Research On Structural Color Film Of Opal Photonic Crystals

This structural color is caused by the interaction of microstructure and visible light, include interference, scattering and diffraction. What’s more, the color mechanism of photonic crystals is due to this special photonic bang gap.When this photonic bang gap fall into the scope of visible light, specific frequencies of visible light will not continue to spread through the opal photonic crystals, these specific visible light can be reflected by photonic crystals structure. Finally, structural color occurres due to the coherent diffraction on the surface of opal photonic crystals. Structural color materials with advantages of high saturation, high brightness, rainbow effect, polarization effect and never fades, can be used for photoelectric functional material, display anti counterfeiting materials, biological functional materials at present.Submicron Si O2 microspheres were synthesised by st?ber method, then structural color film of SiO2 photonic crystals were prepared by vertical deposition method in this paper. Meanwhile, composite photonic crystals and core-shell structure photonic crystals film were also prepared. The phase composition and microtopography of SiO2 sphere were characterized and analyzed by XRD, FT-IR, SEM; and then band gap property of opal photonic crystals, photocatalytic performance of SiO2@ZnO core-shell microsphere were researched.(1) Different diameters of monodispersed SiO2 microsphere were synthesized in this paper, XRD and FT-IR result shows a kind of amorphous silica were acquired, SEM analysis indicates the diameter of SiO2 microsphere is 200-500 nm, this microsphere have a uniform size distribution and slippy surfaces. What’s more, the diameter of SiO2 microsphere also can be effected by other factors, like ammonia amounts, tetraethoxysilane concentration, reaction temperatures, different reaction time. The relative standard deviation of SiO2 microsphere increased from 6.42% to 2.73%.(2) Structural color film of SiO2 opal photonic crystals was prepared on the surface of glass substrate by vertical deposition method, SEM result shows that face-centred cubic structure was got in the SiO2 photonic crystals. Reflectance spectrums shows the color effect of structural color film, the peak position of reflectance spectrum ranges from 494 nm to 842 nm with the diameter of silica microsphere increase from 229 nm to 464 nm. At the meantime, the color changes from purple to red through the variation of sphere sizes. The bond strength of structural color film enhanced greatly with 500 °C for 2 h.(3) In this SiO2-ZnO and SiO2-ZnS composite photonic crystals film, XRD result shows the existance of ZnO and ZnS nanoparticles, which have dozens of nanometers. SEM result shows these nanoparticles infiltrate to the voids of face-centred cubic structure. Reflectance spectrums shows the color effect of structural color film, the peak position of reflectance spectrum red shifted about 140 nm with the infiltration of ZnO nanoparticles for 8 times. The peak position of reflectance spectrum red shifted about 85 nm with change of relative refractive index, at the meantime, the color varies from green to red.(4) SiO2@ZnO core-shell microsphere were synthesized via wet chemistry method, XRD and SEM results show that ZnO nanoparticles were grew on the surface of this monodispersed core-shell structure, the shell of SiO2@ZnO core-shell microsphere was 10-20 nm. Photonic crystals film of core-shell structure were prepared by ordered self-assembly method, posteriorly, band gap property and catalytic degradation performance were also analysized in this experiment. Photonic band gap of structural color film red shifted nearly 110 nm in this experiment. Photocatalysis experiment results shows that the core-shell microsphere have great effects on methyl orange and rhodamine-B solution.