以电泳自组装方法制作三维氧化物微球之光子晶体模板
讲座名称：
以电泳自组装方法制作三维氧化物微球之光子晶体模板
讲座时间：
2014-07-11
讲座人：
骆荣富
形式：
校区：
兴庆校区
实践学分：
讲座内容：
报告题目：以电泳自组装方法制作三维氧化物微球之光子晶体模板
报 告 人：骆荣富 台湾逢甲大学
报告时间：2014年7月11日(星期五) 上午10:00-11:00
报告地点：曲江校区西六楼409会议室
报告摘要：
Fabrication of high sphericity, monodispersed microspheres (100~600 nm) of various oxides (SiO2, TiO2, ZnO, In2O3, SnO2) via sol-gel process and polystyrene (PS) microspheres (200~300 nm) via emulsion polymerization is presented. A high colloidal stability suspension was obtained by carefully adjusting the zeta potential of such microspheres and pH of the colloid. The 3-D photonic crystal (PhC) templates of opaline structure on indium-tin oxide (ITO) coated glasses and silicon wafers were easily formed under electrophoretic self-assembly (EPSA) behavior of microspheres under the influence of exerting electrical forces in EPD tank, where different setups of counter-electrode were attempted to establish a non-uniform electrical field. The lattice constant of an ordered opal structure by EPSA can also be tuned by the applied electrical field gradient. Interestingly various self-assembled 3-D structures of silica microspheres in either symmetrical curvilinear profile or triangular ridges can be produced through the proposed EPSA route using specific counter-electrode setups. In addition, the isothermal heating evaporation-induced self-assembly (IHEISA) was investigated as a complementary route to EPSA method. The measured optic properties of such 3-D PhC templates manifest photonic bandgap (PBG) based on our planar-wave expansion (PWE) simulation to verify the existence of real PBG in our tunable nanostructures PhC samples. To acquire pronounced PBG effect for photonic applications in developing LEDs or solar cells of high conversion efficiency, most of PS microsphere templates are currently used due to its material flexibility to avoid defect or void introduction during the drying stage and to easily transform into inverse opal structure (IOS) by infiltrating sol of other oxides with high dielectric constant (e.g. ZnO or TiO2) and filled with metallic nanoparticles (Ni or Cu) by electrochemical deposition and chemical bath deposition (CBD). Formation of gold nanoparticles by chemical reduction method and dispersed Au particles in PhC templates of SiO2 microspheres with various sizes (210~600 nm) via aerodynamic spraying technique were employed. The Au-PhC template was used as target for surface-enhanced Raman scattering (SERS) effect. Such Au-PhC templates would provide a perfect platform to detect SERS effect for R6G dye, even at its very low concentration situation. Furthermore, the fabrication and characterization of novel 3D photonic crystal heterostructure (PhC-HS) using a variety of materials and exceptional embedded cluster or line defects in photonic crystals are currently underway.
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