准完全带隙的光波段二氧化硅光子晶体材料的制备

光子晶体（photonic crystal)或光带隙材料（hotonic band-gap material)是指具有光子禁带的周期性电介质结构。制造可见光波段的三维全带隙光子晶体是人目标。通过二氧化硅球自组装合成人工欧泊（artificial opal)是获得此种材料的可行方法之一。实验通过改进模具，选择乙醇作沉降介质，用二氧化硅球沉降法制备了有序性较好的人工欧泊，并对二氧化硅球排布进行了显微形貌观测及透射谱测试。分析表明，二氧化硅球排布为类面心立方结构，其带隙为准完全带隙。     

垂直排列法组装胶体晶体的最新进展

光子晶体是一种具有光子带隙的新型功能材料．利用胶体粒子自组装三维光子晶体由于其制备过程比较经济、简单，从而为很多人所关注．目前报道的方法已有多种．其中垂直排列法的简便易行使得其受到了广泛的研究，但另一方面这种方法本身的缺点也限制了它的使用范围．针对这种情况，很多研究机构提出了他们的改进方法．本文简要概述了在这一方面的最新进展，并且在本实验室已能够制备任意单分散、均一尺寸二氧化硅粒子的基础上，采用恒温快速蒸发自组装法得到了高质量的胶体晶体排列．     

等离子体增强化学气相沉积技术制备锗反蛋白石三维光子晶体

采用溶剂蒸发对流自组装法将单分散二氧化硅(SiO2)微球组装形成三维有序胶体晶体模板,以锗烷(GeH4)为先驱体气用等离子增强化学气相沉积法在350℃填充高折射率材料锗.获得了锗反蛋白石光子晶体.通过扫描电镜、X射线衍射仪对锗反蛋白石的形貌、成分、结构进行了表征.结果表明:锗在SiO2微球空隙内填充均匀,得到的锗为多晶态.锗反蛋白石光子晶体为三维有序多孔结构.等离子体增强化学气相沉积的潜在优势在于可实现材料的低温填充,从而以高分子材料为模板进行复型,得到多种结构的三维光子晶体.     

陶瓷基光子晶体的研究进展

采用以陶瓷材料为母体制备光子晶体是光子晶体制备的一个重要研究发展方向.本文介绍了陶瓷基光子晶体的几种主要的制备方法以及光子晶体在微波和红外、可见光频段中的应用.基于功能陶瓷所具有丰富的光/电功能可以制备陶瓷基光子晶体,文中介绍了可调带隙光子晶体和光子晶体中自发辐射方面的一些研究成果.陶瓷基光子晶体由于具有折射率高,功能广泛,制备手段多样等特点,因而具有广泛的应用前景,如用作电场调节的光开关和在显示领域中基于光子晶体各向异性发光特点的具有定向光发射性能的光源.     

单分散胶体颗粒的有序组装及其应用研究进展

本文综述了近1～2年来课题组在单分散胶体微球有序组装及其应用方面的研究进展.其中包括250～1300 nm宽尺寸范围单分散二氧化硅胶体微球的重力沉降自组织;旨在提高光子晶体折射率反差的TiO2/SiO2复合胶体微球的有序组装;硬模板与催化材料一步复合的二元胶体体系颗粒的有序自组装;一种高效的聚苯乙烯胶体颗粒的批量组装技术;低体积分数聚苯乙烯胶体晶体的制备;以及聚苯乙烯胶粒晶体作为可调谐三维非线性光子晶体在高开关对比的光子晶体光开关方面的应用,和作为制备有序大孔材料硬模板在大分子催化方面的应用等.     

组装胶体晶体用单分散二氧化硅颗粒的制备

采用Stober法合成二氧化硅颗粒。通过X射线衍射（XRD）、傅里叶红外光谱（FT-IR）、扫描电子显微镜（SEM）和原子力显微镜（AFM）对其结构和形貌进行分析。结果表明样品为非晶态固体颗粒，平均粒径为463nm，单分散性较高，平均标准偏差小于5％，表面非常平整光滑。通过垂直沉积法在40℃和60％相对湿度下制备出有序性较好的密排结构的二氧化硅胶体晶体膜。在电子显微镜下，观察到这种胶体晶体是面心立方（FCC）密排结构，（111）晶面平行于基底。透射光谱表明，所制备的胶体晶体在（111）方向具有光子晶体的带隙性质。     

沉积条件对SiO2光子晶体表面形貌的影响

自组装制备是一种常用的三维光子晶体制备方法,在制备光子晶体过程中影响薄膜质量的因素较多.本研究对原始的双基片垂直沉积法进行了一定的改进,控制光照强弱、蒸发速度快慢等条件,沉积了不同的SiO2光子晶体薄膜样品.通过与单基片垂直沉积法得到的薄膜样品进行比较,得到了双基片垂直沉积法沉积光子晶体薄膜样品的最优实验条件.     

光子晶体光纤的研究与进展

光子晶体光纤是90年代发展起来的新型光波导材料,具有十分重要的研究和应用价值.本文综述了光子晶体光纤的特征和传输机理、光子晶体光纤的研究类型、制备工艺,并进一步介绍了光子晶体光纤的几个重要用途.     

响应性光子晶体的研究进展

简要介绍了光子晶体的概念及各种制备方法,详细综述了响应性光子晶体的研究进展,包括:1胶体晶体水凝胶阵列;2反蛋白石结构水凝胶;3反蛋白石状光子晶体微球;4微凝胶胶体晶体;5浸润性控制的光子晶体。     

全光法制作三维光子晶体的研究进展

三维光子晶体作为一种新型材料已经得到了广泛的应用。用全光法制备三维光子晶体具有容易实现、成本低廉等优点。本文介绍了用光学方法制备三维光子晶体的几种方法。     

Evaporation-Assisted Formation of Three-Dimensional Photonic Crystals

The process of evaporation-assisted formation of three-dimensional photonic crystals was studied. The photonic crystals were fabricated by stacking uniform-sized silica spheres into regularly arranged structure with solvent evaporation and sedimentation. Effects of important process parameters, including type of solvent (water and ethanol), system temperature (40° and 60°C), and material for sedimentation cell (quartz, polymethyl methacrylate, and Teflon), on structure regularity of the resulting photonic crystal were investigated. The structure regularity was evaluated with scanning electron microscope graphs and stop band depth achieved in optical absorption spectra. As revealed from the experimental results, photonic crystals of better quality were obtained by using suspending solvents of higher surface tension (water), lower system temperatures (40°C), and sedimentation cell materials of higher critical surface tension of wetting (quartz).     

ZnS-opal与反opal结构ZnS光子晶体的组装

以单分散SiO2微球为基元,在75%～80%湿度、30～45 ℃恒温密闭烘箱中垂直快速组装opal模板;以Zn(NO3)2（0.035 mol/L）、TAA乙醇溶液（0.05 mol/L）为前体,通过溶剂热法充填形成ZnS-opal复合光子晶体;ZnS-opal复合光子晶体在2%～5%的HF溶液中浸泡4～5 h后卸载模板,制得反opal结构ZnS基光子晶体;采用XRD、SEM、ＵV-Vis测试手段对反opal结构ZnS基光子晶体形貌、物相和光学性能进行了表征。结果表明：溶剂热法多次充填可使ZnS纳米晶在模板密堆积形成的空隙中均匀成核;经过酸处理的ZnS-opal中SiO2微球溶解、坍塌,形成蜂窝状三维有序介孔和反opal结构ZnS基光子晶体;相同粒径SiO2微球组装的opal模板、ZnS-opal以及反opal结构ZnS光子晶体均表现出光子带隙特性,但反opal结构ZnS光子晶体带隙位置相比前两者发生了蓝移。     

Fabrication of Metallodielectric Photonic Crystals with a Diamond Structure and their Microwave Properties

Three-dimensional (3D) metallodielectric photonic crystals with a diamond structure were fabricated in order to investigate the formation of stop bands and the absorption ability for microwaves with the dielectric absorbing media embedded into the 3D metal lattice. First, the metallic photonic crystals were prepared by filling the epoxy molds formed by stereolithography with a metal alloy having a low melting point of 70°C, followed by removal of the molds. The metallodielectric photonic crystals were then fabricated by infiltrating the porous metal crystal with a SiC/polyester mixture. The lattice constant of photonic crystals was 15 mm. The effects of different aspect ratios of diamond lattice rods, number of metallic lattice units along Γ-L 〈1 1 1〉, Γ-X 〈1 0 0〉, and Γ-K 〈1 1 0〉 directions, and metallodielectric samples along the Γ-X 〈1 0 0〉 direction on the formation of stop band and microwave absorption ability were investigated in the frequency range from 3 to 30 GHz. Metallodielectric photonic crystals formed showed good absorption ability. The measured transmission spectra of the metallic and metallodielectric crystals agreed well with the simulation of the transmission line modeling method.     

Fabrication of Ceramic–Polymer Photonic Crystals by Stereolithography and Their Microwave Properties

Three-dimensional photonic crystals with periodic variations in the dielectric constant were fabricated using a stereolithographic rapid prototyping method. The structures were composed of millimeter-scale ordered epoxy lattices in which ceramic particles with high dielectric constants (such as silica and titania) were dispersed. These crystals were designed to reflect microwaves via the formation of photonic band gaps in a gigahertz range. The attenuation of transmission amplitude through the photonic crystals, which was measured as a function of frequency using a network analyzer, clearly showed the formation of band gaps in the microwave range.     

InP-SiO2三维光子晶体的制备

用溶剂蒸发法将单分散SiO2微球组装成三维有序结构的胶体晶体,用金属有机化学气相沉积技术向SiO2胶体晶体中填充高折射率材料InP,获得了InP-SiO2两种介质复合的三维光子晶体,通过扫描电子显微镜、X射线衍射、能谱和紫外-可见光谱仪对InP-SiO2三维光子晶体的形貌、结构和光学性能进行了观察测试。研究结果表明：InP在SiO2微球空隙间具有较高的结晶质量,填充较致密均匀、与相同晶格周期的SiO2光子晶体相比,InP-SiO2光子晶体的反射光谱的峰值波长发生明显的红移。     

Fabrication of high‐quality silica photonic crystals on polyester fabrics by gravitational sedimentation self‐assembly

A series of monodispersed silica microspheres with favourable sphericity and different diameters in the range 180–380 nm were prepared by adjusting the concentrations of tetraethylorthosilicate, ammonia, and deionised water by the Stöber method. In different self‐assembly conditions, the quality of silica photonic crystals on a polyester fabric substrate was investigated by field‐emission scanning electron microscopy for the morphology of the crystal structures and by spectrometry for their stop band intensities. High‐quality silica photonic crystals with a face‐centred cubic (fcc) array on polyester fabrics were produced at a low evaporation rate by adopting a high‐relative‐humidity controlled condition with a medium mass fraction of colloidal silica, and exhibited brilliant and variable structural colours, depending on the photonic band gap regulated by the spherical size of the silica microspheres and the viewing angles.     

Silicon-based photonic crystals fabricated using proton beam writing combined with electrochemical etching method

ABSTRACT: A method for fabrication of three-dimensional (3D) silicon nanostructures based on selective formation of porous silicon using ion beam irradiation of bulk p-type silicon followed by electrochemical etching is shown. It opens a route towards the fabrication of two-dimensional (2D) and 3D silicon-based photonic crystals with high flexibility and industrial compatibility. In this work, we present the fabrication of 2D photonic lattice and photonic slab structures and propose a process for the fabrication of 3D woodpile photonic crystals based on this approach. Simulated results of photonic band structures for the fabricated 2D photonic crystals show the presence of TE or TM gap in mid-infrared range.     

Preparation of a three‐dimensional ordered macroporous titanium dioxide material with polystyrene colloid crystal as a template

Polystyrene (PS) photonic colloid crystals were assembled from PS spheres prepared by emulsion‐free polymerization through an improved vertical deposition method that could shorten the assembly time efficiently. The monodispersity of the spheres was appraised according to the standard deviation. The results showed that the PS spheres had a high monodispersity with a standard deviation of 3.7% and a dispersion coefficient of 0.02. The morphology and bandgap structure were observed with scanning electron microscopy images and transmission spectra, respectively. The mechanism of vertical deposition was analyzed simply. As an application of PS colloid crystals, ordered macroporous TiO₂ photonic crystals were prepared, and the structure and properties of macroporous TiO₂ were also studied with various analytical methods, which provided some values for the fabrication of photonic crystals with a complete bandgap. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

High-temperature stable inverse opal photonic crystals via mullite-sol-gel infiltration of direct photonic crystals

Three-dimensionally ordered macroporous materials for photonic or refractory applications have been developed by an innovative approach based on mullite sol-gel infiltration of direct photonic crystals followed by burn-out and calcination. Direct photonic crystals were obtained using polystyrene spheres templates either by vertical convective self-assembly or by drop casting. The samples were then infiltrated by spin coating with mullite sol-gels prepared with two different compositions (74 wt.% Al₂O₃, 26 wt.% SiO₂ and 80 wt.% Al₂O₃, 20 wt.% SiO₂). The inverse opal photonic crystals prepared with both sol-gels presented a highly ordered porosity and the high-alumina composition showed stability up to 1500°C. After inversion of the structure (polymeric template burn-out), the high-alumina composition showed roundness of the PS templated pores closer to an ideal sphere (Ø = 0.967) when compared to the low-alumina composition (Ø = 0.954). Although the inverse opal photonic crystals did not present a photonic bandgap, they showed structural stability at high temperatures, which enable their application as refractory materials.     

Fabrication of imprinted photonic films via predesigned multiple UV-polymerizations and their ability to detect solvents and metal ions in aqueous solution

To synthesize photonic films without a chiral dopant, a predesigned multiple photopolymerization process was carried out. The photonic films were prepared by the photopolymerization of a mixture of chiral nematic liquid crystals. After polymerization, the chiral dopant, CB15, was removed and recycled. The imprinted photonic polymer films showed Bragg reflection without the presence of the chiral dopant. Upon the sensing of solvents in aqueous solution, significant color changes and peak shifts were observed by the naked eye and ultraviolet–visible spectroscopy, respectively. A linear calibration curve between the central wavelength of the reflection band of the fabricated imprinting film and the volume ratio of 1,4-dioxane in water was observed. Furthermore, the sensing of chloroform content in methanol, ethanol, and acetone via the imprinted film were also investigated. The results suggest that the synthesized imprinted photonic films can detect different kinds of mixed solvents. The sensing properties of the photonic films were further improved by copolymerization with a rhodamine-derived monomer. The synthesized modified photonic films can detect heavy metal ions in aqueous solution. This study reports a novel, recyclable, and easy approach to detect organic solvents and copper ions in aqueous solution.