Liquid-phase Approaches To The Synthesis Of Functional Oxide Nanocrystals

Nowadays, orderly-structured nano-materials have become the research hotspots in the area of nano-materials. Due to their excellent properties and well-crystallized structures, a variety of functional oxide nanocrystals may be utilized as potential building blocks for the self-assembly into inorganic ordered structure materials or devices for electronics of new generations. Therefore, the synthesis and preparation of high quality functional oxide nanocrystals has attracted steady research interests.In this thesis, on the basis of summarizing and decrypting different soft chemistry methods, we analyzed the thermodynamics and dynamics principles of these methods and, then, studied the preparation of ZnO-Fe2O3 oxides,PbTiO3 and (Pb,Zr)TiO3 nanocrystals by solvothermal method, self-combustion, gas-controlled sol-gel. The research covers the following topics:1. PREPARING ZnO-Fe2O3 OXIDES NANOCRYSTALS BYSOLVOTHERMAL METHOD 1) For the first time, we utilized the refined paraffin instead of the expensive 1-octadecene as solvent in solvothermal method to prepare oxide nanocrystals by using N2 gas to prevent paraffin from oxidation; 2) With paraffin as a solvent, we studied the influence of continuous injection of ferric oleate into the solvent heated at the temperatures from 300 to 340℃on the nanocrystals'size and morphology of Fe3O4, which is formed from ferric oleate thermolysis; 3) heating paraffin to 300~340℃for the synthesis of zinc oxide nanocrystals through thermolysis of zinc oleate with ethanol acting as catalytic agent, we studied the reaction conditions of preparing metal-oxide nanocrystals through the thermolysis of metal-oleate complexes with high decomposition temperature; 3) For the first time, we prepared Zn0.5Fe2.5O4 nanocrystals by injecting a mixture of ferric oleate and zinc oleate with ethanol as catalytic agent.2. PREPARING PT/PZT NANOCRYSTALS THROUGHSELF-COMBUSTION METHOD We studied: 1) the influence of several parameters such as the amount of citric acid, pH value and gelling temperature on the...