Researches On Spectroscopic Properties Of Several Hybrid Silica Microspheres

Nano-scale materials with special structures possess a potential of wide applications in many scientific domains for their various unique physical and chemical properties attributing to controllable structures. Therefore, this area has been one of the hottest spot of all the scientific fields, attracting the researching focus of countless scientists. Among all the nano-materials, silica microspheres take an important position for its easy synthesis, stable property and excellent bio-integration. This paper focused on the fabrications and researches on the optical properties of silica microspheres, complex silica-metal core-shell structures and artificial photonic crystals.The experimental foundation of this paper is the synthesis of highly monodispersed, narrow diameter distribution and complete sphere-shaped silica microsphere particles. Based on a traditional St(o|¨)ber method, we have developed a step-by-step method to fabricate silica microspheres. First we synthesized silica microspheres with relatively small diameter as seeds. Then, we use these seeds to make further reaction. By varying the proportion of the reacting reagent, we can obtain silica microspheres with desired size. The diameter of the silica microspheres developed using this method can be tuned from 200nm to 500nm. Once the step-by-step reaction is over, the size of the spheres is established. No other reactions are necessary.Due to the surface Plasmon resonance effect, metal nanoparticles and nano-scale structures possess special optical properties. Thus, they have extremely researching values, developing potentials and applicable future in many scientific fields. In this paper, we developed a convenient step-by-step method to fabricate silica microspheres incorporated with gold crystals, which can be written as Au@SiO₂. After using APTES to functionalize the silica microspheres, we can incorporate gold crystals into the surface of the microspheres via the mutual reaction between the amino functional groups and the gold anions, which producing the gold seeds. Then, we repeated the decorating reactions on the gold seeds to obtain silica microspheres with contiguous and uniform gold shells.Opal is a natural material with photonic bandgap. Researchers imitated structures of the Opal to make photonic crystals via molecular self-assembling methods. This paper focused on the procedure of developing photonic crystals by using self-assembling of silica microspheres and introduced spectrum measurement and theoretical analysis on the samples.The silica artificial opal incorporated with silver nanoparticles was fabricated by the electroplating technique. The optical microscope images of the synthetic sample and the corresponding optical properties were measured after each treatment of electroplating-washing-drying circle. The transmission and the reflection spectra presented a red shift. Combining the SEM images, it was seen that the silver nanoparticles could be directly deposited on the surface of silica spheres in the opaline structure. The silver/silica complex opal film could provide a simple way to tune the opal properties by controlling silver nanoparticles in the silica opal.