有机发光晶体管的关键材料和器件研究※

有机发光晶体管(organic light-emitting transistor, OLET)是一种变革性的小型化有机光电器件, 其在同一器件中集成了场效应晶体管和发光二极管的两种器件功能, 在材料的基础物性研究、新型柔性显示/照明、有机电泵浦激光以及片上集成光电子器件等方面都具有着重要的研究意义. OLET独特的器件结构及工作模式使其对核心的关键材料和器件制备提出了新的要求, 而高性能OLET器件的构筑需要从材料和器件两个方面同时进行优化与改善. 近五年作者课题组和合作者在全面调研和分析OLET领域整体研究背景和存在基本科学问题基础上, 聚焦于高迁移率发光有机半导体关键材料的开发和高效OLET器件(线光源和面光源发光模式)的构筑两个方面开展了初步的探索性研究, 发展了系列特别是基于蒽和芴的高迁移率发光/激光有机半导体材料, 构筑了高性能的单组分有机单晶OLET器件和新型平面OLET面光源发射显示器件, 为进一步推动OLET及其相关领域发展奠定了重要的材料和器件研究基础.     

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.     

基于苯乙烯和苯并噻二唑共聚场效应发光高分子材料的设计合成及性能研究

共轭高分子材料由于其优异的光电性能和可溶液加工等特性在有机光电器件中具有重要应用.本工作采用Stille偶联和Suzuki聚合反应,合成了两个由经典发光基元苯乙烯片段和共轭吸电子结构基元苯并噻二唑共聚的高分子材料聚（1,2-双（2,5-双（异辛氧基）亚苯基亚乙烯基-2,1,3-苯并噻二唑））（PVBT）和聚（1,2-双（2,5-双（正辛氧基）亚苯基亚乙烯基-2,1,3-苯并噻二唑））（nPVBT）.通过凝胶渗透色谱（GPC）、元素分析及差式扫描量热法（DSC）对PVBT和nPVBT两种高分子材料的结构及热稳定性进行表征,结果表明它们均具有良好的热稳定性,分解温度约380℃.由于烷氧基链的存在,两个材料具有良好的溶解性及成膜加工性.PVBT和nPVBT均表现出优异的发光特性,最大发射波长在590~605 nm范围,溶液下荧光量子产率为23%~35%,固态薄膜下量子产率为12%~20%.以这两个高分子材料薄膜作为活性层,所制备的顶栅-底接触型有机场效应晶体管器件显示出典型的p型电荷传输性能,空穴迁移率可达1.1×10^-4 cm²·V^-1·s^-1,开关比为10³~10⁴.本研究为发展高性能光电集成高分子材料提供了新思路,有望推动有机光电集成器件的研究.     

二苯乙烯基蒽聚集诱导发光材料体系的研究进展

具有聚集诱导发光(AIE)性质的有机荧光分子由于其扭曲的分子构型,在聚集态或固态表现出显著增强的荧光发射,避免了传统有机荧光分子的浓度猝灭现象,因而在光电器件、生物传感等领域有着广泛的应用.本文着重介绍了具有AIE性质的二苯乙烯基蒽(DSA)衍生物及其在高效固态发光材料、刺激响应材料、生物成像和生物与化学传感等领域的研究进展.     

高分子发光材料研究进展

高分子发光材料具有可溶液加工的特点,适于制备低成本、大面积发光器件,在平板显示和固体照明领域具有潜在的应用前景.近年来,高分子发光材料在发光机制、材料体系和器件性能等方面均取得了重要进展,各项性能得到了大幅度提升.本文从材料和器件角度,围绕高分子荧光材料、高分子磷光材料和高分子热活化延迟荧光材料的分子设计策略,总结和评述了高分子荧光材料的颜色调控和效率提升途径,高分子磷光材料的磷光掺杂剂、高分子主体、拓扑结构等因素对发光性能的影响规律,以及高分子热活化延迟荧光材料的设计原理和典型材料体系.同时,分析了高分子发光材料未来发展面临的机遇和挑战.     

蓝光热激活延迟荧光分子设计策略概述

热激活延迟荧光（thermally activated delayed fluorescence,TADF）分子由于三重态上的激子可以通过反向系间窜越到单重态并辐射发出荧光，因此在有机发光二极管（organic lightemitting diode, OLED）中理论上可以实现100%的激子利用率。具有TADF特性的发光材料融合了第一代荧光材料和第二代磷光材料的优点，不仅可以实现100%的内量子效率，还有助于降低器件的材料成本，被誉为第三代OLED发光材料，并成为突破高效稳定蓝光OLED瓶颈的潜在解决方案。本文从发光机理出发，系统阐述了高效稳定蓝光TADF分子的设计策略，包括高荧光量子产率、短延迟荧光寿命、窄发射光谱半峰宽、显著的水平分子取向和良好的光电稳定性等。本文旨在为高性能蓝光TADF分子的开发提供理论支持。最后，总结了当前蓝光TADF材料存在的问题，并对其未来的发展前景进行了展望。     

《化学通报》网络版(Chemistry Online)2005年第11期论文摘要

[w123]具有纳米结构的有机发光材料研究进展**Progress in Research on Organic Nanomaterials for Luminescence赵雷黄维*(复旦大学先进材料研究院上海200433)对有机纳米发光材料制备方法以及材料的性能作了较为全面的综述。有机纳米发光材料由于存在分子间作用力(范德华力)或氢键以及具有小的Frenkel激子半径,与无机半导体纳米微粒以及纳米金属有着很大的区别,具有自己独特的光电性能,同时又兼具了有机发光材料响应速度快、可进行分子设计和纳米材料的尺寸效应等优点,在新型光电器件方面具有潜在应用前景。综合研究现状,本文也提出了该…     

金属配合物在有机太阳电池中的应用进展

有机太阳电池因具有质量轻、色彩丰富及可制备柔性大面积器件等优势而备受关注.开发高性能的活性层给、受体材料及界面层材料是提升有机太阳电池光电性能的关键.金属配合物兼具金属配位的自组装有序性和有机分子的结构多样性,且具有较高的三线态激子密度和较长的激子寿命,是一类重要的光电功能材料.随着对不同金属配合物光电性质的不断研究,越来越多的金属配合物光电材料被应用于有机太阳电池中,并获得了较高的器件光电性能.本文综述了基于铂、锌、铱、钌、锆等金属的配合物在有机太阳电池活性层、界面层及添加剂中的应用,并对其结构-性能关系进行了深入分析,最后对这类材料面临的挑战与机遇进行了展望,以便为高性能金属配合物材料的设计及其在有机太阳电池中的应用提供参考与启发.     

含芳胺和1,3,4-噁二唑的星型有机分子合成及光电性质

通过分子设计, 采用多步反应合成了2种新型的具有“双极”(Bipolar)性质和发光性能的以N原子为中心的星型有机分子. 用1H NMR, MS和元素分析进行了表征, 研究了化合物的热稳定性和固体粉末的光致发光性质, 并用循环伏安法测定了其电化学性能. 结果表明, 这种同时具备空穴传导和电子输入双重功能基团的星型有机小分子的光致发光性能优良(量子效率达到82%—95%), 热稳定性好, 可以作为有机电致发光器件材料.     

荧光/磷光混合型白光有机发光二极管的研究

白光有机发光二极管（white organic light-emitting diodes,WOLEDs）在全色显示、固态照明以及背光源等领域有巨大的应用前景,其研究备受关注.其中,荧光/磷光混合型WOLEDs因兼具荧光材料的长寿命和磷光材料的高效率,被认为是目前最有希望实现照明应用的器件结构.荧光/磷光混合型WOLEDs最重要的问题是要解决荧光材料的单线态激子和磷光材料的三线态激子的协同发光.为了避免单线态激子和三线态激子的相互猝灭问题,必须设计有效的器件结构.本文以两种不同三线态能级的蓝光荧光材料为研究对象,介绍了不同高性能荧光/磷光混合型WOLEDs的结构设计与性能.研究表明,载流子传输平衡的高效结构设计和激子分布宽范围内的有效调控是实现高性能荧光/磷光混合型WOLEDs的关键.     

Mild Synthesis of Polychlorinated Arenes for Efficient Organic Light-emitting Diodes with Dual Thermally Activated Delayed Fluorescence

Polychlorinated (hetero)arenes have shown great promise for organic optoelectronics applications. However, the harsh synthetic routes for polychlorinated compounds and the possible luminescence quenching from the compact intermolecular π–π stacking induced by chlorine atoms limit their investigations and applications in luminescent materials. Herein, two isomeric polychlorinated polycyclic aromatic hydrocarbon (PAH) compounds JY-1-Cl and JY-2-Cl consisting of rigidified aryl ketones and amine are designed and synthesized under mild conditions through nucleophilic chlorination intermediated by an electron donor-acceptor complex. Among them, as a result of the strong π–π interactions induced by chlorine atoms, JY-2-Cl exhibits bright monomer and dimer emissions with dual thermally activated delayed fluorescence (TADF) characters. Notably, compared with the non-chlorinated compounds, a high photoluminescence quantum yield is maintained after introducing multiple chlorine atoms into JY-2-Cl . The first dual-TADF organic light-emitting diodes are also successfully fabricated with maximum external quantum efficiency as high as 29.1 % by employing JY-2-Cl as emitter. This work presents a new paradigm and synthesis of polychlorinated amine-carbonyl PAHs and demonstrates the great potential of the chlorinated materials for luminescent applications.     

Organic Fluorophores Exhibiting Highly Efficient Photoluminescence in the Solid State

There has been extensive research on the development of organic optoelectronic devices, such as organic light‐emitting diodes, organic field‐effect transistors, and organic solid‐state lasers from various viewpoints, ranging from basic studies to practical applications. As organic materials are used as solids in these devices, the importance of organic chromophores that exhibit intense emissions of visible light in the solid state is greatly increasing in the field of organic electronics. However, highly efficient emission from organic solids is very difficult to attain because most organic emitting materials strongly tend to cause concentration quenching of the luminescence in the condensed phase. Therefore, in order to generate and improve organic optoelectronic devices, it is necessary to design novel chromophores that exhibit superior solid‐state emission performance. This Focus Review covers the recent development of highly emissive organic small molecules whose photoluminescence quantum yields in the solid state have been reported. Following the introduction, the photophysical processes of excited molecules are briefly reviewed. Subsequently, organic solid fluorophores are described with an emphasis on the characteristics of their molecular structures.     

Luminescent Ir(III) complexes containing benzothiazole-based tridentate ligands: synthesis, characterization, and application to organic light-emitting diodes

Ir(III) complexes that contain benzothiazole-based tridentate ligands were synthesized and their crystal structures and luminescent properties were examined. A neutral complex had a high quantum yield (89%) and performed well as an emissive material for organic light-emitting diodes.     

Non-Metal-Heteroatom-Doped Carbon Dots: Synthesis and Properties

Carbon dots (CDs) are new materials with applications in bioimaging, optical devices, catalysis, and many other fields. Their advantages, such as ease of large-scale preparation, low-costing precursors, highly tunable photoluminescence, satisfactory biocompatibility, and photostability against photobleaching, make them competitive alternatives to conventional semiconductor-based quantum dots and organic dyes. To overwhelm other luminescent materials in applications, their functionalities still need to be improved in spite of the abovementioned advantages. In recent years, it has been proven that heteroatom doping is an effective approach to improve the optical and electronic performance of CDs by tuning their carbon skeleton matrices and chemical structures. In this review, the development of non-metal-heteroatom-doped CDs, including heteroatom categories, preparation methods, and physicochemical properties, are discussed. Progressive trends in heteroatom-doped CDs are also discussed at the end of this review.     

荧光量子点的水相合成及其在化学和生物分析中的应用

荧光量子点(又称为半导体纳米晶体)是一种新兴的无机发光材料, 由于其具有独特的结构和光电性能, 在发光二极管、太阳能电池及生命科学等领域有广泛的应用. 目前, 有机相合成法和水相合成法已被成功地用于荧光量子点的合成. 与有机相合成法相比, 水相合成量子点方法简单、绿色且廉价, 合成的量子点水溶性好, 在生物医学等领域具有很好的应用前景. 本文主要介绍荧光量子点的水相合成方法及其在化学和生物分析中的应用, 并对其发展趋势进行了展望.     

Excited-State Dynamics of Non-Luminescent and Luminescent π-Radicals

Recently, the potential use of organic π-radicals and related spin systems has been expanded to modern technological applications. The unique excited-state dynamics of organic π-radicals can be useful to improve the stability of photochemically unstable organic compounds, make the polarization transfer applicable to information technology, and achieve effective up-conversion of interest for luminescence bioimaging, among others. Furthermore, highly luminescent stable π-radicals have been recently reported, which are especially interesting for application in organic light-emitting devices owing to their potential to provide an internal quantum efficiency of 100 %. Thus, the excited-state nature of stable π-radicals as well as the control of their excited-state spin dynamics are emerging topics both in terms of fundamental science and related technological applications. In this minireview, we focus on the excited-state dynamics of both photostable non(weakly)-luminescent and luminescent π-radicals, which are opposites of each other. In particular, we cover the following topics: 1) effective generation of high-spin photoexcited states and control of the excited-state dynamics by using non-luminescent π-radicals, 2) unique excited-state dynamics of luminescent π-radicals and radical excimers, and 3) applications utilizing excited-state dynamics of π-radicals.     

Cyan-Emitting Cu(I) Complexes and Their Luminescent Metallopolymers

Copper complexes have shown great versatility and a wide application range across the natural and life sciences, with a particular promise as organic light-emitting diodes. In this work, four novel heteroleptic Cu(I) complexes were designed in order to allow their integration in advanced materials such as metallopolymers. We herein present the synthesis and the electrochemical and photophysical characterisation of these Cu(I) complexes, in combination with ab initio calculations. The complexes present a bright cyan emission (λ_em ~ 505 nm) in their solid state, both as powder and as blends in a polymer matrix. The successful synthesis of metallopolymers embedding two of the novel complexes is shown. These copolymers were also found to be luminescent and their photophysical properties were compared to those of their polymer blends. The chemical nature of the polymer backbone contributes significantly to the photoluminescence quantum yield, paving a route for the strategic design of novel luminescent Cu(I)-based polymeric materials.     

A Novel Deep Blue LE-Dominated HLCT Excited State Design Strategy and Material for OLED

Deep blue luminescent materials play a crucial role in the organic light-emitting diodes (OLEDs). In this work, a novel deep blue molecule based on hybridized local and charge-transfer (HLCT) excited state was reported with the emission wavelength of 423 nm. The OLED based on this material achieved high maximum external quantum efficiency (EQE) of 4% with good color purity. The results revealed that the locally-excited (LE)-dominated HLCT excited state had obvious advantages in short wavelength and narrow spectrum emission. What is more, the experimental and theoretical combination was used to describe the excited state characteristic and to understand photophysical property.     

Efficient Circularly Polarized Electroluminescence from Achiral Luminescent Materials**

Circularly polarized electroluminescence (CP-EL) is generally produced in organic light-emitting diodes (OLEDs) based on special CP luminescent (CPL) materials, while common achiral luminescent materials are rarely considered to be capable of direct producing CP-EL. Herein, near ultraviolet CPL materials with high photoluminescence quantum yields and good CPL dissymmetry factors are developed, which can induce blue to red CPL for various achiral luminescent materials. Strong near ultraviolet CP-EL with the best external quantum efficiencies (η_exts) of 9.0 % and small efficiency roll-offs are achieved by using them as emitters for CP-OLEDs. By adopting them as hosts or sensitizers, commercially available yellow-orange achiral phosphorescence, thermally activated delayed fluorescence (TADF) and multi-resonance (MR) TADF materials can generate intense CP-EL, with high dissymmetry factors and outstanding η_exts (30.8 %), demonstrating a simple and universal avenue towards efficient CP-EL.     

Solvent-free Synthesis of Flowable Carbon Clusters with Customizable Size and Tunable Optical Performance

We propose a rapid and solvent-flee route for synthesizing luminous carbon clusters by controlling carbonization of polyethylene glycol （PEG）. This approach does not involve solvents yet uses the precursor itself as suspend- ing medium, thus features mild and green chemistry, and also enables the formation of uniform-sized carbon clus- ters, of which the diameter can be easily tuned from 0.7 to 3.5 nm via control of reaction time. In term of the di- mension, the resultants are denoted as sub-nano carbon clusters （SNCs） and carbon dots （CDs）, respectively. Bene- fiting from surface anchored PEG segments, both of the two show favorable flowability at room temperature and excellent solubility in aqueous and organic solvents. Comparison of their optical performances and structures re- veals that they share the same chromophores. Particularly, the SNCs demonstrate robust photo- and pH-stable pho- toluminescence and can be directly applied to cell-imaging regarding to its prominent biocompatibility. Moreover, its quantum yield （5.5%）, which is approximately 3 times higher than that of CDs （1.5%）, can be dramatically en- hanced to 18.8% by facile chemical reduction. We anticipate that these PEG derivatives marked with easy synthesis, controllable optical performances and excellent physical properties will be highly appealing in future applications.