Optical properties of silicon dioxide nanotube and decaoctahedren structures

• Main Authors: Chin-Wei Chen, 陳志瑋
• Other Authors: 陳永芳
• Format: Others
• Language: en_US
• Online Access: http://ndltd.ncl.edu.tw/handle/79466121283638491056

碩士 === 國立臺灣大學 === 物理研究所 === 93 === Abstract In this thesis, we reported an investigation of optical properties of novel structures of mesoporous silica materials. The experimental techniques include Photoluminescence (PL), Photoluminescence excitation (PLE), X-ray diffraction, and Fourier transform infrared spectra. Several interesting results have been discovered which are summarized as follows. I. Optical anisotropy of MCM-41 mesoporous silica doped R6G materials For mesoporous silica materials with hierarchical nanotube structure, it is found that the decay behavior of the luminescent intensity follows an exponential function. PLE spectra were used to confirm the origin of the emission. We show that the PL spectra reveal strong polarization dependence due to the anisotropic structure of the sample. The optical anisotropy is attributed to the large difference of the dielectric constant between the cylinder and its surrendering. II. Whispering gallery modes in highly hexagonal Symmetric structures of 3-D SBA-1 mesoporous silica In chapter 4, we show some optical properties of mesoporous silica materials with highly hexagonally 3-D symmetric structure, so called SBA-1, by Fourier Transform Infrared Spectroscopy (FTIR). Based on hexagonal cavity model, we can compare the theoretical and experimental WGM results. In addition, we also show that the absorption strength of CO2 and H2O molecules can be greatly enhanced due to the existence of WGMs in SBA-1 mesoporous structure. When the absorption frequencies of gas molecules match with WGMs, the light wave can be completely absorbed.