Synthesis and Characterization of Nanostructured Semiconductor Materials by Self-assembling Methods
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This thesis reported synthesis of TiO2 nanostructures and Fe2O3 nanostructures and studied on self-assembling process. The morphologies, compositions, and physicochemical properties of the prepared samples were characterized by TEM, FESEM, XRD, FTIR, UV, and SQUID etc. Nanoparticles of transition metal oxides own their special function to become an interesting hot research topic in the recent decades. In particular, superparamagnetic iron oxide nanoparticles can be used as drug delivery agent and new hard disc drive materials. They have wide application in environment industry as well. Titanium dioxide nanoparticles can be applied in photocatalysts, UV protectors and dye sensitive solar cell etc. Their wide industrial applications for advanced technology development motivate scientists to develop simple, economical and novel synthetic methods, and explore their applications, so that the commercialization of the production of the nanomaterials becomes feasible. The objective of this project is to develop an effective, simple and economical technical route for synthesis of nanosized iron oxide and titanium oxide particles/rods/films. The approach and the progress are outlined as follows. Based on extensive literature reading on the project related area, a novel self-assembling technical route for iron oxide nanostructure and architecture was proposed which has been confirmed to be effective. Detailed experimental investigation on the synthesis of nanoparticles/rods, and instrumental characterization of the particle size, structure, and crystallites, etc. via TEM, FESEM, XRD, FTIR, UV, SQUID are conducted. Uniform nanorods of hematite iron oxide and titanium oxide nanospheres, and anatase TiO2 thin film with micropores have been successfully achieved. Some preliminary exploration for applications of the synthesized nanomaterials has also been carried out. Firstly, a novel assembled scheme of iron oxide nanostructure and architecture by selfassembling process was investigated. The sol-gel technical route was employed to synthesize nearly uniform nanorods of hematite particles. Morphologies and physicochemical properties of iron oxide nanostructure were characterized by analytical instrument. Secondly, titanium oxide nanospheres were synthesized via a hydrothermal process using titanium isopropoxide as the precursor. Titanium oxide nanospheres with inner nanospace andhighly organized crystallites in the shell structure and surface regions were synthesized. It demonstrated that the technical route developed in this work has a high versatility for structural engineering of various targeted morphological products. Thirdly, a simple process of preparing anatase TiO2 thin film with micropores was pursued. The synthesized nano thin film with micropores was used for the material of dye-sensitive solar cell; and effective electron transfer of titanium oxide electrode was confirmed by electrochemical voltammetry. Preparation of the titanium oxide electrode and its electrochemical analysis was studied. The application of the titanium oxide of microporous thin film material as a promoter for electrochemistry voltammetry measuring system was explored in this thesis. In conclusion, the iron oxide nanorods with superparamagnetic property were successfully synthesized by a simple method with low cost materials. Titanium oxide hollow nanospheres were achieved by the assistance of copolymer template. Titanium oxide thin film with microporous structure with significantly high efficiency in electron transfer was realized. Further researches on the synthesis of hybrid iron oxide and titanium oxide nanoparticles, their crystal growth architecture and mechanism, as well as exploration of their applications are recommended.