Synthesis Nano/Micrometer Functional Materials With Regular Structure By Electrodeposition

Recent years, synthesis of materials with complex structures has attracted great attention because many those materials have unique optical, magnetic and mechanical properties. With the development of biotechnology, the bio-inspired synthesis crystals with complex forms that mimic natural biominerals has become a hot area of research. The biomineralization process normally requires biomaterials, such as, polymer, protein, polypeptide or amino acid as soft templet.Electrodeposition is an electrochemical deposition method to prepare polycrystal thin films and nanostructures in aqueous or nonaqueous solutions. There are sevral advantages about electrodeposition. Electrodeposition normally is performed under room temperature or a little above room temperature so that it is suitable for preparing nano/microstructures. The amount of deposition can be controlled by Faraday law. The rate of deposition can be controlled by over-potential. The larger over-potential is applied, the faster growth rate can be obtained. Moreover, electrodeposition is a low cost and easy scale-up deposition method.Calcium carbonate (CaCO₃), one of the most abundant biominerals, exists widely in sea shells, coral, coccoliths, and exoskeletons. Calcium carbonate was widely used in industry, such as, paper, rubber, plastic and paint. In this thesis, the hybrid L-Ala-CaCO₃ with unique pancake lamellar structures which is similar to the sea shells with layered hybrid inorganic-organic structures have been obtained through electrodeposition method using L-α-Alanine (L-Ala) as the soft template at room temperature (about 25℃) in Ca(NO₃)₂-H₂O₂ aqueous solutions. The combination of electrochemical method and biomineralization concept may supply a novel and facile method to synthesize functional materials which mimic the unique structures of nature biominerals.ZnO is a wide gap semiconductor that has attracted considerable attention recently for various potential applications in low-voltage and short-wavelength optoelectronic devices, such as light emitting diodes and laser diodes. In this thesis, ZnO has been electrodeposited directly from solution at 70℃. The effects of the substrates and different type of amino acids on morphologies and orientations of the electrodeposited ZnO have also been studied. ZnO with different morphologies can be obtained through using different substrates and different amino acids as soft templet.Indium oxide (In₂O₃), a n-type semiconductor with a wide band gap of about 3.6 eV, has been widely used for optoelectronic devices and other applications, including gas sensors, solar cells, window heater, and flat panel displays. In this thesis, nanocrystalline pillared In(OH)₃ has been electrodeposited from InCl₃-H₂O₂ aqueous solution at 90℃. From the higher SEM picture, it is clearly that, the pillared In(OH)₃ was assembled by nano-pillar with the diameter about 10-20 nm. Nano-In₂O₃ has been obtained by thermal decomposing In(OH)₃ at 300℃. The effects of the different substrates or amino acids on morphologies and orientations of the electrodeposited In(OH)₃ have also been explored. Based on experimental results, the possible formation mechanism has been discussed.