TiO2掺杂调控聚苯乙烯微球折射率及胶体光子晶体结构色

胶体光子晶体由于其可调变的结构色在绿色印刷、印染等领域备受关注,而其光子带隙的宽度和位置由光子晶体的晶格参数(晶面间距,通常受胶体微球尺寸影响)和介质的折射率决定。现有人工胶体光子晶体主要基于SiO_2和高分子(如聚苯乙烯(PS)等)微球的组装制备,由于胶体微球材质种类有限,折射率调控受限,因而目前调控胶体光子晶体结构色主要靠改变胶体微球的尺寸来实现。本文首先制备高折射率(2.6)的TiO_2纳米晶,在乳液聚合制备单分散的PS(折射率1.6)微球过程中,将所制备的TiO_2纳米晶掺杂于PS微球中,通过TiO_2的掺杂量有效调控胶体微球的折射率,进而实现胶体光子晶体的结构色调控。以多色胶体光子晶体微球的水溶液为墨水,采用彩色喷墨打印技术打印了电脑设计的光子晶体彩画。本文发展的光子晶体结构色调控新技术拓展了胶体光子晶体的应用。     

胶体光子晶体的平面介电常数缺陷

为引入特殊的光学性质,通常需要在三维光子晶体中人为可控地引入缺陷.通过改变局部结构单元的尺寸或介电常数,相应地引入给体或受体掺杂,带来不同的缺陷态.以前文献报道的向胶体光子晶体中引入缺陷,常会因为同时引入尺寸和介电常数掺杂,给掺杂性质的界定带来困难.本文中,我们结合对流自组装法和L-B膜法,在实心二氧化硅微球组成的三维光子晶体内引入尺寸相同的二氧化硅空心球(与实心球相比具有不同折光率)组成的单层平面缺陷,或者在空心球晶体内引入实心球缺陷层,构成实心-空心-实心或空心-实心-空心的三明治结构,在不破坏整体晶格的同时,在三维胶体光子晶体中引入单一的平面介电常数缺陷.     

三维胶体光子晶体对光的调控与应用研究

21世纪在光子技术领域中操控光子已成为核心的研究内容.胶体光子晶体因其特殊的周期结构而具有光子禁带的特性,从而可以对特定频率的光进行调控,其应用涵盖了光、电、催化、传感、显示、检测等众多领域,为光功能材料的结构设计和性能优化提供了参考依据.本文主要从两个方面阐述近年来胶体光子晶体对光的调控作用与应用,一方面,光子晶体的...     

凝胶光子晶体*

光子晶体是一种介电常数（或折射率）可以周期性调制的结构,其自激辐射抑制和光子局域化性质使其可以简便而有力的限制、控制和调控光子。近年来,利用胶体晶体自组装性质与水凝胶的传统应用相结合制成的凝胶光子晶体在药物释放、光学开关、金属探针、生物传感器等的新应用方面的研究蓬勃发展,在新材料开发及临床应用等方面取得巨大进展。本文概述了胶体晶体自组装并对该类凝胶光子晶体进行了分类介绍并对其发展趋势进行了评述和展望。     

胶体光子晶体膜的超浸润性研究进展

近年来,由于具有特殊浸润性的胶体光子晶体膜在传感、检测、催化等方面的重要应用,胶体光子晶体膜的超浸润研究受到科研工作者的广泛关注.本文阐述了包括超亲液、超疏液、两亲性、梯度浸润性、可调控浸润性、图案浸润性等具有特殊浸润性光子晶体膜的制备及其相关应用,并讨论疏水、超疏水和亲-疏图案不同浸润性基底对所制备胶体光子晶体膜的功能性及其相关应用的影响.该工作对于发展新型功能型材料器件的制备具有重要的借鉴及指导意义.     

仿生制备功能性聚合物光子晶体

简述了自然界生物光子晶体经过不断的进化与演变而具有的一些特殊的性能,如亮丽的结构色彩、特殊的浸润性及高强度.受自然界生物光子晶体的这些特殊性能启发,通过对聚合物乳胶粒硬核软壳结构、表面功能基团及表面形貌的设计和调控等方法仿生制备了具有特殊浸润性的光子晶体;并在胶体晶体的聚合物乳胶粒间引入光交联聚合物,制备得到高强度的光子晶体;通过对蘑菇头形状乳胶粒两端的浸润性差异的设计制备,组装得到新型的各向异性结构的光子晶体.进一步发展了这些功能性光子晶体在湿度检测、油传感、自振荡体系等方面的应用.发展了通过喷涂、打印方法实现大面积、图案化聚合物光子晶体的简单制备.     

基于胆甾相液晶的可调制光子晶体

将胆甾相液晶填充进胶体晶体内部空隙, 通过胆甾相液晶与胶体晶体的耦合, 构建了一种新型可调制液晶光子晶体. 填充于胶体晶体内部的胆甾相液晶织构呈现典型的手性近晶相(S)特征. 由于胆甾相液晶具有特定的选择性反射, 当胶体晶体的带隙处于胆甾相液晶的反射波长范围之内, 则随着温度的改变, 胶体晶体的带隙与胆甾相液晶的带隙同时发生蓝移. 在一定温度条件下, 胆甾相液晶的带隙将与胶体晶体的带隙发生耦合, 实现了光子晶体带隙在单峰与双峰之间的可逆切换.     

化学响应性光子晶体

光子晶体是一种具有光子带隙结构的周期性电介质材料,如果将响应性材料组装到光子晶体结构中,所形成的光子晶体的带隙结构则对外界环境的变化具有响应性,而被称为响应性光子晶体。响应性光子晶体作为光子晶体的一个新领域,由于其在传感器,生物医学,临床检测等方面的潜在应用,近几年受到广泛关注。根据外界环境的不同,响应性光子晶体可简单分为化学响应性光子晶体、物理响应性光子晶体和生物响应性光子晶体等。本文将对化学响应性光子晶体的国内外研究动态做一简要介绍,重点介绍以下五种化学响应性光子晶体:金属离子响应光子晶体、pH响应光子晶体、氧化还原响应光子晶体、葡萄糖响应光子晶体和光化学响应光子晶体。     

ZnO光子晶体的制备和光学特征

通过制备过程中严格分离晶核的形成和生长两步骤, 成功获取了直径一致的单分散ZnO胶体球, 并通过控制晶核的数量来调节胶体球大小. 利用扫描电子显微镜和X射线衍射仪对其进行了结构和成分表征. 通过加热条件下的重力场自组装, 把ZnO单分散胶体球的浓缩液滴到140 ℃下的各种不同的基底上, 随着溶剂蒸发, 胶体球自组装成光子晶体, 最后测量了光子晶体的光透过率, 胶体球直径为220、250 nm的光子晶体分别具有对应着中心波长为460、540 nm的光子带隙.     

金属AI薄膜基微池强制沉积胶体光子晶体的制备

强制沉积法是一种利用自组装原理快速沉积胶体晶体有序阵列的模板方法.我们利用微机械刻划法加工金属Al薄膜,Al膜厚控制微粒粒径和聚醚砜膜厚控制层数,成功地制备了用于强制沉积光子晶体的微池装置.为了检验该微池装置的有效性,我们分别测试了不同粒径(224,245和283 nm)单分散聚苯乙烯微球的沉积效果,并且对其中一种微球(283 nm)进行了不同温度的烘干处理,检验了烘干温度对该样品表面形貌和光子带隙中心波长的影响.实验结果表明,该光子晶体呈面心立方结构,内部晶格完整,缺陷较少,带隙中心波长的实验值与计算值符合得较好.此外,烘干处理可以使构成光子晶体的微球发生微观变化,并导致光子带隙中心波长的蓝移.     

Colloidal photonic crystals with a graded lattice-constant distribution

In this work, a gradient polystyrene colloidal photonic crystal was fabricated by annealing in a graded temperature field. The lattice constant of the gradient crystal gradually varied along the temperature-gradient direction. The positional bandgap wavelength as well as the attenuation of the bandgap wavelength could be tuned dependent on the position of the gradient colloidal crystal along the gradient direction because of the lattice-constant variation.     

金属Al薄膜基微池强制沉积胶体光子晶体的制备

强制沉积法是一种利用自组装原理快速沉积胶体晶体有序阵列的模板方法. 我们利用微机械刻划法加工金属Al薄膜, Al膜厚控制微粒粒径和聚醚砜膜厚控制层数, 成功地制备了用于强制沉积光子晶体的微池装置. 为了检验该微池装置的有效性, 我们分别测试了不同粒径(224, 245和283 nm)单分散聚苯乙烯微球的沉积效果, 并且对其中一种微球(283 nm)进行了不同温度的烘干处理, 检验了烘干温度对该样品表面形貌和光子带隙中心波长的影响. 实验结果表明, 该光子晶体呈面心立方结构, 内部晶格完整, 缺陷较少, 带隙中心波长的实验值与计算值符合得较好. 此外, 烘干处理可以使构成光子晶体的微球发生微观变化, 并导致光子带隙中心波长的蓝移.     

Analysis on Band Gaps of MCM-41 Type of Materials

The concept and analysis method of photonic crystals and band gaps are introduced into one-dimenslonal (1D) ordered mesoporous materials. MCM-41 type of materials are treated theoretically as photonie crystals. The formation of band gaps is exhibited and confirmed by a calculation of transfer matrix technique. PBG was found around 9-42 nm in soft X-ray region. The photonie band-gap was predicted to be dependent on incident direction, pore size and lattice constant. The mesoporous materials with different pore sizes and different lattice constants have different band-gap widths.     

FABRICATION OF PHOTONIC CRYSTAL WITH SUPERLATTICES

A novel technique was used to fabricate three-dimensional photonic crystals with superlattices. The super structure was fabricated by assembling monodispersed microspheres in the grooves of the scales of morpho butterfly, which makes the photonic crystal being composed of two kinds of different photonic structures (natural groove structure of butterfly wing and artificial microspherical colloids arrangement). The superstructural photonic crystal exhibits some unique optical properties different from both the butterfly wing and the colloidal crystal. The approach exhibited here provides a new way for fabricate photonic crystals with superlattices.     

Photonic band structures of colloidal crystals measured with angle-resolved reflection spectroscopy

We acquired angle- and polarization-resolved reflection spectra from a colloidal crystal made of polystyrene spheres along the two perpendicular directions corresponding to the LU and LW directions in the first Brillouin zone of an fcc lattice. Dispersion relations between the reflection peak positions and the wave vectors of the incident light were obtained from the measured spectra and compared with calculated photonic band structures. For the first stop band region in the spectra, the behavior of the reflection peak due to Bragg diffraction agreed with the calculated band structure and revealed some differences induced by the polarization and crystalline orientations. The spectral features observed in the higher energy regions also revealed these differences. In addition, dispersion relationships between the peak positions and the wave vectors were obtained from the results of fitting each spectrum with several Gaussian curves, compared with the calculated photonic band structures. The relationships obtained for the LU direction almost matched the calculated band structure, while the relationships obtained for the LW direction revealed the features of the mixed band structure calculated for the two perpendicular directions. These results indicate that angle- and polarization-resolved reflection spectroscopy has the potential to experimentally analyze the photonic band structures of actual photonic crystals.     

FABRICATION OF PHOTONIC CRYSTAL WITH SUPERLATTICES

1. INTRODUCTION The very latest subject of physics to surface in biology is the photonic crystal, which is ordered, subwavelength structured material capable of controlling the propagation of light in the similar manner as which atomic crystal control electrons [1,2]. Due to the application of the photonic crystal in laser, integrated optical circuit, it attracted great attention in the past decade. Photonic crystals can be fabricated by microfabrication methods, holographic methods, and c…     

光子晶体的制备及应用

光子晶体（PC）是具有光子带隙的周期性电介质结构，频率落在光子带隙中的光将被禁止传播。本文对光子晶体的能带结构、带隙的产生、制备方法及应用作了简要的介绍，重点介绍了光子晶体的制备技术及其在光电领域中的应用前景。     

Photo-induced Birefringence of Azo-dye Based on Three-dimensional Opal Photonic Crystals

A series of three-dimensional opal photonic crystals based on the polymer was synthesized and applied in the field of photo-induced birefringence. The data show that the photo-induced birefringence(PIB) of pure Sudan III film could be enhanced by increasing the thickness of azo films. When Sudan III was distributed on the three-dimensional opal photonic crystals, the photo-induced birefringence process could be modulated. In addition, the data also exhibit that the PIB processes with different pumping polarization directions are sensitive to the role of photonic crystals. The results could be beneficial to further understanding the photo-induced birefringence and utilizing the photonic crystals.     

Microwave-assisted self-organization of colloidal particles in confining aqueous droplets

Monodisperse aqueous emulsion droplets encapsulating colloidal particles were produced in the oil phase, and controlled microwave irradiation of the aqueous drop phase created spherical colloidal crystals by so-called evaporation-induced self-organization of the colloidal particles. Unlike usual colloidal crystals, colloidal crystals in spherical symmetry (or photonic balls) possessed photonic band gaps for the normal incident light independent of the position all over the spherical surface. While the consolidation of colloidal particles in emulsion droplets in an oven took several hours, the present microwave-assisted evaporation could reduce the time for complete evaporation to a few tens of minutes. Under the microwave irradiation, the aqueous phase in emulsions was superheated selectively and the evaporation rate of water could be controlled easily by adjusting the microwave intensity. The result showed that the packing quality of colloidal crystals obtained by the microwave-assisted self-organization was good enough to show photonic band gap characteristics. The reflectance of our photonic balls responded precisely to any change in physical properties including the size of colloidal particles, refractive index mismatch, and angle of the incident beam. In particular, for polymeric particles, the photonic band gap could be tuned by the intensity of microwave irradiation, and the reflection color was red-shifted with stronger microwave irradiation. Finally, for better photonic band gap properties, inverted photonic balls were prepared by using the spherical colloidal crystals as sacrificial templates.