纳米银导电油墨及其在柔性印刷电子中的应用

目的 探究纳米银导电油墨及其在柔性印刷电子中的应用。方法 通过总结国内外文献,从纳米银颗粒及其导电油墨的制备、印刷工艺、烧结工艺以及在柔性印刷电子技术中的应用几方面总结近年来的研究进展。结果 在油墨制备及使用中,简化制备工艺、降低生产成本、实现绿色环保、低温烧结,同时提高油墨的基材适应性是未来纳米银导电油墨的改进重点。直写技术具有精度高、速度快等优势,正逐渐替代丝网印刷技术成为主流。烧结工艺的研究重点在于实现低温烧结,其中化学烧结工艺简单,但提高导电性是研究重点。其他烧结方式则设备昂贵,环境要求高。结论 作为功能性电子材料,纳米银导电油墨因出色的电性能和印刷适性,正在被广泛应用于柔性印刷电子中。近年来通过对纳米银及其导电油墨的深入研究及技术改进,在纳米银颗粒的制备、低温烧结技术、节能环保加工工艺等方面获得了一定的进展。与此同时,将其作为功能材料应用于制备柔性传感器中,RFID标签天线、柔性电极、超级电容器、太阳能电池等正受到广泛研究与应用。     

导电油墨及其印刷技术的研究进展

目的 综述导电油墨及其印刷方式的研究进展,为开发价格低廉、性能稳定、导电性优良的导电油墨提供参考。方法 通过查阅文献归纳各类导电油墨的制备方式、印刷方式和应用领域,对导电油墨进行系统分类,比较各类导电油墨的性能和优缺点,并对其印刷技术进行分析,展望了导电油墨的发展前景。结果 目前关于导电油墨的研究集中在纳米银、纳米铜、石墨烯等导电填料的低温烧结油墨,主要采用丝网印刷、喷墨印刷等印刷方式,多用于制备传感器、柔性可穿戴设备等。未来的研究仍需关注如何低成本、低能耗、简单大量地制造导电油墨。结论 导电油墨的制备将与环境友好型的印刷方式相结合,向高导电性、高印刷适性发展,成为印刷电子领域的关键技术。     

还原氧化石墨烯基纳米银线透明导电薄膜研究进展

透明导电薄膜已广泛应用于印刷电子领域,传统的透明导电薄膜氧化铟锡（ITO）因其高脆性低柔韧性而不能满足高速发展的柔性电子行业;纳米银线（AgNWs）和石墨烯均具有良好光学性能、导电性能以及机械性能,使其能成为制备透明导电薄膜的理想材料。综述了近年来还原氧化石墨烯（rGO）基AgNWs透明导电薄膜的研究进展。介绍了柔性导电薄膜的关键参数及rGO/AgNWs透明导电薄膜的成膜工艺;归纳了影响rGO/AgNWs透明导电薄膜光电性能的主要因素和相关研究;阐述了rGO/AgNWs透明导电薄膜在印刷电子领域的应用现状,并展望了rGO/AgNWs透明导电薄膜的未来发展趋势。     

生态导电油墨及其在包装领域的应用研究进展

导电油墨的制备已成为加快印刷电子发展的重要技术之一,近年来符合生态理念的导电油墨逐渐成为研究热点。通过对生态导电油墨的相关文献进行分析与梳理,综述了生态导电油墨的研究现状、导电机理和应用方向。归纳出生态导电油墨主要可分为溶剂型和能量固化型两类,总结了生态导电油墨在智能包装中的应用,如：印刷柔性电池、电子交互包装、RFID标签、薄膜开关等,此类产品为包装在智能交互、信息追踪溯源、防伪防盗等方面提供强力的技术支持。     

低电阻高柔性石墨导电浆料的制备和性能

针对柔性电子元器件中印刷导电线路耐弯曲折叠性差的问题,通过浆料有机载体用双酚A环氧树脂碳链中引入高柔性硅氧键,增加分子链柔性;以及采用甲醚化氨基树脂作为潜伏性固化剂,降低热固化温度和热固化膜中交联点数量,提高印刷固化膜柔性;优选具有高导电性能、粒度分布主要在5~10微米片状石墨粉为导电功能相;采用多次高速分散-真空排泡分散技术;制备了高石墨填充密度(低电阻)、高均匀性的石墨导电油墨。研究测试了油墨的丝网印刷适性、固化膜的导电性和柔性。结果表明:石墨导电浆料具有很好的丝网印刷适性,固化膜电阻低、柔性好。     

草酸处理制备抗氧化的纳米铜导电油墨

目的 研究制备抗氧化纳米铜的化学方法, 以提高纳米铜油墨的导电性。方法 液相还原法制备纳米铜, 在乙醇中用草酸处理后, 混合丙烯酸树脂配成导电油墨, 丝网印刷于PI膜上。对纳米铜和铜膜进行XRD, TEM, SEM, XPS表征。结果 经草酸处理后, 铜膜导电性得到显著提高, 250 ℃真空烧结1 h, 电阻率低至24.1 μΩ·cm。结论 经草酸处理的纳米铜油墨具有抗氧化性, 导电性满足印刷电子要求。     

低温沉积SiO2薄膜工艺的研究

利用等离子体增强化学气相沉积系统（PECVD）研究SiO2薄膜低温制备工艺,分析工艺条件对薄膜性能参数影响,通过调节射频功率优化薄膜应力,在150℃低温下获得接近零应力SiO2薄膜,薄膜沉积速率约为40nm／min,片内均匀性优于3％,折射率为1．46±0．003,并具有良好的附着力和抗蚀性能。由于沉积温度低,薄膜性能好,因此可以作为绝缘层或介质层,应用于柔性电子领域。     

镓基液态金属导电油墨及其图形化应用

目的 提出发展液态金属导电油墨的基本途径及其对信息产业发展重要性。方法 从导电油墨的制备方法、液态金属粒子的物理特性、液态金属油墨图形化及其应用展开论述,全面总结液态金属导电油墨的技术现状以及深化对其的认识。结果 液态金属基导电油墨将比目前贵金银基导电油墨的成本低50倍,基于液态金属的导电油墨图形化印刷电子在智能防伪包装、柔性电子、生物医用等领域呈快速发展趋势。结论 镓基液态金属导电油墨及其印刷技术是一个崭新的技术革命,具有重要的研究价值和经济意义。     

电弧放电法制备石墨烯及其在导电油墨中的应用

导电油墨是印刷电子技术中使用的关键电子材料, 而导电填料作为导电油墨的主要成分要求其化学性能稳定且电导率高。其中, 基于石墨烯的导电油墨因为其、透射电子显微镜、拉曼光谱等手段对制备的石墨烯进行了表征。结果表明: 直流电弧放电法制备的石墨烯为2~10层、尺寸在100~200 nm范围且纯度高、结晶性好。在此基础上, 研究了涂层厚度、热处理温度以及弯曲角度等对石墨烯导电油墨导电性能的影响。研究发现, 石墨烯导电油墨电阻率与涂层厚度、热处理温度成反比, 且随着厚度、温度的增加石墨烯导电油墨的电阻率逐渐降低。并且样品在柔性基底上经过不同角度的弯曲折叠后电阻率没有明显变化。当厚度为170 μm的样品经过360℃ (30 min) 热处理后, 石墨烯导电油墨的电阻率仅为0.003 Ω·cm。上述结果表明, 电弧法制备的石墨烯导电油墨有望成为未来印制电子领域的关键材料。     

纳米铜导电油墨的制备及其应用

综述了纳米铜粒子的制备方法,即机械球磨法、辐射合成法、物理气相沉积法等物理制备法及化学制备法,探讨了改进纳米铜导电油墨防氧化、低温烧结、导电性能等关键问题,以及纳米铜导电油墨在印刷RFID电子标签、薄膜开关、触摸屏等方面的应用,并提出纳米铜导电油墨未来的研究方向为：抗氧化、低温烧结、多种印刷方式及产品应用等研究。     

Application Challenges in Fiber and Textile Electronics

Modern electronic devices are moving toward miniaturization and integration with an emerging focus on wearable electronics. Due to their close contact with the human body, wearable electronics have new requirements including low weight, small size, and flexibility. Conventional 3D and 2D electronic devices fail to efficiently meet these requirements due to their rigidity and bulkiness. Hence, a new family of 1D fiber-shaped electronic devices including energy-harvesting devices, energy-storage devices, light-emitting devices, and sensing devices has risen to the challenge due to their small diameter, lightweight, flexibility, and weavability into soft textile electronics. The application challenges faced by fiber and textile electronics from single fiber-shaped devices to continuously scalable fabrication, to encapsulation and testing, and to application mode exploration, are discussed. The evolutionary trends of fiber and textile electronics are then summarized. Finally, future directions required to boost their commercialization are highlighted.     

Recent Advances in 1D Stretchable Electrodes and Devices for Textile and Wearable Electronics: Materials,Fabrications, and Applications

Research on wearable electronic devices that can be directly integrated into daily textiles or clothes has been explosively grown holding great potential for various practical wearable applications. These wearable electronic devices strongly demand 1D electronic devices that are light–weight, weavable, highly flexible, stretchable, and adaptable to comport to frequent deformations during usage in daily life. To this end, the development of 1D electrodes with high stretchability and electrical performance is fundamentally essential. Herein, the recent process of 1D stretchable electrodes for wearable and textile electronics is described, focusing on representative conductive materials, fabrication techniques for 1D stretchable electrodes with high performance, and designs and applications of various 1D stretchable electronic devices. To conclude, discussions are presented regarding limitations and perspectives of current materials and devices in terms of performance and scientific understanding that should be considered for further advances.     

Soft Elastomers with Ionic Liquid‐Filled Cavities as Strain Isolating Substrates for Wearable Electronics

Managing the mechanical mismatch between hard semiconductor components and soft biological tissues represents a key challenge in the development of advanced forms of wearable electronic devices. An ultralow modulus material or a liquid that surrounds the electronics and resides in a thin elastomeric shell provides a strain‐isolation effect that enhances not only the wearability but also the range of stretchability in suitably designed devices. The results presented here build on these concepts by (1) replacing traditional liquids explored in the past, which have some nonnegligible vapor pressure and finite permeability through the encapsulating elastomers, with ionic liquids to eliminate any possibility for leakage or evaporation, and (2) positioning the liquid between the electronics and the skin, within an enclosed, elastomeric microfluidic space, but not in direct contact with the active elements of the system, to avoid any negative consequences on electronic performance. Combined experimental and theoretical results establish the strain‐isolating effects of this system, and the considerations that dictate mechanical collapse of the fluid‐filled cavity. Examples in skin‐mounted wearable include wireless sensors for measuring temperature and wired systems for recording mechano‐acoustic responses.     

Organic Photodetectors for Next-Generation Wearable Electronics

Next-generation wearable electronics will need to be mechanically flexible and stretchable such that they can be conformally attached onto the human body. Photodetectors that are available in today's market are based on rigid inorganic crystalline materials and they have limited mechanical flexibility. In contrast, photodetectors based on organic polymers and molecules have emerged as promising alternatives due to their inherent mechanical softness, ease of processing, tunable optoelectronic properties, good light sensing performance, and biocompatibility. Here, the recent advances of organic photodetectors in terms of both optoelectronic and mechanical properties are outlined and discussed, and their application in wearable electronics including health monitoring sensors, artificial vision, and self-powering integrated devices are highlighted.     

Ultraflexible and Lightweight Bamboo‐Derived Transparent Electrodes for Perovskite Solar Cells

Wearable devices are mainly based on plastic substrates, such as polyethylene terephthalate and polyethylene naphthalate, which causes environmental pollution after use due to the long decomposition periods. This work reports on the fabrication of a biodegradable and biocompatible transparent conductive electrode derived from bamboo for flexible perovskite solar cells. The conductive bioelectrode exhibits extremely flexible and light‐weight properties. After bending 3000 times at a 4 mm curvature radius or even undergoing a crumpling test, it still shows excellent electrical performance and negligible decay. The performance of the bamboo‐based bioelectrode perovskite solar cell exhibits a record power conversion efficiency (PCE) of 11.68%, showing the highest efficiency among all reported biomass‐based perovskite solar cells. It is remarkable that this flexible device has a highly bendable mechanical stability, maintaining over 70% of its original PCE during 1000 bending cycles at a 4 mm curvature radius. This work paves the way for perovskite solar cells toward comfortable and environmentally friendly wearable devices.     

Stretchable,Curvilinear Electronics Based on Inorganic Materials

All commercial forms of electronic/optoelectronic technologies use planar, rigid substrates. Device possibilities that exploit bio‐inspired designs or require intimate integration with the human body demand curvilinear shapes and/or elastic responses to large strain deformations. This article reviews progress in research designed to accomplish these outcomes with established, high‐performance inorganic electronic materials and modest modifications to conventional, planar processing techniques. We outline the most well developed strategies and illustrate their use in demonstrator devices that exploit unique combinations of shape, mechanical properties and electronic performance. We conclude with an outlook on the challenges and opportunities for this emerging area of materials science and engineering.     

EGaIn‐Assisted Room‐Temperature Sintering of Silver Nanoparticles for Stretchable,Inkjet‐Printed,Thin‐Film Electronics

Coating inkjet‐printed traces of silver nanoparticle (AgNP) ink with a thin layer of eutectic gallium indium (EGaIn) increases the electrical conductivity by six‐orders of magnitude and significantly improves tolerance to tensile strain. This enhancement is achieved through a room‐temperature “sintering” process in which the liquid‐phase EGaIn alloy binds the AgNP particles (≈100 nm diameter) to form a continuous conductive trace. Ultrathin and hydrographically transferrable electronics are produced by printing traces with a composition of AgNP‐Ga‐In on a 5 µm‐thick temporary tattoo paper. The printed circuit is flexible enough to remain functional when deformed and can support strains above 80% with modest electromechanical coupling (gauge factor ≈1). These mechanically robust thin‐film circuits are well suited for transfer to highly curved and nondevelopable 3D surfaces as well as skin and other soft deformable substrates. In contrast to other stretchable tattoo‐like electronics, the low‐cost processing steps introduced here eliminate the need for cleanroom fabrication and instead requires only a commercial desktop printer. Most significantly, it enables functionalities like “electronic tattoos” and 3D hydrographic transfer that have not been previously reported with EGaIn or EGaIn‐based biphasic electronics.