Nanomaterials

Manipulated synthesis of inorganic nanostructures with different morphology and exploring their distinctive properties are the hot areas in nanoscience and nanotechnology. Self-assembly of nanomaterials into special functional nanoatructures attracts much scientific attention, and also the base to make application for actual production .The main results are summarized as the following: 1. Ordering of disordered nanowires: Spontaneous formation of highly aligned, ultralong Ag nanowire films at oil–water–air interfaceOne-dimensional nanomaterials and their assemblies attract considerable scientific interest in the physical, chemical, and biological fields because of their potential applications in electronic and optical devices. The interface assembly method has become an important route for the self-assembly of nanoparticles, nanosheets, nanotubes, and nanorods, but the self-assembly of ultralong nanowires has only been successful using the Langmuir–Blodgett approach. A novel approach for the spontaneous formation of highly aligned, ultralong Ag nanowire films at the oil-water-air interface is described. In this approach, the three-phase interface directs the movement and self-assembly process of the ultralong Ag nanowires without the effect of an external force or complex apparatus. The ordered films exhibit intrinsic large electromagnetic fields that are localized in the interstitials between adjacent nanowires. This new three-phase-interface approach is proven to be a general route that can be extended to self-assemble other ultralong nanowires and produce ordered films. 2. Synthesis of zinc oxide nanoparticles with strong, tunable and stable visible light emission by solid-state transformation of Zn(II)-organic coordination polymersLigand-free ZnO nanoparticles with a mean diameter of 100 nm were simply synthesized by solid-state transformation of Zn(II)-organic infinite coordination polymer particles (ICPs) at 550 oC. The well-crystallized ZnO nanoparticles exhibit strong visible emission centred at 600 nm and the emission light clearly appeared under UV light, representing the first example of strong, tunable and stable visible photoluminescence from relatively large ZnO nanoparticles both in solution and in the solid state. ZnO nanoparticles synthesized by this approach without any surfactant or capping molecules and their visible emission is generally stable and remains almost unchanged while keeping sample in air at least 3 months. The possible mechanism of strong visible emission was also proposed that oxygen vacancies and surface defects play an important role in the visible emission based on the results of electron paramagnetic resonance (EPR) spectra and decay lifetime curve. ZnO nanoparticles with strong visible emission centred at 500 nm could also be obtained by changing the compositions of coordination polymers. This solid-state transformation method provides a new approach to synthesize stable ZnO nanoparticles with strong and tunable visible emission under a wide range of compositions of coordination polymers. 3. Synthesis of indium oxide nanocrystals with the porous octahedral shape by solid-state transformation of In(III)-organic coordination polymersIndium oxide nanoparticles were synthesized by two steps. First, In(III)-organic coordination polymer particles with octahedral shape prepared, and then the coordination polymer particles transformed to indium oxide crystals with the morphology of porous octahedral by annealing the precursor at 550 oC . Sample was characterized by XRD, SEM, TEM, BET and UV-vis which has shown that the specific surface area is 25 m2 g-1 and the particles with a mean diameter of 15 nm composed the indium oxide nanocrystals with the morphology of porous octahedron. Controlling the morphology of precursor can control the shape and properties of metal oxide. Its potential application should to be further investigated. Key words: self-assembly at interface, metal oxide, nanowires, coordination polymer, optical properties...