Synthesis Of TiO₂ Thin Films Oriented By Self-assembled Templates

According to the principle of biomimetic systhesis approach, self-assembly andimmobilization of biomolecule(DNA) was studied at the interfaces. Effects of DNAassembled-layers on the deposition of nanocrystalline titanium oxide thin films wereinvestigated at low temperature. Moreover, effects of small molecule of organic silaneon the formation of nano-titanium dioxide film were studied. Nano--titanium dioxidefilms were successfullysynthesized on the functionalized silicon and glass substrates.Firstly, the self-assembled layers of APTMS(3-Aminopropy-trimethoxysilane)were studied at the interfaces with hydroxyl groups. Effects of concentration andreaction time on the self-assembled layers were studied using XPS, contact anglemeasuring instrument, and atomic force microscope. Conformation and stability ofDNA sequences were studied using CD. The optimal conditions were obtained. Onthe other hand, self-assembled layers of phosphated silane molecules were alsostudied at the substrate interface.Titanium dioxide films were suceessfully deposited onto the DNA-immobilizedand phosphated silane-assembled interfaces, characterized using X-photoelectronspectroscopy, X-ray diffraction, Raman spectroscopy and atomic force microscope. Itis indicated that assembled layers of DNA are beneficial to nucleation and growth oftitianium oxide at temperature lower than 50℃, and the phosphated layers caneffectively induce the formation of titanium oxide films at 80℃. These synthesizedtitanium dioxide films show high transmission of visible light, and have potentialapplications in development of transparent conductive films for solar cells andself-cleaning surface, or other functional device.