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1.
With consumer electronics transitioning toward flexible products, there is a growing need for high-performance, mechanically robust, and inexpensive transparent conductors (TCs) for optoelectronic device integration. Herein, we report the scalable fabrication of highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films via solution shearing. Specific control over deposition conditions allows for tunable phase separation and preferential PEDOT backbone alignment, resulting in record-high electrical conductivities of 4,600 ± 100 S/cm while maintaining high optical transparency. High-performance solution-sheared TC PEDOT:PSS films were used as patterned electrodes in capacitive touch sensors and organic photovoltaics to demonstrate practical viability in optoelectronic applications.Conductive films of high optical transparency are required in a myriad of applications, including electromagnetic shielding, antistatic layers, lighting displays, touch sensors, and as electrodes for photovoltaics (1, 2). As flexible, lightweight displays for televisions and portable consumer electronics become closer to reality, emerging transparent conductors (TCs) need to be mechanically robust (3). An ideal TC, therefore, should have a sheet resistance <100 Ω/□, transmissivity greater than 0.90, and be inherently flexible, all while remaining inexpensive to process on a mass scale (4).Indium tin oxide (ITO) is the most widely used TC material due to the combination of low sheet resistance and high transparency when grown on a variety of substrates. Although common to use, ITO is an expensive material due to the requirement for vacuum deposition and a number of postprocessing steps (5). For example, in organic photovoltaic (OPV) modules ITO was estimated to represent 24% of the module cost (6). However, alternative transparent conductor materials, such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are estimated to comprise only ∼1% of an OPV module cost. Additionally, ITO is not compatible with flexible applications, because small applied strains of as little as 4.5% lead to an order of magnitude increase in the resistance (7).In recent years there have been a number of emerging TC materials studied in the literature ranging from metal nanowires (Au, Ag, Cu) (811), conducting carbon allotropes (graphene, carbon nanotubes) (1215), conducting polymers (16, 17), and other hybrid approaches (18). Recent attempts using metal nanotroughs by Wu et al. have resulted in superior optoelectronic properties with a sheet resistance of 2 Ω/□ at 90% transmission (19). The use of metal mesoscale grids further enhanced the properties of metal nanowires electrodes to a sheet resistance of 0.36 Ω/□ at 92% transmission (20). Although metal nanowires combine low resistance and high transparency, they have inferior flexibility and stretchability compared with polymer-based TCs (3).PEDOT:PSS consists of insoluble PEDOT that is charge stabilized by PSS (Fig. 1A), which affords good solubility in aqueous formulations. Within these solutions, PEDOT:PSS forms micelles where hydrophilic PSS is in contact with water and hydrophobic PEDOT is located in the micelle core (21). Upon spin-coating from solution, the micelles are deposited as a film and can have conductivities on the order of ∼1 S/cm (22). Subsequent annealing, treatment with cosolvents, and postprocessing steps can increase the conductivity of films to over 3,000 S/cm (23, 24). High-performing spin-cast PEDOT:PSS TCs have reached a sheet resistance of 46 Ω/□ at 90% transmission (25, 26). Furthermore, it is compatible with flexible electronics as films can withstand over 90% applied strain without electrical breakdown (7).Open in a separate windowFig. 1.Schematic of solution shearing process. (A) Chemical structure of PEDOT:PSS. (B) Schematic of the solution shearing design and (C) patterning PEDOT:PSS via selective patterning of solvent wetting and dewetting regions.There is a wide variety of solution processing techniques used to deposit uniform, low-roughness films (27). Spin-casting is a popular laboratory-scale deposition technique due to its simplicity and ability to deposit high-quality films with a variety of materials. However, it is a batch process that is difficult to implement on a continuous mass production scale. Furthermore, it is difficult to use elevated substrate temperatures during spin-coating, a parameter that may play a role in the final film characteristics. Contrarily, scalable fabrication through solution shearing allows for tunable deposition conditions which enable enhanced kinetic control resulting in large impacts on the electrical performance of organic electronics (2830).In this work we use solution shearing to fabricate high-performance TC PEDOT:PSS films (Fig. 1B). Tunable control of PEDOT backbone orientation, local ordering, and phase separation is demonstrated via precise control of the deposition parameters. Record-high PEDOT:PSS conductivities of 4,600 ± 100 S/cm are obtained and reach a sheet resistance of 17 ± 1 Ω/□ at 97.2 ± 0.4% transmission. A patterning method (Fig. 1C) is also developed which enables the use of high-conductivity transparent conductive films in capacitive pressure sensors and OPV devices.  相似文献   
2.
The design of a novel band-pass filter with narrow-band features based on an electromagnetic resonator at 6.4 GHz is presented. A prototype is manufactured and characterized in terms of transmission and reflection coefficient. The selective passband and suppression of the second harmonic make the filter suitable to be used in a C band frequency range for radar systems and satellite/terrestrial applications. To avoid substantial interference for this kind of applications, passive components with narrow band features and small dimensions are required. Between 3.6 GHz and 4.2 GHz the band-pass filter with harmonic suppression should have an attenuation of at least 35 dB, whereas for a passband, less than 10% is sufficient.  相似文献   
3.
Xinning Ho  Jun Wei 《Materials》2013,6(6):2155-2181
The demand for transparent conductors is expected to grow rapidly as electronic devices, such as touch screens, displays, solid state lighting and photovoltaics become ubiquitous in our lives. Doped metal oxides, especially indium tin oxide, are the commonly used materials for transparent conductors. As there are some drawbacks to this class of materials, exploration of alternative materials has been conducted. There is an interest in films of carbon nanomaterials such as, carbon nanotubes and graphene as they exhibit outstanding properties. This article reviews the synthesis and assembly of these films and their post-treatment. These processes determine the film performance and understanding of this platform will be useful for future work to improve the film performance.  相似文献   
4.
5.
现代城市电力电缆普遍密布于城网中,电缆的导体连接管相当于道路桥梁的功能,任何接头的连接管失效造成电能“断流”,即会出现大面积停电。从电缆运行管理和安全供电观点上权衡,必须重视导体连接。 本文对电缆导体连接与国家标准GB/T14315-2008版压接型连接管的结构尺寸存在差异等问题进行分析,并建议标准起草、发布部门重新编制与国际IEC标准接轨的电缆导体系列规格尺寸。  相似文献   
6.
我国电缆导体及导体压接型连接金具产品标准相对滞后于电力电缆产品及连接金具产品的发展,高于35kV的电缆导体连接金具尚无参考试验标准。不利于保证电力电缆安全稳定运行、不利于电缆线路的动态增容等工作的开展。  相似文献   
7.
近年来随着心脏疾病越来越为人们所重视,用心脏仿真模型研究各种心脏疾病的应用新研究成为热点;与此同时,在仿真理论方面也向着更加真实地反映复杂的人体环境和更加简单易操作两方面发展,研究者们发表了很多新的研究成果。从源、容积导体及算法等方面综述了心脏仿真建模理论的最新发展。  相似文献   
8.
β-AgI的电导率σ随ZrO_2含量的增加而增强。当ZrO_2以50%摩尔比掺入到AgI中时,室温电导率增加两个数量级以上,相应的激活能由纯AgI的0.54eV下降到0.35eV,电池的放电性能有明显的改善。根据离子晶体的空间电荷层理论,使用高电导层的连续沟通模型,可较好地解释σ的增强机理。  相似文献   
9.
对两种性能较好的快离子导体Na_3Zr_2Si_2P_3O_(12)(Nasicon)和Li_(1.8)Ti_(1.2)·Cr_(0.8)P_3O_(12)用喷雾干燥法和冰冻干燥法制备粉料和陶瓷烧结,并对样品进行了X射线衍射分析,形貌和显微结构观察以及阻抗谱测量等。实验结果表明:两种方法制备的粉料具有颗粒细,均匀性好,合成温度低等优点。在300℃时,两种样品的电阻半分别为10.05 Ω.cm和94.8 Ω.cm。激活能分别为0.25 eV和0.27ev。  相似文献   
10.
The performances of three widely different cathode materials (Pt, strontium-doped lanthanum manganite (LSM), and NiO) have been compared for use with proton conducting Li2SO4–Al2O3 composite electrolyte, using H2S–air and H2–air fuel cells operating at 600 °C. Surface analysis and electrochemical techniques were used to characterize fresh and used electrode materials. Pt or LSM cathodes each became covered with Li2SO4 and Al2O3 and, as a consequence, the fuel cells showed poor performance. In contrast, the NiO cathode catalyst did not become covered with Li2SO4 and good fuel cell performance was achieved. Exceptionally good current densities of over 100 mA/cm2 and power densities of over 30 mW/cm2 were obtained for H2S–air fuel cells having Mo–Ni–S anode catalysts. Slight agglomeration of NiO particles during fuel cell operation had only a minor effect on performance.  相似文献   
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