手性无机纳米材料圆偏振发光的研究进展

手性无机纳米材料因为具有优异的光物理特性及广泛的应用价值而备受关注。通过采用手性配体对无机纳米材料的表面进行修饰或将无机纳米材料与手性模板进行组装获得的手性结构,可以与光子强烈作用引起偏振态的改变,产生圆偏振光(circularly polarized light, CPL)。从产生机理来讲,CPL主要包括圆偏振荧光和圆偏振散射,在一些情况下这两个机理是共存的。本文总结了硫族半导体纳米材料、金属纳米团簇、钙钛矿、镧系配合物及其他复合纳米材料中CPL的研究进展。此外,还讨论了不同的手性无机纳米材料中CPL的主要来源。本综述得出的结论有望在分子水平上实现对CPL活性材料的各向异性因子进行调控,促进其在量子计算、光学数据存储、信息加密、3D显示器和光学传感等多个领域的发展。     

有机共晶光电功能材料与器件

在双组分或多组分有机共晶中,特殊的分子堆积方式和聚集态结构以及不同组分之间的协同和集合效应,使得有机共晶不仅保留了单一组分的固有属性,而且展现出更多新颖的宏观光电性质,在电导、铁电、双极性电荷传输、光响应、发光和给受体组分间电荷转移过程等方面具有重要的研究价值和应用前景,为有机单晶器件的高性能化和多功能化发展提供了新途径。因此,有机共晶的制备和性能研究逐渐成为近年来的热点。在本文中我们首先详细地介绍了有机共晶的分类情况,根据形成晶体的作用力分为电荷转移晶体、通过π-π相互作用形成的晶体和以分子间氢键、卤键相互作用为主的晶体;其次,以经典的7,7,8,8-四氰基对苯二醌二甲烷（TCNQ）、1,2,4,5-苯四甲腈（TCNB）和富勒烯（C₆₀）三种典型的受体分子为例,列举了常见的有机给受体材料;再次,介绍了8种制备有机共晶的常用方法,讨论了有机共晶中分子排布方式对性能的影响;最后,介绍了有机共晶在光电器件中的应用。我们相信有机共晶的理论和应用研究会进一步丰富和推动有机晶体材料和光电子学领域的发展。     

圆偏振光在手性聚合物合成与结构调控中的应用

手性是自然界中普遍存在的有趣现象之一,在生命体中手性大分子特有的不对称结构在维持生命过程、新陈代谢和进化等面均起着决定性作用.受此启发,合成具有新型结构的光学活性聚合物,研究其独特的物理化学性质和功能已成为当今高分子领域研究的热点.左旋和右旋的圆偏振光已被广泛应用于氨基酸衍生物的不对称光合成、光分解和去消旋化反应,以及诱导含有偶氮苯或三苯胺等特定功能基团的超分子组装体或无机纳米粒子形成稳定螺旋结构.本文详细地介绍了圆偏振光辐照在手性聚合物合成与螺旋结构调控中的应用,初步揭示了圆偏振光的作用机制以及优势,归纳总结了已取得的研究进展,并对圆偏振光在手性聚合物合成与结构调控中的应用及发展进行了简单的评述和展望.     

手性有机小分子圆偏振发光的研究进展

圆偏振发光不仅能直观地反映手性发光体系的激发态结构信息,而且在3D显示、自旋信息通讯、信息存储与处理、CPL激光、生物探针等领域具有广泛的应用前景.因此,近年来圆偏振发光材料引起了人们越来越多的兴趣与关注,成为有机发光功能材料领域一个新的研究热点.本综述总结近年来关于手性有机小分子圆偏振发光的研究进展,主要围绕具有中心手性、轴手性、面手性和螺旋手性的圆偏振发光有机小分子展开介绍.     

圆偏振热活化延迟荧光材料及其器件的研究进展

圆偏振热活化延迟荧光材料具有分子结构易修饰、激子利用率高及圆偏振发光等特点,在光学信息存储、3D显示、发光器件和数据加密等领域具有广阔应用前景.利用此类材料作为发光层制备的圆偏振有机发光二极管,能够同时实现高发光不对称因子和理论上达100%的激子利用率,对发展低功耗和高性能有机发光二极管至关重要.近年来,通过不断的分子结构设计与优化,该类材料在有机发光二极管中的电致发光效率不断提高,但是仍然存在不对称因子低及效率滚降严重等问题.基于此,整理了目前已报道的圆偏振热活化延迟荧光化合物,重点讨论了其分子结构设计与光物理性质、圆偏振特性以及电致发光性能的关系规律,并对高性能圆偏振热活化延迟荧光材料的制备及其在有机发光二极管中的应用进行了展望.     

联萘基手性发光材料的圆偏振发光

本文综述了近年来基于联萘基结构的圆偏振发光材料的研究工作.从光致发光和电致发光两方面总结了不同体系下联萘基材料的圆偏振发光,为相关领域的研究者提供了设计思路,并对圆偏振发光材料的研究发展方向进行了展望.     

手性钙钛矿纳米材料的构筑及光电性能

金属卤化物钙钛矿纳米材料因其丰富的化学结构和优异的光电性能,已成为一种极具应用前景的半导体材料。在钙钛矿无机框架中引入有机手性分子后,能够比较容易地得到手性钙钛矿纳米材料,从而可以极大地推动智能光电材料和自旋电子器件的快速发展。本文将综述手性钙钛矿纳米材料的构筑与手性产生机理的最新研究进展,包括一维手性钙钛矿纳米线、二维及准二维手性有机-无机杂化钙钛矿纳米片、三维手性钙钛矿纳米晶、超分子组装体系中诱导的手性钙钛矿纳米晶等。值得注意的是,不同种类的手性钙钛矿纳米材料在圆二色性、圆偏振发光、铁电性、自旋电子学等方面展现出优异的光电性能及巨大的应用前景。但是,有关手性钙钛矿纳米材料的研究目前还处于初级阶段,其中很多机理还存在争议,许多基础性和应用型的工作也有待开展。     

火星探测和天体矿物手性

从地球到月球到火星,人类一直没有停下探矿寻宝的脚步。从冰洲石到水晶到紫水晶,这些晶莹剔透矿石所呈现的光学现象给科学家带来“光是什么”和“手性起源”的百折不挠探究,贯穿整个科学发展史,促进科学、技术和现代社会进步,并将持续为未来科技发展带来不可估量的影响。     

基于八氢联萘酚的大位阻手性发光材料构建及光电性质研究

以手性发光材料为发光中心制备能够直接发射出圆偏振电致发光(circularly polarized electroluminescence, CPEL)的器件, 即CP-organic light-emitting diode (CP-OLED), 在3D显示领域有极大的应用前景. 本工作设计了基于八氢联萘酚的手性热激活延迟荧光材料(S/R)-OBN-tBuCz, 八氢联萘酚作为有效的手性源, 而叔丁基咔唑取代的氰基苯作为高效发光部分. 八氢联萘酚外围较多的氢原子以及较大的叔丁基可以有效增加手性发光分子的空间位阻, 降低堆积效应, 抑制浓度淬灭, 有效提升器件的发光效率. 所合成的手性发光材料展现出明亮的绿光发射(523 nm)、高的荧光量子产率(85.2%)、较小的单线态-三线态能级差ΔE_ST (0.05 eV)和优秀的热稳定性. 圆二色(CD)与圆偏振发光(CPL)光谱显示出明显的对称圆偏振发光信号, 且溶液中的g_PL为+8.6×10^-4和–6.5×10^-4. 基于(S/R)-OBN-tBuCz的电致发光器件表现出优异性能: 起亮电压为3.9 V, 最大亮度为27709 cd•m^-2, 最大电流效率为43.8 cd•A^-1, 最大功率效率为33.5 lm•W^-1, 最大外量子效率为12.4%, 效率滚降很低, 并显示出明显的圆偏振电致发光信号, g_EL分别为+1.57×10^-3和–0.90×10^-3. 大位阻手性发光材料的设计有助于实现高效的CP-OLED, 该研究能促进手性发光材料及圆偏振电致发光器件等相关研究领域的发展.     

Circularly Polarized Light Triggers Biosensing Based on Chiral Assemblies

Chiral assemblies have attracted great interest because of their many potential applications, such as in chiral sensing, asymmetric catalysis, and optical devices. Here, by using specific DNAzymes, a chiral core–satellite assembly consisting of a DNAzyme-driven spiny nanorod dimer core and upconversion nanoparticle (UCNP) satellite was constructed. The chirality of this assembly originates from the geometry chirality. This chiral assembly can be used as a photothermally activated probe for the simultaneous detection of multiple analytes in living cells. Under illumination with 980 nm left circularly polarized (LCP) light, this probe was used to quantify and visualize intracellular metal ions.     

Circularly Polarized Luminescence from Simple Organic Molecules

This article aims to show the identity of “circularly polarized luminescent active simple organic molecules” as a new concept in organic chemistry due to the potential interest of these molecules, as availed by the exponentially growing number of research articles related to them. In particular, it describes and highlights the interest and difficulty in developing chiral simple (small and non‐aggregated) organic molecules able to emit left‐ or right‐circularly polarized light efficiently, the efforts realized up to now to reach this challenging objective, and the most significant milestones achieved to date. General guidelines for the preparation of these interesting molecules are also presented.     

Solid-State Near-Infrared Circularly Polarized Luminescence from Chiral YbIII-Single-Molecule Magnet

A field-induced chiral Yb^III Single-Molecule Magnet (SMM) displayed an unprecedented near-infrared circularly polarized luminescence (NIR-CPL) in the solid-state. The bridging bis(1,10-phenantro[5,6b])tetrathiafulvalene triad ( L ) allowed an efficient sensitization of the NIR ²F_5/2→²F_7/2 emission while the NIR-CPL is associated to the f-f transitions of the Yb^III ion bearing chiral β-diketonate derived-camphorate ancillary ligands.     

Multiply Twisted Chiral Macrocycles Clamped by Tethered Binaphthyls Exhibiting High Circularly Polarized Luminescence Brightness

Chiral macrocyclic dimers, trimers, and tetramers composed of paraphenylene and tethered binaphthyl were synthesized, and their molecular structures and chiroptical properties were investigated. X-ray analysis and theoretical calculations revealed that multiple twisted molecular structures – dimers, trimers, and tetramers – adopt figure-of-eight, Möbius triangle, and concave rectangle structures, respectively. These homologues have large ϵ values in their UV-vis absorption spectra because of the π-conjugation of the naphthalene-phenylene-naphthalene frameworks. Owing to the shape-persistent ring structure and tethering with −OCH₂CH₂O−, high fluorescence quantum yields and a relatively high dissymmetry factor g_CPL in circularly polarized luminescence (CPL) spectra were achieved. This results in CPL brightness (B_CPL) of over 100, which is greater than that of the conventional organic CPL dye.     

Chiral Oligothiophenes with Remarkable Circularly Polarized Luminescence and Electroluminescence in Thin Films

This work reports the first observation of circularly polarized electroluminescence (CPEL) in thin films of self-organized oligothiophenes. Four new 1,4-phenylene and 9H-carbazole-based oligothiophenes were ad hoc designed to ensure efficient spontaneous formation of chiral supramolecular order. They were easily synthesized and their chiroptical properties in thin films were measured. Circularly polarized luminescence (CPL) spectra revealed g_lum in the order of 10⁻² on a wide wavelengths range, originating from their self-organized chiral supramolecular organization. These molecules have reasonable properties as organic semiconductors and for this reason they can constitute the active layer of circularly-polarized organic light-emitting diodes (CP-OLEDs). Thus, we could investigate directly their electroluminescence (EL) and CPEL, without resorting to blends, but rather in a simple multilayer device with basic architecture. This is the first example of a CP-OLED with active layer made only of a small organic compound.     

Discriminating Chiral Supramolecular Motions by Circularly Polarized Luminescence

Molecular motions are closely associated with the behaviors and properties of organic materials. However, monitoring molecular motions is challenging. Herein, a chiral supramolecular system consisting of L-/D-phenylalanine (LPF/DPF) as a chiral inducer and an achiral tetraphenylethene derivative (TPEF) as a molecular rotor has been proposed and explored for real-time discriminating the supramolecular motions by the visualization of circularly polarized luminescence (CPL) signal variations. Derived from the ordered molecular motions of TPEF induced by LPF/DPF, highly organized aggregates have been progressively assembled in a controlled manner with differentiated morphologies, including spherical particles, one-dimensional fibers, and floor-shaped supercrystals. Notably, increasing level of ordered aggregates, in turn, led to quenching emissions, while the CPL signals have been dramatically amplified accompanying by a sharp enhancement of luminescence dissymmetry factors (g_lum) from nearly 0 to −0.1. The significant amplification of CPL is attributed to the ordered aggregates of supramolecules, leading to the decrease of electric transition dipole moments in supramolecular system. As a result of the chiral supramolecular motions powered by supramolecular crystallization, the supramolecular motions are conveniently discriminated by visual CPL signal variation with an enhancement of g_lum value from 0 to −0.1 in real time.     

圆偏振发光性质的热活化延迟荧光材料及电致发光器件

具有圆偏振发光性质的热活化延迟荧光(circularly polarized thermally activated delayed fluorescence,CP-TADF)材料,因其在数据存储、生物成像以及3D显示等领域的应用前景,受到学者们的广泛关注。基于此类材料所制备的圆偏振热活化延迟荧光器件展现出优异的器件性能。本文从圆偏振热活化延迟荧光材料的发光机理及分子设计策略出发,依据CP-TADF材料构筑方法的不同,概括了其结构设计策略,系统地综述了各种类型CP-TADF材料的分子结构和光电性能的关系及其在电致发光器件领域的应用,最后探讨了目前CP-TADF材料存在的问题,并展望了其未来发展前景及挑战。     

Near Infared Circularly Polarized Luminescence From Water Stable Organic Nanoparticles Containing a Chiral Yb(III) Complex

We report the first example of very efficient NIR Circularly Polarized Luminescence (CPL) (around 970 nm) in water, obtained thanks to the combined use of a chiral Yb complex and of poly lactic-co-glycolic acid (PLGA) nanoparticles. [Yb L (tta)₂]CH₃COO ( L =N, N’-bis(2-pyridylmethylidene)-1,2-(R,R+S,S) cyclohexanediamine and tta=2-thenoyltrifluoroacetonate) shows good CPL in organic solvents, because the tta ligands efficiently sensitize Yb NIR luminescence and the readily prepared chiral ligand L endows the complex with the necessary dissymmetry. PLGA nanoparticles incorporate the complex and protect the metal ion from the intrusion of solvent molecules, while ensuring biocompatibility, water solubility and stability to the complex. Hydrophilic NIR-CPL optical probes can find applications in the field of NIR-CPL bio-assays.