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...     

TiO_2反蛋白石光子晶体最新研究进展

TiO_2反蛋白石光子晶体的研究近年来受到广大科技工作者的关注。它具有TiO_2的无毒、高折射率、良好的生物相容性,并且在电化学、光催化等方面有着优良的特性,而且具有光子晶体的光子带隙、光子局域、慢光效应、超棱镜效应、负折射效应等光学特性,使其在化学传感器、太阳能电池、光催化、高效率微波电线以及光子晶体纤维等方面具有广阔的应用前景。本文总结了TiO_2反蛋白石光子晶体的制备方法、改性方法,同时介绍了其近年来在各领域的应用研究进展。     

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。     

快速响应聚合物光子晶体研究进展

响应性光子晶体以其亮丽的结构色彩及光学信号对外场刺激的响应性变化,在化学传感、智能显示等领域具有重要的应用前景.本文综述了快速响应聚合物光子晶体的研究进展.首先从原理上阐述了影响溶胀型光子晶体响应速率的因素,系统总结了针对不同因素提高其响应速率的研究工作,着重探讨了溶胀型光子晶体水凝胶的尺寸、聚合物链段的物理化学性能(包括多孔结构和亲疏水性)、凝胶网络的交联度等因素对响应速率的影响.同时也简要介绍了影响非溶胀型响应性光子晶体,如光、电、磁、机械力等外场诱导体系折光指数变化的响应性光子晶体的响应速率的因素.最后展望了响应性光子晶体的热点研究方向.这些工作对于提高光子晶体的响应速率,发展其在实时分析、在线检测等领域的应用具有重要意义.     

慢光子效应在太阳能转换燃料中的应用（英文）

随着全球性能源短缺和环境恶化问题的日益突出,能源和环境问题已成为目前人类面临和亟待解决的重大难题,研究新的替代能源和清洁环境技术备受关注.世界各国的科研工作者都在积极探索和寻找有效的对策,其中通过光催化分解水和还原CO_2将太阳能转化为有价值的氢气和碳氢燃料可有效缓解人类对可再生能源和清洁能源的需求.然而,现有催化剂的转换效率还达不到商业化的要求,主要原因是太阳光的利用率低和光生电荷的复合率高.将催化剂构造成三维有序孔状的光子晶体结构,可有效提高催化剂对光的利用率.光子晶体是一种特殊的周期性介电物质有序排列而成的微结构材料,它对光有着特殊的调控作用,可以通过光反射、光散射和慢光子效应来调控光在材料介质结构中的传播和光与介质的相互作用.三维反蛋白石结构的光子晶体不仅有光子晶体的特征还具有本身特有的结构效应,主要体现在以下两个方面:(1)光子晶体结构:光子晶体具有内部相互连接的三维框架结构和相互连通的球形孔道,三维框架结构提供大的比表面积,而有序的球形孔道有利于反应物分子的动态扩散;(2)光子晶体效应:当光波长落在光子禁带范围内,此波长的光将会被反射而不能在材料内传播;当光子晶体材料内有缺陷时可以发生多重散射,增加光的利用率;当光波长落在光子禁带红边的时候,这部分的光将会"慢下来"并且作用光子晶体的高介电物质部分;当光波长落在光子禁带蓝边的时候,这部分光也会"慢下来"并且作用于光子晶体的低介电物质部分.通过调控光子禁带的位置,可以得到不同波长的慢光子和调控作用于不同的材料物质上,增强入射光的利用率和光与材料的相互作用.基于光子晶体半导体材料既有电子能带又有光子能带的特点,利用光的反射、散射和慢光子效应来调控光在光子晶体中的传播,能显著增强光与催化剂的相互作用.尤其是光子禁带附近产生的慢光子效应对光有着特殊的调控作用,可以减慢一些特定频率的入射光在催化剂中的传输,促进催化剂对光的吸收.同时,慢光子效应还能促进光生电子-空穴对的分离,提高光解水产氢和光化学还原CO_2的活性.本文总结了光子晶体的慢光子效应促进光催化产H_2和CO_2还原的最新发展,并研究了慢光子效应在太阳能转换为燃料中的作用.基于慢光子效应对光的特殊调控作用,构造具有光子晶体结构的催化剂对促进太阳光的吸收和提高太阳能转换为燃料的效率具有重要的意义.     

流动控制沉积法制备PMMA叠层光子晶体薄膜及其光学性能研究

采用流动控制沉积法, 通过调控泵速和聚甲基丙烯酸甲酯(PMMA)胶体微球溶液的浓度, 制备出微球排列高度有序且薄膜紧密附着于基底的高质量光子晶体薄膜. 获得了制备高质量PMMA光子晶体薄膜的组装条件范围, 发现在该条件范围内, 当泵速或胶体微球溶液浓度一定时, PMMA光子晶体薄膜的厚度随胶体微球溶液浓度的增加或泵速的降低而增加. 研究了组装条件对PMMA光子晶体薄膜光学性能的影响, 发现光子禁带位置随光子晶体薄膜厚度增加或减少而红移或蓝移. 在此基础上, 控制组装条件得到了不同尺寸微球堆叠而成的叠层光子晶体薄膜, 并研究了其光学性能的变化规律. 结果显示, 叠层光子晶体薄膜的光子禁带峰为各层叠层光子晶体禁带峰的简单叠加, 且峰强度受光入射角方向影响.     

金属基光子晶体的研究进展

以具有独特功能的金属基材料（或其氧化物）及复合材料作为构筑单元制备的金属基光子晶体展现出优良的光学性能及光电转化性能,这对于拓展光子晶体在未来新型能源开发领域的应用前景具有重要意义. 综述了金属基光子晶体的制备方法、性能研究及其应用进展,并对金属基光子晶体在未来新型能源开发等方面的应用前景进行了展望.     

光子晶体传感器研究进展

光子晶体因其独特的光学性质,在传感器方面具有重要的应用价值.光子晶体构筑的传感器可以实现高灵敏的荧光检测和色度检测.本文综述了光子晶体传感器在荧光检测和色度检测中的相关工作,阐述其工作原理,并总结了光子晶体传感器的最新研究趋势.     

SiO_2@PANI光子晶体的制备及电致变色性能研究

应用Stber法合成单分散SiO2微球,通过垂直沉积自组装光子晶体,由电化学法在所组装的SiO2微球表面生成聚苯胺(PANI),得到了核-壳结构SiO2@PANI光子晶体薄膜.测试了SiO2@PANI光子晶体薄膜的循环伏安曲线、多电位紫外吸收光谱、对比度、响应时间等电致变色性能,结果表明,该光子晶体薄膜在变色时颜色亮丽,其最大对比度可达77%,远高于单纯PANI薄膜的43%,同时响应时间变快.初步实验结果说明将光子晶体结构引入导电聚合物中,能够提高其电致变色性能.     

胶体晶体微球及其生物医学应用

光子晶体(PhCs)是由单分散纳米粒子周期性排列形成的材料,具有光子禁带,频率落在光子禁带内的光被禁止传播,这个特性激起了研究者对其制备和应用的研究热情。然而,一般的光子晶体材料都具有角度有偏性质,限制了其在宽视角光学材料和设备上的应用。近几年有一系列围绕球形胶体光子晶体材料的研究成果问世,由于球形的对称性,球形胶体晶体的衍射峰不会随着光的入射角变化而发生变化,从而拓宽了胶体晶体的应用范围。随着微流控技术被用于制备液滴模板,球形胶体晶体的制备取得了巨大的进步。微流控技术不仅保证了液滴模板的单分散性,还增加了胶体晶体微球的结构与功能的多样性。胶体晶体微球这些特有的性质,可以很好地将光子晶体材料与编码、非标记检测、细胞培养以及载药等生物医学领域连接起来,为其应用提供了广阔的前景。本文总结了球形光子晶体的研究进展,包括球形光子晶体的设计、制备及其生物医学应用,最后,对球形光子晶体未来的发展方向作了展望。     

二维分子晶体的研究进展

二维分子晶体具有超薄、长程有序、无晶界和缺陷密度低等优点,是构建多种高性能光电器件的理想材料.实现二维分子晶体的低成本、大面积制备是二维分子晶体走向应用的关键.目前,人们开发了多种方法,在气相和液相中实现了二维分子晶体的可控制备,并揭示了这类二维有机体系独特的光电性能.本文综述了二维分子晶体的制备方法及其在有机场效应晶...     

Control of the optical band structure of liquid crystal infiltrated inverse opal by a photoinduced nematic-isotropic phase transition

Recently, photonic band gap (PBG) crystals with lattice parameters comparable to the wavelength of light have attracted much attention, because they offer unique ways in which to control the propagation of light. PBG crystals have applications in laser, quantum optical devices, and so on. For many of these applications, it is important to have the capability of tuning the photonic band structures. The fabrication of such tunable PBG crystals is still a challenge. In this paper, we proposed that switchable PBG crystals could be realized by taking advantage of the phase transition in liquid crystals induced by the photoisomerization of azo dyes. A dynamic change in the optical stop band was demonstrated. Such photoswitchable PBG crystals provide a method by which light can be routed using light.     

光子晶体在分析化学中的应用

光子晶体是一新兴的光学材料,正越来越多地应用于分析化学领域,有可能成为新的研究热点。本文着重介绍与分析化学相关的光子晶体研究,特别关注其在色谱、毛细管与芯片电泳等分离分析方面的应用。     

Super- and Ferroelastic Organic Semiconductors for Ultraflexible Single-Crystal Electronics

Like silicon, single crystals of organic semiconductors are pursued to attain intrinsic charge transport properties. However, they are intolerant to mechanical deformation, impeding their application in flexible electronic devices. Such contradictory properties, namely exceptional molecular ordering and mechanical flexibility, are unified in this work. We found that bis(triisopropylsilylethynyl)pentacene (TIPS-P) crystals can undergo mechanically induced structural transitions to exhibit superelasticity and ferroelasticity. These properties arise from cooperative and correlated molecular displacements and rotations in response to mechanical stress. By utilizing a bending-induced ferroelastic transition of TIPS-P, flexible single-crystal electronic devices were obtained that can tolerate strains (ϵ) of more than 13 % while maintaining the charge carrier mobility of unstrained crystals (μ>0.7 μ₀). Our work will pave the way for high-performance ultraflexible single-crystal organic electronics for sensors, memories, and robotic applications.     

Rapid Growth of Halide Perovskite Single Crystals: From Methods to Optimization Control

Metal halide perovskites are emerging as new generation optoelectronic materials due to their high carrier mobility, long carrier diffusion length and large light absorption coefficient, which have broad applications in solar cell, light‐emitting diode, laser, photodetector and transistors. Perovskite single crystal is an ideal platform for discerning the intrinsic properties of these materials. In some cases, perovskite single crystals are better candidates to gain high performance optoelectronics. However, the growth of perovskite single crystals is time and cost consuming, which has an obvious disadvantage for device exploration. Therefore, fast growth technique is highly desirable in not only promoting the use of perovskites in commercial applications but also facilitating deep physical investigation of the materials. In this review, we summarize thoroughly the development of fast growth of the halide perovskites single crystal. Specifically, we highlight the progress of rapid growth techniques with emphasis on the optimization control.     

Design of chiral dimesogens containing cholesteryl groups; formation of new molecular organizations and their application to molecular photonics

Photoresponsive liquid crystals and organogels are finding increasing application in information technology and photonics. In this tutorial review, the authors describe how weak intermolecular interactions facilitate molecular organization of cholesterol-containing dimesogens to form such materials. Design considerations and photoresponsive properties of both organogels and glassy liquid crystals are discussed and their applications to molecular photonics highlighted. The review will be of value to readers interested in the development of new materials which respond to the different properties of light.     

Liquid crystalline polymers: From self-organization to functions and applications

Liquid crystals derive their unusual properties and their broad range of applications from their unique spatial and orientational order giving rise to specific symmetries, to strong anisotropies with respect to macroscopical properties and to a strong coupling to external fields. We have studied for liquid crystalline polymers modes of inducing strong modifications of the anisotropic optical properties locally in solid films by light. A storage process is described in this contribution which is based on light-induced trans-cis-trans-isomerization reactions of azobenzene chromophores attached to a polymer backbone as side groups in liquid crystalline polymers. The chromophores are able to rotate in the glassy state if subjected to linearly polarized light: the azobenzene units approach a saturation orientation which is perpendicular to the polarization direction of the light. The contribution discusses the molecular mechanism of this process as well as possible applications.     

Photomechanical Organic Crystals as Smart Materials for Advanced Applications

Photomechanical molecular crystals are receiving much attention due to their efficient conversion of light into mechanical work and advantages including faster response time; higher Young's modulus; and ordered structure, as measured by single-crystal X-ray diffraction. Recently, various photomechanical crystals with different motions (contraction, expansion, bending, fragmentation, hopping, curling, and twisting) are appearing at the forefront of smart materials research. The photomechanical motions of these single crystals during irradiation are triggered by solid-state photochemical reactions and accompanied by phase transformation. This Minireview summarizes recent developments in growing research into photoresponsive molecular crystals. The basic mechanisms of different kinds of photomechanical materials are described in detail; recent advances in photomechanical crystals for promising applications as smart materials are also highlighted.     

Recent advances in spherical photonic crystals: Generation and applications in optics

Spherical photonic crystals (PCs), generated by assembly of monodisperse colloidal nanospheres in a spherical confined geometry, attract great attention recently owing to their potential applications in the fields of displays, sensors, optoelectronic devices, and others. Compared to their conventional film or bulk counterparts, the optical stop band of the spherical PCs is independent of the rotation under illumination of the surface of a fixed incident angle of the light, broadening their applications. In this paper, we will review recent advances in the field of spherical PCs including design, preparation and potential applications. Various preparation strategies for spherical PCs, including solvent-evaporation induced crystallization method, microfluidic-assisted approach, and others are outlined. Their applications based on the unique optical properties (such as photonic band gaps and structural colors) for sensing and displaying are then presented, followed by the perspective of this emerging field.     

Mechanical Effects of Elastic Crystals Driven by Natural Sunlight and Force

Flexible crystals that can capture solar energy and convert it into mechanical energy are promising for a wide range of applications such as information storage and actuators, but obtaining them remains a challenge. Herein, an elastic crystal of a barbiturate derivative was found to be an excellent candidate, demonstrating plastic bending behavior under natural sunlight irradiation. ¹H NMR and high-resolution mass spectrum data of microcrystals before and after light irradiation demonstrated that light-induced [2+2] cycloaddition was the driving force for the photomechanical effects. Interestingly, the crystals retained elastic bending even after light irradiation. This is the first report of flexible crystals that can be driven by natural sunlight and that have both photomechanical properties and elasticity. Furthermore, regulation of the passive light output direction of the crystals and transport of objects by applying mechanical forces and light was demonstrated.