有机金属螯合物电致发光材料的研究

有机电致发光平板显示被誉为“２１世纪平板显示技术”,是当今平板显示研究的重点和热点。有机金属螯合物因其优良的电致发光性能,被首选为有机电致发光平板显示器的发光材料。针对近１０年来有机金属螯合物电致发光材料及其器件的研究状况,对其分子种类、分子结构与发光性能的关系、分子设计准则、电致发光机制及其最新研究进展,进行了综述,展望了其发展趋势。     

有机电致发光材料的新进展

介绍了有机电致发光材料的最新进展,对有机电致发光材料进行分类和评述,重点介绍载流子传输材料和发光材料(小分子发光材料,金属配合物发光材料和聚合物发光材料)的国内外研究现状,并对有机电致发光材料的应用前景进行评述.     

8-羟基喹啉金属配合物电致发光材料

有机/高分子电致发光器件是当前国内外平板显示器技术领域的研究热点,8-羟基喹啉金属配合物(8HQM)以其优良的电致发光性能成为研制高效率的有机/高分子电致发光器件的首选材料.针对近十年来8HQM电致发光材料的研究状况,对其电致发光机制、分子结构及发光性能的关系、分子种类及其最新研究进展,进行综述,展望了其发展趋势.     

新型有机发光材料——终二唑衍生物

本文介绍了国际上新发明的有机光致、电致发光材料—二唑衍生物的发光特性和合成路线及各步产物的表征手段。在分析了材料的分子结构特征和发光性能间关系后，探讨了用以改变材料性能的化学修饰途径。     

异佛尔酮类有机电致发光材料的研究进展

异佛尔酮只有一个可以发生缩合反应的甲基,产物合成简单,容易提纯,具有高的荧光量子效率和稳定性。综述了异佛尔酮衍生物在红色有机电致发光材料中的研究进展,对部分结构、发光性能等进行了归纳、总结,对其发展前景进行了展望。     

高效发光的吡啶嗡盐基单组份白光发射材料的研究

发展合成上简单、高发光效率的单组份有机白光发射材料具有重要的科学意义,但极具挑战性。以4′-(4-吡啶基)-2,2′:6′,2″-三联吡啶为原料,设计合成了一个简单且高发光效率的吡啶嗡盐基单组份白光发射材料。基于荧光性能研究发现,该材料在365 nm波长激发下呈现的白光量子产率高达22.4%,且该单组份白光发射材料呈现激发波长依赖的发光特性,发光颜色可从白光变为黄光。研究揭示了对阴离子对有机离子化合物的发光性能具有重要影响,调控对离子是改善有机离子化合物光学性能的一个有效策略。鉴于吡啶嗡盐基单组份白光发射材料优异的发光性能,该简单发光材料将可能应用于白光发射器件或作为信息防伪材料。     

白色有机发光材料与器件

综述了白色有机电致发光材料和器件的研究进展;归纳了获取白色有机电致发光的途径和方法;分析了多种器件结构的特点及其材料;结合研究过程中存在的某些问题,从器件的发光效率和色纯度角度,讨论了影响发光器件性能的诸因素及其改进措施.     

有机电致发光的研究进展及展望

对有机电致发光(OLEDs)的研究进展进行了综述。内容包括:有机电致发光器件的阴、阳极材料、电极修饰、发光材料、发光效率、新的器件结构以及驱动电路的研究现状。剖析了该领域的研究热点,并展望了其发展应用前景。     

有机电致发光材料的研发现状

有机电致发光器件 (OLED)具有驱动电压低、主动发光等优势 ,在平板显示领域具有极大的应用前景而引起了广泛的关注。与此同时有机电致发光材料的研发也取得了很大的进展。本文介绍了近年来有机电致发光材料 (包括小分子发光材料和聚合物发光材料 )的研发状况     

氟代有机光电功能小分子材料的研究

有机电致发光材料是有机电致发光器件的基本与核心,发展新型有机光电材料也是国际上此领域的热点。在过去的几十年里,氟化通过降低能级被用来增强小分子或者聚合物的稳定性、电子传输和双极传输性能,尤其是在有机发光二极管中,特别是C-H…F相互作用（类似氢键）在固态堆积时具有重要的作用,能引起典型的π-堆积排列方式,从而增强电荷迁移率。作者研究团队系统地研究了不同位置和数目取代的氟或三氟甲基等吸电子基团对不同材料体系吸收与发射光谱、HOMO／LUMO能级、热性质以及材料的空穴传输和发光性能的影响,同时运用量化计算进行了相应的理论分析,最终发展了一系列新型空穴传输材料、双极性的主体材料以及深蓝光的荧光客体材料。     

Solution Adsorption Formation of a π‐Conjugated Polymer/Graphene Composite for High‐Performance Field‐Effect Transistors

Semiconducting polymers with π‐conjugated electronic structures have potential application in the large‐scale printable fabrication of high‐performance electronic and optoelectronic devices. However, owing to their poor environmental stability and high‐cost synthesis, polymer semiconductors possess limited device implementation. Here, an approach for constructing a π‐conjugated polymer/graphene composite material to circumvent these limitations is provided, and then this material is patterned into 1D arrays. Driven by the π–π interaction, several‐layer polymers can be adsorbed onto the graphene planes. The low consumption of the high‐cost semiconductor polymers and the mass production of graphene contribute to the low‐cost fabrication of the π‐conjugated polymer/graphene composite materials. Based on the π‐conjugated system, a reduced π–π stacking distance between graphene and the polymer can be achieved, yielding enhanced charge‐transport properties. Owing to the incorporation of graphene, the composite material shows improved thermal stability. More generally, it is believed that the construction of the π‐conjugated composite shows clear possibility of integrating organic molecules and 2D materials into microstructure arrays for property‐by‐design fabrication of functional devices with large area, low cost, and high efficiency.     

Dithieno[3,2-f:2′,3′-h]quinoxaline-Based Photovoltaic–Thermoelectric Dual-Functional Energy-Harvesting Wide-Bandgap Polymer and its Backbone Isomer

Both organic solar cells (OSCs) and organic thermoelectrics (OTEs) are promising energy-harvesting technologies for future renewable and sustainable energy sources. Among various material systems, organic conjugated polymers are an emerging material class for the active layers of both OSCs and OTEs. However, organic conjugated polymers showing both OSC and OTE properties are rarely reported because of the different requirements toward the OSCs and OTEs. In this study, the first simultaneous investigation of the OSC and OTE properties of a wide-bandgap polymer PBQx-TF and its backbone isomer iso-PBQx-TF are reported. All wide-bandgap polymers form face-on orientations in a thin-film state, but PBQx-TF has more of a crystalline character than iso-PBQx-TF, originating from the backbone isomeric structures of α,α ′/β,β ′-connection between two thiophene rings. Additionally, iso-PBQx-TF shows inactive OSC and poor OTE properties, probably because of the absorption mismatch and unfavorable molecular orientations. At the same time, PBQx-TF exhibits both decent OSC and OTE performances, indicating that it satisfies the requirements for both OSCs and OTEs. This study presents the OSC and OTE dual-functional energy-harvesting wide-bandgap polymer and the future research directions for hybrid energy-harvesting materials.     

Conjugated Polymers for Flexible Energy Harvesting and Storage

Since the discovery of conjugated polymers in the 1970s, they have attracted considerable interest in light of their advantages of having a tunable bandgap, high electroactivity, high flexibility, and good processability compared to inorganic conducting materials. The above combined advantages make them promising for effective energy harvesting and storage, which have been widely studied in recent decades. Herein, the key advancements in the use of conjugated polymers for flexible energy harvesting and storage are reviewed. The synthesis, structure, and properties of conjugated polymers are first summarized. Then, their applications in flexible polymer solar cells, thermoelectric generators, supercapacitors, and lithium‐ion batteries are described. The remaining challenges are then discussed to highlight the future direction in the development of conjugated polymers.     

Recent Advances in Conjugated Polymers for Visible-Light-Driven Water Splitting

With the ambition of solving the challenges of the shortage of fossil fuels and their associated environmental pollution, visible-light-driven splitting of water into hydrogen and oxygen using semiconductor photocatalysts has emerged as a promising technology to provide environmentally friendly energy vectors. Among the current library of developed photocatalysts, organic conjugated polymers present unique advantages of sufficient light-absorption efficiency, excellent stability, tunable electronic properties, and economic applicability. As a class of rising photocatalysts, organic conjugated polymers offer high flexibility in tuning the framework of the backbone and porosity to fulfill the requirements for photocatalytic applications. In the past decade, significant progress has been made in visible-light-driven water splitting employing organic conjugated polymers. The recent development of the structural design principles of organic conjugated polymers (including linear, crosslinked, and supramolecular self-assembled polymers) toward efficient photocatalytic hydrogen evolution, oxygen evolution, and overall water splitting is described, thus providing a comprehensive reference for the field. Finally, current challenges and perspectives are also discussed.     

Carbon‐Rich Nanomaterials: Fascinating Hydrogen and Oxygen Electrocatalysts

Hydrogen energy is commonly considered as a clean and sustainable alternative to the traditional fossil fuels. Toward universal utilization of hydrogen energy, developing high‐efficiency, low‐cost, and sustainable energy conversion technologies, especially water‐splitting electrolyzers and fuel cells, is of paramount significance. In order to enhance the energy conversion efficiency of the water‐splitting electrolyzers and fuel cells, earth‐abundant and stable electrocatalysts are essential for accelerating the sluggish kinetics of hydrogen and oxygen reactions. In the past decade, carbon‐rich nanomaterials have emerged as a promising class of hydrogen and oxygen electrocatalysts. Here, the development and electrocatalytic activity of various carbon‐rich materials, including metal‐free carbon, conjugated porous polymers, graphdiyne, covalent organic frameworks (COFs), atomic‐metal‐doped carbon, as well as metal–organic frameworks (MOFs), are demonstrated. In particular, the correlations between their porous nanostructures/electronic structures of active centers and electrocatalytic performances are emphatically discussed. Therefore, this review article guides the rational design and synthesis of high‐performance, metal‐free, and noble‐metal‐free carbon‐rich electrocatalysts and eventually advances the rapid development of water‐splitting electrolyzers and fuel cells toward practical applications.     

Patterning of conjugated polymers for organic optoelectronic devices

Conjugated polymers have been attracting more and more attention because they possess various novel electrical, magnetical, and optical properties, which render them useful in modern organic optoelectronic devices. Due to their organic nature, conjugated polymers are light-weight and can be fabricated into flexible appliances. Significant research efforts have been devoted to developing new organic materials to make them competitive with their conventional inorganic counterparts. It is foreseeable that when large-scale industrial manufacture of the devices made from organic conjugated polymers is feasible, they would be much cheaper and have more functions. On one hand, in order to improve the performance of organic optoelectronic devices, it is essential to tune their surface morphologies by techniques such as patterning. On the other hand, patterning is the routine requirement for device processing. In this review, the recent progress in the patterning of conjugated polymers for high-performance optoelectronic devices is summarized. Patterning based on the bottom-up and top-down methods are introduced. Emerging new patterning strategies and future trends for conventional patterning techniques are discussed.     

Side Chain Redistribution as a Strategy to Boost Organic Electrochemical Transistor Performance and Stability

A series of glycolated polythiophenes for use in organic electrochemical transistors (OECTs) is designed and synthesized, differing in the distribution of their ethylene glycol chains that are tethered to the conjugated backbone. While side chain redistribution does not have a significant impact on the optoelectronic properties of the polymers, this molecular engineering strategy strongly impacts the water uptake achieved in the polymers. By careful optimization of the water uptake in the polymer films, OECTs with unprecedented steady-state performances in terms of [μC^*] and current retentions up to 98% over 700 electrochemical switching cycles are developed.     

Synthesis and characterization of fluorescent poly(oxadiazole)s containing 3,4-dialkoxythiophenes

We report the synthesis, optical and electrochemical details, and properties of three conjugated copolymers (P1–P3) consisting of alternate hole-transporting thiophene derivative and electron-transporting 1,3,4-oxadiazole units. The polymers are prepared using the precursor polyhydrazide route. The polymers have well defined structure and exhibit good thermal stability with the onset decomposition temperature in nitrogen at around 300 °C. All the polymers are soluble in organic solvents such as DMF, DMSO, NMP and in strong organic acids like trifluoroacetic acid. The optical and charge-transporting properties of the polymers are investigated by UV–visible spectroscopy, fluorescence emission spectroscopy and cyclic voltammetry. The UV–visible absorption spectra of polymers in solution showed a maximum at around 400 nm. The polymers depicted green fluorescence both in solution and as thin films. Cyclic voltammetry studies reveal that these copolymers have low-lying LUMO energy levels ranging from −3.28 to −3.36 eV and high-lying HOMO energy levels ranging from −5.5 to −5.56 eV, which indicated that they may be promising candidates for electron-transporting or hole-blocking materials in light-emitting diodes.     

Conjugated Polymer Shells on Colloidal Templates by Seeded Suzuki–Miyaura Dispersion Polymerization

The self‐assembly of colloidal conjugated polymers presents a versatile and powerful oute towards new functional optoelectronic materials and devices. However, this strategy relies on the existence of chemical protocols to prepare highly monodisperse colloids of conjugated polymers in high yields. Here, a recently developed Suzuki–Miyaura dispersion polymerization method is adopted to synthesize core–shell particles, in which a conjugated polymer shell is grown onto non‐conjugated organic and inorganic colloidal templates. By chemically anchoring aryl halide groups at the particle surface, a conjugated polymer shell can be attached to a wide variety of organic and inorganic microparticles. In this way, both spherical and non‐spherical hybrid conjugated polymer particles are prepared, and it is shown that the method can be applied to a variety of conjugated polymers. This new method offers independent control of the size, shape and photophysical properties of these novel conjugated polymer particles.     

Enhanced Charge Injection Properties of Organic Field‐Effect Transistor by Molecular Implantation Doping

Organic semiconductors (OSCs) have been widely studied due to their merits such as mechanical flexibility, solution processability, and large‐area fabrication. However, OSC devices still have to overcome contact resistance issues for better performances. Because of the Schottky contact at the metal–OSC interfaces, a non‐ideal transfer curve feature often appears in the low‐drain voltage region. To improve the contact properties of OSCs, there have been several methods reported, including interface treatment by self‐assembled monolayers and introducing charge injection layers. Here, a selective contact doping of 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F₄‐TCNQ) by solid‐state diffusion in poly(2,5‐bis(3‐hexadecylthiophen‐2‐yl)thieno[3,2‐b]thiophene) (PBTTT) to enhance carrier injection in bottom‐gate PBTTT organic field‐effect transistors (OFETs) is demonstrated. Furthermore, the effect of post‐doping treatment on diffusion of F₄‐TCNQ molecules in order to improve the device stability is investigated. In addition, the application of the doping technique to the low‐voltage operation of PBTTT OFETs with high‐k gate dielectrics demonstrated a potential for designing scalable and low‐power organic devices by utilizing doping of conjugated polymers.