手性超分子凝胶材料的研究进展

超分子凝胶作为一类新型的智能自组装软材料,从分子水平到微纳米水平的组装过程中,手性发挥了重要的作用.一般情况下,手性信号都是直接从分子转换到纳米纤维中,但也有一些有趣的现象,即混合两种对映体可以调控得到不同手性形态的纤维结构,甚至一些本身不具备手性的构筑块同样可以通过外界诱导得到具有手性结构的组装体.对纤维手性自组装机理的研究不仅揭示了分子手性到纤维微纳米手性转换这一重要过程,而且对新型的手性材料和微纳米器件的开发也有启发作用.有关微纳米水平的手性材料在手性识别、不对称催化、生物大分子结晶和无机材料的手性模板剂、生物医用等领域的应用研究也逐渐得到重视.主要综述了近二十年来有关手性超分子凝胶的研究,主要从凝胶因子的手性自组装、手性在分子水平和微纳米水平上的形貌调控和表征方法、超分子凝胶的手性应用几个方面进行概述,并对手性超分子凝胶的应用和研究前景进行了展望.     

卟啉-多肽超分子组装体系的研究进展

近年来,卟啉-多肽的超分子组装体系的研究受到了国内外学者的广泛关注,已成为超分子化学、生物材料科学研究的前沿领域之一。卟啉-多肽超分子组装体系因具有结构和功能多样化以及良好的生物相容性等优点,在生物传感、药物治疗、分子识别和光电器件等方面展示出巨大的应用潜力。文章综述了卟啉和多肽超分子构筑模块的分子结构设计、组装体的形貌调控、组装体应用3个方面的主要研究进展,介绍了卟啉与多肽分子之间的主要非共价作用方式,包括分子间静电相互作用、氢键、配位键、亲水/疏水性等,分析了该领域当前研究的焦点及亟需解决的问题。     

小分子硼酸肽的自组装

利用FMOC化学固相多肽合成法合成了3种含精氨酸的小分子硼酸肽(标记为BPs(1-3))。在生理pH下,含阳离子的硼酸肽可自组装形成有序超分子纳米组装体。二羟基酚染料茜素红与硼酸肽可特异性结合形成五元环硼酸酯,伴随荧光和颜色的显著变化,可进一步调控硼酸肽的自组装行为。通过扫描电镜研究茜素红调控前后硼酸肽的自组装形态,并用红外光谱和圆二色谱研究其自组装机理。结果表明,3种含精氨酸硼酸肽在生理pH下可自组装形成不同的超分子纳米组装体。通过茜素红的调控,茜素红/硼酸肽化合物,可自组装形成更有序,更精致的超分子聚集体。     

有机光电子与分子工程教育部重点实验室

有机光电子与分子工程教育部重点实验室（以下简称实验室）依托于清华大学化学系,以化学为基础、以分子工程学为手段,以发展新型有机光电功能材料和器件为目标,重点发展跨化学、化工、材料、信息及能源等领域的有机光电子学和分子工程学的理论和实践。实验室自2003年11月成立以来,在新型有机电致发光分子、两亲性分子、生物分子修饰的共轭分子、光致变色光敏分子、功能梳形共聚物分子、纳米晶和光子晶体的合成制备及其在新型有机平板显示器、有机场晶体管、有机光耦器件、有机太阳能电池、三阶非线性全光开关、新型锂电池、燃料电池中的应用等方向均取得了显著的成绩;发展了纳米晶催化、原子经济反应和绿色合成化学等新方向,丰富了有机光电子理论和分子工程学理论;在全面解决材料设计与合成、器件制备与封装、屏体的驱动和老炼等关键技术的基础上,建成了我国第一条OLED大规模生产线．实现了OLED屏及模块的批量生产和销售,其中高可靠性OLED显示屏已成功应用于“神七”舱外航天服上。     

基于硅基自组装膜的分子电子器件

文章综述了以硅为基底的自组装有机单层膜在分子电子器件中的应用,重点介绍了自组装膜的电子传导性,包括各种理论模型,如隧穿效应、热电子激发、Poole-Frankel激发以及跨越传导。此外,以烷基链(σ-分子),共轭链(π-分子)体系组成的自组装膜为基础的各种分子电子器件,如二极管、共振隧穿二极管,分子记忆和分子晶体管的概念、结构及工作原理也一并被讨论。     

有机分子导线的合成及其导电性质研究

主要结合分子导线的电子传导性对有机线性分子的制备方法进行了论述.共价键合法具有形貌和电子传递的可控性,但合成及纯化的困难限制了其进一步发展;自组装法尽管存在着结构缺陷,而且,目标线性分子的直径和维度也难以控制,但其制备方法简单、灵活,所以是有机分子导线的主要研究方向.以白组装法为基础,通过分子间弱的相互作用、定向原子堆积、配位键等发展了新的有机线性分子建构方法.目前,在微纳电子器件应用中,有机线性材料尽管很难与无机材料竞争,但其作为无机材料的补充,也展示了良好的应用前景.     

基于[4-[(N-(2-巯基乙基),N''''-甲基)胺基]苯基]三氰基乙烯(TAPE)的分子整流器

制备了含巯基的共轭有机分子-[4-[(N-(2-巯基乙基),N'-甲基)胺基]苯基]三氰基乙烯(TAPE),以分子自组装方法制作了结构为"Au/ TAPE /Au(纳米颗粒)"的分子整流器件.用扫描隧道显微镜(STM)测试了该器件的电流-电压(I-V)性质,在偏压为±0.95V时,有最高整流比为22.7;考察了顶电极制备工艺前、后单分子膜的电性能.用掠角反射红外光谱对单分子有机层进行了表征.     

卟啉纳米结构合成获进展 有望提升燃料电池性能

中科院长春光机所发光学及应用国家重点实验室（筹）研究员孙再成与河南大学教育部特种功能材料实验室教授白峰合作,研究了卟啉分子在表面活性剂辅助下的自组装问题。研究表明,卟啉分子可以自组装成从纳米线、纳米短棒到八面体的纳米颗粒。     

分子与纳米自组装材料的研究进展

对近年来分子与纳米自组装材料方面的研究进行了总结，分别从小分子自组装，大分子自组装，纳米自组装三个方面进行综述，展示了该领域的一些重要进展和研究结果的应用前景。     

纳米结构太阳能电池材料的研究进展

纳米结构材料是当今科学研究的热点,它应用于太阳能电池具有成本低、稳定性好、光电转化率高等特点.介绍了纳米结构材料,如自组装纳米结构的有机盘状液晶太阳能电池和无机纳米晶太阳能电池材料(主要包括敏化TiO2纳米晶、CdSe和CdTe纳米晶、Si基纳米结构)的研究和应用进展,并展望了这些纳米结构材料作为太阳能电池材料的未来发展.     

From Single Molecules to Thin Film Electronics,Nanofibers, e‐Textiles and Power Cables: Bridging Length Scales with Organic Semiconductors

Organic semiconductors are the centerpiece of several vibrant research fields from single‐molecule to organic electronics, and they are finding increasing use in bioelectronics and even classical polymer technology. The versatile chemistry and broad range of electronic functionalities of conjugated materials enable the bridging of length scales 15 orders of magnitude apart, ranging from a single nanometer (10^?9 m) to the size of continents (10⁶ m). This work provides a taste of the diverse applications that can be realized with organic semiconductors. The reader will embark on a journey from single molecular junctions to thin film organic electronics, supramolecular assemblies, biomaterials such as amyloid fibrils and nanofibrillated cellulose, conducting fibers and yarns for e‐textiles, and finally to power cables that shuffle power across thousands of kilometers.     

Switching Colloidal Superstructures by Critical Casimir Forces

Recent breakthroughs in colloidal synthesis promise the bottom‐up assembly of superstructures on nano‐ and micrometer length scales, offering molecular analogues on the colloidal scale. However, a structural control similar to that in supramolecular chemistry remains very challenging. Here, colloidal superstructures are built and controlled using critical Casimir forces on patchy colloidal particles. These solvent‐mediated forces offer direct analogues of molecular bonds, allowing patch‐to‐patch binding with exquisite temperature control of bond strength and stiffness. Particles with two patches are shown to form linear chains undergoing morphological changes with temperature, resembling a polymer collapse under poor‐solvent conditions. This reversible temperature switching carries over to particles with higher valency, exhibiting a variety of patch‐to‐patch bonded structures. Using Monte Carlo simulations, it is shown that the collapse results from the growing interaction range favoring close‐packed configurations. These results offer new opportunities for the active control of complex structures at the nano and micrometer scale, paving the way to novel temperature‐switchable materials.     

Supramolecular Helices: Chirality Transfer from Conjugated Molecules to Structures

Different scales of chirality endow a material with many excellent properties and potential applications. In this review, using π‐conjugated molecules as functional building blocks, recent progress on supramolecular helices inspired by biological helicity is summarized. First, induced chirality on conjugated polymers and small molecules is introduced. Molecular chirality can be amplified to nanostructures, superstructures, and even macroscopic structures by a self‐assembly process. Then, the principles for tuning the helicity of supramolecular chirality, as well as formation of helical heterojunctions, are summarized. Finally, the potential applications of chiral structures in chiral sensing and organic electronic devices are critically reviewed. Due to recent progress in chiral structures, an interdisciplinary area called “chiral electronics” is expected to gain wide popularity in the near future.     

Supramolecular Chiroptical Switches Based on Achiral Molecules

Chirality plays an important role in biological and material sciences. By introducing chiral elements into functional materials, new properties are created and an increase in information density can be achieved. Chiral properties of functional materials do not only rely on molecular structure, but also on supramolecular interaction between the building blocks. In contrast to the generally accepted opinion that chiral systems should include chiral molecules, this Research News introduces the role of achiral molecules in realizing chiral properties in films and gel‐like materials. Even a system that is entirely composed of achiral molecules can exhibit interesting chiroptical properties in supramolecular ultrathin films. This article demonstrates how achiral molecules can be assembled into supramolecular chiral films and organogels. It further shows how the incorporated achiral molecules can be used to switch the chiral properties of these supramolecular films and organogels.     

Easy‐to‐clean Schichten – spezielle Anwendungen

Easy to clean surfaces – special applications Easy to clean surfaces can be made by wet‐chemical coating with subsequent heat‐treatment. Organically modified metal oxide films form the base reinforced by nano composite structures. The hydro‐ and oleophobic effect is obtained by perfluorinated organic molecule chains in the nano composite sol‐gel coatings. Application specific materials can be synthesized by the proper choice of suitable starting compounds and process parameters. The resulting coatings consist of a three‐dimensional cross‐linked inorganic part (such as a silica network) combined with an organic part. The organic material acts either as a surface modifier (example: alkyl, phenyl) or as crosslinker (example: acrylic, epoxy). The properties of such coating systems can be adjusted to obtain a wide range of glass‐ceramic or polymer‐like properties. The incorporation of nanoparticles into these materials significantly enhances the abrasion and the scratch resistance. Such coatings mainly on metal parts are used in diagnostics, analytical chemistry and medical technology.     

Highly Efficient and Tunable Filtering of Electrons' Spin by Supramolecular Chirality of Nanofiber-Based Materials

Organic semiconductors and organic–inorganic hybrids are promising materials for spintronic-based memory devices. Recently, an alternative route to organic spintronic based on chiral-induced spin selectivity (CISS) is suggested. In the CISS effect, the chirality of the molecular system itself acts as a spin filter, thus avoiding the use of magnets for spin injection. Here, spin filtering in excess of 85% in helical π-conjugated materials based on supramolecular nanofibers at room temperature is reported. The high spin-filtering efficiency can even be observed in nanofibers assembled from mixtures of chiral and achiral molecules through chiral amplification effect. Furthermore and most excitingly, it is shown that both “up” and “down” orientations of filtered spins can be obtained in a single enantiopure system via the temperature-dependent helicity (P and M) inversion of supramolecular nanofibers. The findings showcase that materials based on helical noncovalently assembled systems are modular platforms with an emerging structure–property relationship for spintronic applications.     

Photoswitching and Thermoresponsive Properties of Conjugated Multi‐chromophore Nanostructured Materials

Conjugated multi‐chromophore organic nanostructured materials have recently emerged as a new class of functional materials for developing efficient light‐harvesting, photosensitization, photocatalysis, and sensor devices because of their unique photophysical and photochemical properties. Here, we demonstrate the formation of various nanostructures (fibers and flakes) related to the molecular arrangement (H‐aggregation) of quaterthiophene (QTH) molecules and their influence on the photophysical properties. XRD studies confirm that the fiber structure consists of >95% crystalline material, whereas the flake structure is almost completely amorphous and the microstrain in flake‐shaped QTH is significantly higher than that of QTH in solution. The influence of the aggregation of the QTH molecules on their photoswitching and thermoresponsive photoluminescence properties is revealed. Time‐resolved anisotropic studies further unveil the relaxation dynamics and restricted chromophore properties of the self‐assembled nano/microstructured morphologies. Further investigations should pave the way for the future development of organic electronics, photovoltaics, and light‐harvesting systems based on π‐conjugated multi‐chromophore organic nanostructured materials.     

Patterning of Lyotropic Chromonic Liquid Crystals by Photoalignment with Photonic Metamasks

Controlling supramolecular self‐assembly in water‐based solutions is an important problem of interdisciplinary character that impacts the development of many functional materials and systems. Significant progress in aqueous self‐assembly and templating has been demonstrated by using lyotropic chromonic liquid crystals (LCLCs) as these materials show spontaneous orientational order caused by unidirectional stacking of plank‐like molecules into elongated aggregates. In this work, it is demonstrated that the alignment direction of chromonic assemblies can be patterned into complex spatially‐varying structures with very high micrometer‐scale precision. The approach uses photoalignment with light beams that exhibit a spatially‐varying direction of light polarization. The state of polarization is imprinted into a layer of photosensitive dye that is protected against dissolution into the LCLC by a liquid crystalline polymer layer. The demonstrated level of control over the spatial orientation of LCLC opens opportunities for engineering materials and devices for optical and biological applications.     

25th Anniversary Article: Design of Polymethine Dyes for All‐Optical Switching Applications: Guidance from Theoretical and Computational Studies

All‐optical switching—controlling light with light—has the potential to meet the ever‐increasing demand for data transmission bandwidth. The development of organic π‐conjugated molecular materials with the requisite properties for all‐optical switching applications has long proven to be a significant challenge. However, recent advances demonstrate that polymethine dyes have the potential to meet the necessary requirements. In this review, we explore the theoretical underpinnings that guide the design of π‐conjugated materials for all‐optical switching applications. We underline, from a computational chemistry standpoint, the relationships among chemical structure, electronic structure, and optical properties that make polymethines such promising materials.     

Cyclodextrin-threaded conjugated polyrotaxanes as insulated molecular wires with reduced interstrand interactions

Control of intermolecular interactions is crucial to the exploitation of molecular semiconductors for both organic electronics and the viable manipulation and incorporation of single molecules into nano-engineered devices. Here we explore the properties of a class of materials that are engineered at a supramolecular level by threading a conjugated macromolecule, such as poly(para-phenylene), poly(4,4'-diphenylene vinylene) or polyfluorene through alpha- or beta-cyclodextrin rings, so as to reduce intermolecular interactions and solid-state packing effects that red-shift and partially quench the luminescence. Our approach preserves the fundamental semiconducting properties of the conjugated wires, and is effective at both increasing the photoluminescence efficiency and blue-shifting the emission of the conjugated cores, in the solid state, while still allowing charge-transport. We used the polymers to prepare single-layer light-emitting diodes with Ca and Al cathodes, and observed blue and green emission. The reduced tendency for polymer chains to aggregate allows solution-processing of individual polyrotaxane wires onto substrates, as revealed by scanning force microscopy.