印刷电子用导电油墨的研究进展

印刷电子技术应用的关键在于导电油墨的研发,目前研究制备的导电油墨存在成本高、导电性差、热处理温度高等缺点,开发成本低、导电性良好、热处理温度低的导电油墨已成必然。介绍了导电油墨的应用领域和导电油墨的分类,概述了导电油墨的研究工作,并在此基础上综述了无颗粒型导电油墨的优势,展望了未来印刷电子用导电油墨的发展方向。     

聚噻吩基导电油墨的制备及其印刷适性研究

聚噻吩及其衍生物具有高导电性、环保性、热稳定性等优点,将其 制备成导电油墨,在印刷电子和智能包装等领域中极具应用前景。本文以聚（3, 4- 乙撑二氧噻吩）（PEDOT）、导电炭黑（CB）以及羧甲基纤维素钠（CMC） 为主体,采用原位聚合法制备了 PEDOT-CB/CMC 导电油墨。系统地研究了 连接料、辅助添加剂及烧结温度等对油墨黏度、附着力、分散性和导电性能 的影响;并借助于丝网印刷技术对油墨的印刷适性进行了研究。结果表明, 导电油墨具备良好的分散性和附着力;印品经烧结处理后,其电阻值明显下 降并随墨条长度、宽度的增加呈现规律性变化。另外,导电油墨在纸、塑料、 棉布等不同基材上均能满足丝网印刷的要求。     

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。     

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。     

纳米银导电油墨的制备研究与包装应用概论

纳米导电油墨具有独特的物理及化学性质,而导电填料则决定导电油墨的性能。概述了纳米导电油墨的组成、分类及特点,主要论述了纳米银的特性,相较于其他填料,纳米银具备良好的导电性、导热性、纳米光学性、高比表面积等特性,因而纳米银作为导电填料成为了制备导电油墨的首选;进一步阐述了纳米银的制备方法及纳米银导电油墨的配方设计及制备工艺,通过不同的研究分析了纳米银导电油墨性能的影响因素,以及纳米银导电油墨在不同包装应用的发展趋势,并对其应用研究提出了建议。     

液相剥离法制备石墨烯导电油墨的研究进展

目的 综述液相剥离法制备石墨烯导电油墨的研究现状，为促进石墨烯导电油墨在印刷电子领域的应用提供参考。方法 针对各种形式液相剥离制备石墨烯导电油墨的方法，分别从所使用溶剂的物理化学性能、制备流程、制得石墨烯导电油墨的性能等方面进行归纳和对比。结果 目前，液相剥离法制备石墨烯导电油墨的研究主要集中在提升石墨烯的分散性和油墨的导电性能等方面，未来需关注液相剥离过程中溶剂和助剂的选择，沿着低成本、绿色化、产业化等方向发展。     

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。     

复合碳系导电油墨的制备及性能研究

目的 研究碳纳米管与石墨烯对复合碳系导电油墨性能的影响,开发性能优异的导电油墨。方法 分别探究碳纳米管管径尺寸、碳纳米管与石墨烯的配比、油墨中的碳质量分数及油墨涂层厚度对复合碳系导电油墨导电性的影响,并基于实验数据对各影响因素拟合出相应的预测模型。最终确定油墨的优选配比,并对采用优选配比制备的导电油墨涂层进行电热转换测试。结果 由石墨烯和管径尺寸为25nm的多壁碳纳米管为导电填料制备的导电油墨涂层综合导电性能最优,当导电油墨中碳质量分数为2.5%（纳米管质量分数为0.125%、石墨烯质量分数为2.375%）、水性丙烯酸树脂质量分数为5.25%、油墨涂层固化后厚度为0.147 mm时,油墨导电涂层电阻率为0.089 3Ω·cm。在外接电压为5 V的条件下,导电油墨的功率为13.49 W,由室温通电工作至100℃仅需13.723 s,油墨涂层发热均匀性满足JG/T 286—2020的要求。结论 采用优选配比制备的油墨涂层内部搭建起均匀丰富的导电网络,极大地提升了油墨的导电性,使得油墨电热性能优异。     

碳纳米管对碳系导电油墨电热性能的影响

目的 研究碳纳米管对碳系水性导电油墨电热性能的影响,寻找最佳含量的发热油墨。方法 采用单因素法,在原有碳系水性导电油墨中通过添加不同含量的碳纳米管制备多组碳系水性电热油墨。通过测试其SEM、TEM、电热功率、接触角等探究碳系水性电热油墨的最佳制备配方。结果 不同碳纳米管含量的碳系水性电热油墨其发热温度、电功率具有一定的差异。在其他条件一定的情况下,随着碳纳米管含量的增加,碳系水性导电油墨的电热导电性先降低再升高。当碳纳米管质量分数为0.75%时,碳系水性导电油墨的可以达到温度最高（147℃）,功率相对较低（4.4 W）,此时为导电性最佳碳系水性电热油墨的配方。结论 在导电油墨中添加适量的碳纳米管可改善油墨的加热性能。     

分散剂含量对碳系导电油墨导电性能影响的研究

目的研究分散剂的含量对碳导电油墨导电性能和表面性能的影响。方法以德谦W-920为分散剂,采用单因素法,保持碳导电油墨其他组分不变,改变分散剂的配置比例,制备不同组碳系导电油墨。最后通过SEM图表征墨膜的形貌。结果不同含量的分散剂对导电油墨的性能产生一定差异。在其他条件一定的情况下,随着分散剂比例的增加,导电性先上升后下降。结论分散剂的加入对导电油墨的性能起着重要作用,当分散剂的质量分数达到7%时,体积电阻率为3.01×10-2Ω·m,此时可以有效改善导电油墨的导电性和墨膜的规整性。     

Printed UHF RFID antennas with high efficiencies using nano-particle silver ink

One of the most popular targets of conductive ink technology is to print RFID tag antennas. However, the printed RFID antennas, manufactured by conductive silver ink which is generally based on microsized silver particles, have lower conductivity and consequently lower radiation efficiency than those by conventional copper etching method. This work demonstrates nano-particle conductive silver ink that is capable of printing UHF RFID antennas with improved radiation efficiency. Compared with commercial micro-particle silver ink, the solid content of metal is much higher in the proposed nanoparticle silver ink, leading to better electrical properties. Two types of dipole antennas are printed with the proposed nano-particle as well as with commercial micro-particle inks. Also, the same antennas are fabricated by copper etching. With these conductive inks, a straight and a meandered dipole antennas are fabricated and their radiation efficiencies are measured with the Wheeler cap method. Experimental results show that the radiation efficiencies of the antennas based on nanoparticle silver ink are superior to those printed with the micro-particle silver ink, and are comparable to those of popular copper antennas.     

Rheological properties and screen printability of UV curable conductive ink for flexible and washable E-textiles

As a critical component for the realization of flexible electronics,multifunctional electronic textiles(etextiles)still struggle to achieve controllable printing accuracy,excellent flexibility,decent washability and simple manufacturing.The printing process of conductive ink plays an important role in manufacturing e-textiles and meanwhile is also the main source of printing defects.In this work,we report the preparation of fully flexible and washable textile-based conductive circuits with screen-printing method based on novel-developed UV-curing conductive ink that contains low temperature and fast cure features.This work systematically investigated the correlation between ink formulation,rheological properties,screen printability on fabric substrates,and the electrical properties of the e-textile made thereafter.The rheological behaviors,including the thixotropic behavior and oscillatory stress sweep of the conductive inks was found depending heavily on the polymer to diluent ratio in the formulation.Subsequently,the rheological response of the inks during screen printing showed determining influence to their printability on textile,that the proper control of ink base viscosity,recovery time and storage/loss modulus is key to ensure the uniformity of printed conductive lines and therefore the electrical conductivity of fabricated e-textiles.A formulation with 24 wt%polymer and 10.8 wt%diluent meets all these stringent requirements.The conductive lines with 1.0 mm width showed exceptionally low resistivity of 2.06×10^-5Ωcm Moreover,the conductive lines presented excellent bending tolerance,and there was no significant change in the sample electrical resistance during 10 cycles of washing and drying processes.It is believed that these novel findings and the promising results of the prepared product will provide the basic guideline to the ink formulation design and applications for screen-printing electronics textiles.     

Turning Trash into Treasure: Additive Free MXene Sediment Inks for Screen-Printed Micro-Supercapacitors

Printed functional conductive inks have triggered scalable production of smart electronics such as energy-storage devices, antennas, wearable electronics, etc. Of particular interest are highly conductive-additive-free inks devoid of costly postdeposition treatments to eliminate sacrificial components. Due to the high filler concentration required, formulation of such waste-free inks has proven quite challenging. Here, additive-free, 2D titanium carbide MXene aqueous inks with appropriate rheological properties for scalable screen printing are demonstrated. Importantly, the inks consist essentially of the sediments of unetched precursor and multilayered MXene, which are usually discarded after delamination. Screen-printed structures are presented on paper with high resolution and spatial uniformity, including micro-supercapacitors, conductive tracks, integrated circuit paths, and others. It is revealed that the delaminated nanosheets among the layered particles function as efficient conductive binders, maintaining the mechanical integrity and thus the metallic conductive network. The areal capacitance (158 mF cm⁻²) and energy density (1.64 µWh cm⁻²) of the printed micro-supercapacitors are much superior to other devices based on MXene or graphene. The ink formulation strategy of “turning trash into treasure” for screen printing highlights the potential of waste-free MXene sediment printing for scalable and sustainable production of next-generation wearable smart electronics.     

Printed antennas with variable conductive ink layer thickness

One of the complex tasks in mass production of RF electronics is printing the communication antenna using electrically conductive ink. For example, this is very common for radio- frequency identification (RFID) tags. Electrical properties of the ink are mostly determined by conductive (e.g. silver) particles mixed into the ink solution and the way they `connect' in the cured ink. It is also desirable to minimise the amount of ink used per antenna, because high-conducting metals like silver used in the ink are rather expensive. Metal-based inks have limited conductivity, so the thicker the cured ink layer will be the better the antenna radiation efficiency can be achieved, but also the higher will be the costs. In the paper, the authors report on the investigations of the possibility of minimising the amount of ink used per antenna. This can be achieved by printing thicker ink layers, where antenna structures are known to have high current density. Two common antenna structures and a dedicated antenna for passive RFID are used in the investigation. The main result of the paper is that radiation efficiency depends primarily on the total amount of ink used for printing the antenna, rather than on the variations of the layer thickness within the antenna structure     

Reversible Conductive Inkjet Printing of Healable and Recyclable Electrodes on Cardboard and Paper

Conductive inkjet printing with metal nanoparticles is irreversible because the particles are sintered into a continuous metal film. The resulting structures are difficult to remove or repair and prone to cracking. Here, a hybrid ink is used to obviate the sintering step and print interconnected particle networks that become highly conductive immediately after drying. It is shown that reversible conductive printing is possible on low‐cost cardboard samples after applying standard paper industry coats that are adapted in terms of surface energy and porosity. The conductivity of the printed films approaches that of sintered standard inks on the same substrate, but the mobility of the hybrid particle film makes them less sensitive to cracks during bending and folding of the substrate. Damages that occur can be partially repaired by wetting the film such that particle mobility is increased and particles move to bridge insulating gaps in the film. It is demonstrated that the conductive material can be recovered from the cardboard at the end of its life time and be redispersed to recycle the particles and reuse them in conductive inks.     

Recent Development of Printed Micro-Supercapacitors: Printable Materials,Printing Technologies,and Perspectives

The rapid progression of portable and wearable electronics has necessitated the development of high-performing, miniaturized energy-storage devices with flexible form factors and high energy and power delivery. Printed micro-supercapacitors (MSCs), with in-plane interdigital configurations, is touted as a promising choice to fulfill these requirements. New printing technologies can assemble MSCs with fiscal and environmental benefits, large form factors, and at high throughputs, qualities not afforded with conventional microfabrication technologies. Here, recent progress in the preparation of functional ink systems for wearable MSCs, encompassing electrode materials, conductor materials, and electrolytes, is presented. First, a comprehensive background of the fundamentals of printing technology is introduced, with discussions focusing on methods of improving ink functionality while simultaneously retaining good printability. Second, various printing techniques to ensure manufacturable scaling of wearable MSCs with high areal electrochemical performance and small footprint are explored. Within the scope of these two topics, various issues that hinder the full materialization of widespread adoption of printed MSC and next steps to overcome these issues are discussed. Further deep dives in scientific and technical challenges are also presented, including limited functionality of the inks, low printing resolution, overlay accuracy, and complex encapsulation.