三维SiO2欧泊模板溶剂热法制备硫化锌光子晶体

以单分散二氧化硅微球在重力场下自组装得到的三维有序欧泊(opal)为模板，采用溶剂热法在模板空隙内生长ZnS晶体，从而制备高质量的硫化锌基光子晶体. 通过X射线衍射(XRD)和Raman光谱证明ZnS晶体为闪锌矿结构且晶体质量较好，并对其生长机理进行了讨论. 通过场发射扫描电子显微镜(FESEM)和紫外-可见分光光度计对所合成的ZnS/opal复合物与ZnS反欧泊结构进行了表征，结果表明两种结构都保持了欧泊三维有序性，并且在Г-L方向(垂直于(111)方向)上出现了布拉格衍射峰，说明其具有良好的光子晶体特性.     

Introduction of a planar defect in a molecularly imprinted photonic crystal sensor for the detection of bisphenol A

This paper reports the preparation of a molecularly imprinted inverse opal hydrogel containing a 2D defect layer, by combining the Langmuir-Blodgett technique and the photonic crystal template method. By coupling the exceptional characteristics of molecularly imprinted polymers, sensitive to the presence of a target molecule, and those of photonic crystals in a single device, we could obtain a defect-embedded imprinted photonic polymer consisting in a three-dimensional, highly-ordered and interconnected macroporous array, where nanocavities complementary to analytes in shape and binding sites are distributed. As a proof of concept, we prepared a three-dimensional macroporous array of poly(methacrylic acid) (PMAA) containing molecular imprints of bisphenol A (BPA) and a planar defect layer consisting in macropores of different size. The optical properties of the resulting inverse opal were investigated using reflection spectroscopy. The defect layer was shown to enhance the sensitivity of the photonic crystal material, opening new possibilities towards the development smart optical sensing devices.     

Fabrication and characterization of core-shell photonic crystals via a dipping process

High-quality polystyrene (PS) colloidal photonic crystals in large area were fabricated in 24 h via a capillary-enhanced process. Then, the photonic crystals with core-shell structure were obtained by incorporating silica nanoparticles into the interstitial space of opal template via a dipping process. The filling ratio (V_silica) of interstitial space could be manipulated by dipping colloidal crystals into suspensions with different concentrations of silica nanoparticles, which in turn renders the obtained core-shell photonic crystals. The absorptive peak of opal without dipping process is at 445 nm as measured by UV–vis spectrometry. The filling ratios of 0.130, 0.167 and 0.253 can be calculated according to the modified Bragg's Law, which corresponds to the absorptive peaks for core-shell opals at 453, 463 and 469 nm obtained from suspensions with silica nanoparticles of 0.017, 0.122, and 0.244 wt%, respectively. Therefore, by using this dipping process, the characteristic absorption wavelength for photonic crystal will be varied easily, efficiently and cost effectively than that by traditional methods for constructing opal from monodispersed colloids of different diameters.     

Tunable photonic band gap crystals based on a liquid crystal-infiltrated inverse opal structure

Composite materials comprised of nematic liquid crystals (LCs) and SiO(2) inverse opal films were fabricated. Their optical properties were quite different from those of inverse opal films without the LCs. The optical properties could be controlled by changing the refractive indices of the LCs, which vary with orientation, phase, and temperature. In particular, the optical properties were drastically changed by thermal or photoinduced isothermal phase transitions of the LCs. This means that the photonic band structure could be controlled, and tunable photonic crystals have been achieved, based on the inverse opal structure. The mechanism of this change was investigated by the evaluation of the effective refractive indices. As a result, it was found that the change in optical properties was derived from the orientation of the LC molecules in the voids in the inverse opal film. Furthermore, once the mechanism was understood, it was also possible to control the position of the reflection peak by changing the alignment of the LCs. Such materials have the possibility for practical use in optical devices and fundamental research systems.     

Light harvesting hexamolybdenum cluster integrated with the 3D ordered semiconductor inverse opals for optoelectronic property

Solar energy-harvesting materials have significantly contributed to the development of energy-saving applications for several decades. We have mainly used a new concept composed of the electrophoretic deposition technique and photonic crystal structural engineering to understand the tunable light-absorption and electronic conduction properties. A hexamolybdenum cluster compound (denoted as the Mo₆ cluster) was successfully functionalized on a tin pyrophosphate semiconductor integrated within an inverse opal photonic crystal. The size of the periodical pores, surface modification, and chemical composition of the infiltration material of the inverse opal film have been investigated to control the photonic bandgap in the visible range and the efficiency of the deposited Mo₆ cluster. The photoactive Mo₆ clusters act as a visible light harvester and generate an efficient photo-induced current upon light absorption that is enhanced by a slow photon effect occurring at the photonic stopband edges. The electron and proton are transferred in the inorganic-organic network via hydrogen bonds by a hopping mechanism to generate a rapid photoconductivity response during light irradiation. Specific attention focused on the role of humidity and temperature regarding the reproducibility of the experiments and the photosensitivity of the nanocomposite. The suitable tunable photo-induced conduction property in organic-inorganic materials opens a new opportunity for the applicability of cluster-based compounds in visible optoelectronic devices.     

Layer transfer approach to opaline hetero photonic crystals

By taking advantage of the hydrophobicity of dry polystyrene colloidal crystal (opal) films and the large surface tension of water, a convectively self-assembled polystyrene opal film on a hydrophilic glass substrate can be peeled off from the substrate and floated on the water surface. A layer transfer technique was developed to sequentially stack floating opal films of different sphere sizes, resulting in opaline hetero photonic crystals. The feasibility of this technique to planar defect engineering in a self-assembled colloidal photonic crystal was also demonstrated. Both structural observation and optical characterization confirmed the crystalline integrity of the resultant opaline heterostructures.     

Inverse opal photonic crystal of chalcogenide glass by solution processing

Chalcogenide opal and inverse opal photonic crystals were successfully fabricated by low-cost and low-temperature solution-based process, which is well developed in polymer films processing. Highly ordered silica colloidal crystal films were successfully infilled with nano-colloidal solution of the high refractive index As(30)S(70) chalcogenide glass by using spin-coating method. The silica/As-S opal film was etched in HF acid to dissolve the silica opal template and fabricate the inverse opal As-S photonic crystal. Both, the infilled silica/As-S opal film (Δn ~ 0.84 near λ=770 nm) and the inverse opal As-S photonic structure (Δn ~ 1.26 near λ=660 nm) had significantly enhanced reflectivity values and wider photonic bandgaps in comparison with the silica opal film template (Δn ~ 0.434 near λ=600 nm). The key aspects of opal film preparation by spin-coating of nano-colloidal chalcogenide glass solution are discussed. The solution fabricated "inorganic polymer" opal and the inverse opal structures exceed photonic properties of silica or any organic polymer opal film. The fabricated photonic structures are proposed for designing novel flexible colloidal crystal laser devices, photonic waveguides and chemical sensors.     

Thermoresponsive inverse opal films fabricated with liquid-crystal elastomers and nematic liquid crystals

Liquid-crystal elastomers together with nematic liquid crystals have been used as inverse opal materials to fabricate thermoresponsive photonic crystal directly. In the vicinity of the phase-transition point of the mixture, the photonic band gaps of such inverse opal films exhibited a strong temperature dependence. As the molar ratio of liquid-crystal elastomers and nematic liquid crystals changed, the character of their PBGs also changed with increasing temperature. Such a temperature-tuning effect in the photonic band gap should be of great interest in thermal switches and thermal sensors.     

蛋白石及反蛋白石結構光子晶體

光子晶体是由不同介电常数的材料构成的一种空间周期性结构，它能够在特定方向上禁阻、控制和操纵光子的运动。目前，已制备的光子晶体具有几种不同的结构类型，本文主要综述了蛋白石、反蛋白石结构光子晶体的制备方法及其光子带隙的影响因素。     

Preparation and characterization of Pb<Subscript>0.56</Subscript>Sr<Subscript>0.44</Subscript>Zr<Subscript>0.52</Subscript>Ti<Subscript>0.48</Subscript>O<Subscript>3</Subscript> inverse opal

Pb_0.56Sr_0.44Zr_0.52Ti_0.48O₃ (PSZT) inverse opal photonic crystals (PCs) have been synthesized by a process of self-assembly in combination with a sol–gel procedure. PSZT inverse opals show pure perovskite structure with good orders in three dimensions. The evident photonic band gaps have been observed in the transmittance spectra with a blue-shift phenomenon due to the decrease of opal template periods. PSZT inverse opals also exhibit the reflection peaks in basic agreement with the calculated results. This three-dimensional (3D) ordered PSZT inverse opals have shown interesting optical characteristics and potential applications in optoelectronic and photonic devices.     

胶体晶体自组装排列进展

自组装排列胶体晶体是发展光子晶体等亚微米周期有序结构及新型光电子器件十分重要的环节.高电荷密度单分散胶体球在较弱的离子强度和稀浓度下会自发排列形成紧密堆积的周期性结构(ccp),常常是面心立方(fcc),科学家们以此为基础发展了多种结晶化胶体粒子的方法,包括重力场沉积、电泳沉积、胶体外延技术、垂直沉积、流通池、物理束缚排列及其他的许多方法.目前排列的胶体粒子基本为球形,材料也多为SiO2、PS、PMMA,此外一些复合粒子,主要为核壳粒子的排列这里也稍作介绍,这些方法及其变通的使用可以形成类蛋白石及反蛋白石结构,最终实现光子带隙及其它多种用途。     

反蛋白石光子晶体的研究进展

反蛋白石晶体是一类重要的光子晶体,由于其制备材料的广泛性以及容易实现对光子禁带的多重调制而受到广泛关注.本文介绍了目前反蛋白石晶体结构的主要制备技术和方法,详细阐述了反蛋白石晶体结构的最新研究进展.     

Modulation of spontaneous emission characteristics of Alq3 in three‐dimensional PMMA photonic crystals

The effect of the photonic stop bands (PSBs) on the spontaneous emission from tris(8‐hydroxyquinolinato)aluminum (Alq3) doped in the beads of polymethylmethacrylate opal photonic crystals (PCs) is investigated in detail. The structure of PSBs in PCs has been analyzed. The steady emission data exhibits that the first‐ and second‐order PSB could effectively influence the spectral characteristics of Alq3 through changing the incident angles. The emission dynamic data is also investigated by using the Kohlrausch strengthened exponential model, which shows that the emission decay rate of Alq3 can be decelerated as the PSB of PC approaches the emission peak of Alq3. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 842–847     

A Luminescent Dicyanodistyrylbenzene-based Liquid Crystal Polymer Network for Photochemically Patterned Photonic Composite Film

A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network (LCN)was fabricated by using a silica colloidal crystal as a template.The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties,respectively.A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN.More importantly,the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation.On the basis of this effective phototuning process,microscopic patterning ofphotonic film was developed under both fluorescence mode and reflection mode.The work demonstrated here provides a new route to construct photo-responsive photonic film.     

Photoswitching properties of photonic band gap material containing azo-polymer liquid crystal

A photochemically tunable photonic crystal was prepared by infiltration of the polymer liquid crystal (LC) having azo-chromophores in a SiO₂ inverse opal structure. The SiO₂ inverse opal film infiltrated with the polymer LC reflected a light corresponding to the periodicity as well as the refractive indices of the inverse opal structure. Linearly polarized light irradiation caused the shift of the reflection band to longer wavelength more than 15 nm. This is caused by the formation of uniaxially anisotropic molecular orientation of the polymer LC. The switched state was stable under interior light, and reversible switching of the reflection band can be achieved by the linearly and circularly polarized light irradiation. This photoswitching property will be suitable not only for various optical materials, but also for introduction of defects in the photonic crystals.     

Fabrication and characterization of cerium-doped barium titanate inverse opal by sol-gel method

Cerium-doped barium titanate inverted opal was synthesized from barium acetate contained cerous acetate and tetrabutyl titanate in the interstitial spaces of a polystyrene (PS) opal. This procedure involves infiltration of precursors into the interstices of the PS opal template followed by hydrolytic polycondensation of the precursors to amorphous barium titanate and removal of the PS opal by calcination. The morphologies of opal and inverse opal were characterized by scanning electron microscope (SEM). The pores were characterized by mercury intrusion porosimetry (MIP). X-ray photoelectron spectroscopy (XPS) investigation showed the doping structure of cerium, barium and titanium. And powder X-ray diffraction allows one to observe the influence of doping degree on the grain size. The lattice parameters, crystal size and lattice strain were calculated by the Rietveld refinement method. The synthesis of cerium-doped barium titanate inverted opals provides an opportunity to electrically and optically engineer the photonic band structure and the possibility of developing tunable three-dimensional photonic crystal devices.     

HCl/NH_3敏感的卟啉-二氧化硅反蛋白石光子晶体荧光传感器

将反蛋白石结构的光子晶体引入到腐蚀性气体检测体系,制备得到卟啉-二氧化硅反蛋白石光子晶体(TPP-SiO_2IOPCs)荧光传感器。相对于空白样,TPP-SiO_2IOPCs传感器实现了氯化氢(HCl)气体检测信号200倍的增强,这主要归因于反蛋白石型光子晶体的大孔结构和慢光子效应。同时,TPP-SiO_2IOPCs传感器对于HCl气体的猝灭效率可达75%,比空白样的提高了25%,而且经HCl气体处理后的传感器通入氨气(NH_3)后,初始的荧光强度几乎完全恢复。在HCl和NH_3条件下进行5个循环后,TPP-SiO_2IOPCs传感器表现出良好的可重复使用性。该研究对于发展高效的荧光传感器提供了新的思路。     

红荧烯反蛋白石的制备及其光学性质研究

通过表面浸润法制备了红荧烯的反蛋白石结构,成功观测到其结构色,并检测出相对应反射光谱.此类方法可进一步拓展制备多种具有三维有序大孔结构的有机半导体材料,得到新的光电性质.     

Enhanced photochemical‐shift of reflection band from an inverse opal film based on larger birefringent polymer liquid crystals: Effect of tolane group on the photochemical shift behavior

Photo‐chemically tunable photonic band gap materials are prepared by infiltration of liquid crystal polymers having azobenzene groups into voids of SiO₂ inverse opal films. Linearly polarized (LP) light irradiation results in transformation from a random to an anisotropic molecular orientation of azobenzene side chains in the voids of the SiO₂ inverse opal film, leading to the reversible and stable shift of the reflection peak to longer wavelength more than 15 nm. To improve switching properties, we use copolymers of azobenzene monomer and tolane monomer, which have higher birefringence, as infiltration materials into the voids. The azobenzene‐tolane copolymers are found to show higher birefringence than azobenzene homopolymers by the LP light irradiation at higher temperature. Consequently, the reflection band of the SiO₂ inverse opal film infiltrated with the azobenzene‐tolane copolymer can be shifted to longer wavelength region more than 55 nm by the irradiation of LP light. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1981–1990, 2009     

Fabrication of Cs2.5H0.5PW12O40 three-dimensional ordered film by colloidal crystal template

A three-dimensional ordered polyoxometalate periodic film was synthesized using dodecatungstophosphoric acid (H₃PW₁₂O₄₀) and Cs₂CO₃ as precursors and colloidal crystals as templates by an inverse opal method. The samples were characterized by elemental analysis, XRD, IR spectra, UV-Vis diffuse reflectance spectra (DR-UV-Vis) and SEM techniques. This arrayed film constructed by pure cesium salt of dodecatungstophosphoric acid Cs_2.5H_0.5PW₁₂O₄₀ nanoparticles shows well-defined lamellar array with inverse opal structure, which exhibits a well-defined photonic band gap.