Preparation Of 3D NiO-SiO₂ Photonic Crystals By Self-assembled Method

Photonic crystals(PC) are 3D structures with a dielectric constant that varies largely and periodically with lattice spacing comparable to the wavelength of light.This creates a periodically varying scattering potential for the light,giving the material optical properties similar to the electrical properties of a semi-conductors.According to its spatial periodicity,PC can be sorted into 1-D PC,2-D PC and 3-D PC.A range of forbidden frequencies called photonic band gap. Photons with energies lying in the bandgap cannot propagate through the medium.Because of it, PC has some more novel characters than common optical material,such as super-dispersive,the inhibition of spontaneous emission and so on.PC has attracted many scientists from the region of theoretical physics,optical and material science since it was first defined.Presently,the fabrication of photonic crystals,especially those in visible or near-infrared region, is the key to the development of photonic crystals.And the most effective way to fabricate photonic crystals with visible or near-infrared band gap is the self-assembly approach,namely, assembly of the colloidal crystals by monodisperse and sub-micrometer colloidal spheres.In this article,We firstly introduced the latest developments in the fabrication of Photonic Crystals at home and abroad,at the same time do a brief summary in the characters and applications of the Photonic Crystals.Then,we studied the fabrication and the characters of the sphericial particles of mono-dispersed SiO₂,and the opal structural PC.Main results are followed:â… ) We succeeded in fabricated the SiO₂ Photonic Crystals by self-assembled method.â…¡) We attempted to fill the NiO with the high refractive index into the 3D photonic Crystals which is compose of the sphericial particles of mono-dispersed SiO₂.3D NiO-SiO₂ Photonic Crystals were obtained.The Photonic Crystals were characterized by X-ray diffraction,scanning electron microscopy,and UV-VIS spectroscopy.Results show that NiO is homogeneously distributed inside the silica matrix,and maintain the original crystal lattice period.Compared to photonic crystal SiO₂ with same crystal lattice period,the peak wavelength of reflectance spectrum of the photonic crystals SiO₂ suffers a red shift under NiO filling.