Fabrication And Optical Properties Of Tantalum Pentoxide Inverse Opal Photonic Crystal

The application of photonic crystals devices has become one of the most important research subjects in all over the world. In this paper, polystyrene (PS) opals template, opal with a closed-packed face centered cubic (fcc) lattice, was prepared using vertical deposition method, centrifugation method, filtering method. Then the precursor of TaCl5/ethanol was infiltrated by sol-gel, the PS opal template was removed by sintered under high temperature. In the end, tantalum pentoxide (Ta2O5) inverse opals photonic crystal with wide photonic band gap was fabricated.Under the scanning microscope it was observed that PS template have relatively perfect orderly dense pile structure, good quality by vertical sedimentary method, when the volume ratio of ethanol/PS (solid content is 5.6%) is 12:1, and temperature of oven is 50℃. Vertical deposition method has high repeatability, can also be operated simply, and the preparation conditions is controlled easily. SEM images also showed that the sample of PS colloidal nanospheres was face-centered-cubic (FCC) structure with its (111) planes parallel to the substrate. For inverse opal, under the scanning microscope it was observed that the porous materials possess three-dimensionally ordered structure, so the PS opal template is also very regular, and aperture is about 310nm, the same as the PS grain diameter. Through the composition analysis (EDS), crystal structure analysis (XRD), thermogravimetric analysis (TG), showed crystal water was formed at first, then lossed at high temperature during the preparation, get their crystal structure for orthogonal crystal department Ta2O5 inverse opal photonic crystal in the end.Finally, Translight software based on the transfer matrix method (TMM) was used to simulate photonic band-gap of the three-dimensional FCC photonic crystals. The calculation results show that relative to PS opals template, the band-gap is not broad just redshift happened when Ta2O5 is infiltrated in the void, while Ta2O5 inverse opal structure has wider photonic band gap but blueshift to normal incidence. With the increasing of incident angle, the band gap is blueshift and smaller. The calculation guides the fabrication of photonic crystals. It provides experimental basis for Ta2O5 and other materials inverse opals photonic crystals, and lays a foundation for studying some optical devices, such as photoelectric switches, photovoltaic cells, sensors etc, it also offers ideal templates for preparation pore structure material by the template technology.