Inkjet printing is one of the key technologies behind the direct writing revolution, spanning an ever-increasing number of applications. During recent years, print-head technology has turned academic research into a viable manufacturing solution. Modern inkjet technology allows accurate printing to form functional components through additive deposition of a variety of materials, including ceramics, conductive polymers and now, metal oxides. Transparent Conducting OxidesPatterning Technologies Ltd (PTL), a company at the forefront of several direct writing technologies, is using its know-how to enable the direct patterning of transparent conducting oxide (TCO) films and circuits. These metal oxides are already used for making a broad range of advanced products, including flat panel displays, energy conserving architectural windows, and de-fogging windows for cars and aircraft. Patterned transparent conducting oxides are increasingly being used in displays for making the interconnections between the electronics and the pixel pad. 在薄膜中透明导电氧化ISTOR（TFT）平板显示器透明导电氧化物互连可与任何薄膜晶体管（TFT）一起使用，包括由塑料逻辑开发的塑料电子产品的类型。在液晶显示器中，晶体管通过在透明导电氧化物像素垫周围创建电场来关闭液晶并关闭液晶。显示诸如此类的应用程序通常需要125欧姆/平方英尺的透明传导氧化物电阻。 Advantages of Using Inkjet Technology over More Conventional Techniques在当前的加工方法中，用氧化锡（ITO）掺杂的氧化酰化氧化物使用溅射涂层技术沉积，因此覆盖了底物的整个面积。虽然这适用于某些应用，但其他则需要垫子和电气互连的图案。创建图案层是一个耗时，昂贵的多阶段过程，涉及光刻掩盖并蚀刻不需要的材料。相比之下，PTL开发的新方法可在更少的时间内提供更便宜的图案透明导电氧化物层。通过使用喷墨技术，不仅处理更便宜，而且材料本身便宜，需要较低的掺杂元素浓度。欧洲杯足球竞彩 Indium Tin Oxide Circuit Deposition and Properties到目前为止，溅射一直是产生透明导电氧化膜和电路的主要技术，尽管ITO已被极大地用于生产电路，部分原因是它被蚀刻了。这些薄膜传导的机制需要大量的可用电荷载体，以游离电子和氧晶格空位的形式。但是，这种高密度的电荷载体也导致光吸收增加，从而降低了光学传输。尽管一张材料的电阻可以低至10欧姆/平方英尺，但可见的传输最多只能为80％。对于大于90％的传输速率，电阻通常为100欧姆/平方英尺或更高。ITO膜的这些和其他特性取决于所使用的溅射目标的沉积参数和启动组成。 用于透明导电氧化物的喷墨打印过程但是，在PTL过程中，其他因素也起作用。当制造纳米透明透明导电材料的喷墨沉积时，膜的颗粒堆积和干燥对于材料的性能至关重要。欧洲杯足球竞彩该过程需要包括一些“冷冻”表面上合并的液滴的方法，以便保留图案结构和颗粒堆积。PTL使用专利的工艺，该工艺使用电磁辐射控制底物表面上的流体。 实际上，印刷技术集成了印刷头，墨水，图像“冷冻”的方法以及实现最佳沉积的基板。该过程考虑了墨水弹出力学，墨水在底物上的粘弹性行为以及底物预处理。除了这些沉积特性外，流体还必须赋予所需的功能性能。虽然墨水是为了实现这些特征而制定的，但干燥过程对膜的性能产生了最大的影响。例如，干燥速率会影响颗粒堆积密度和通过材料的电路路径 - 膜中的密度越大，其产生的导体越好。 技术的起源
PTL developed its process and materials through a SMART Feasibility Award from the UK Department of Trade and Industry. The aim of the project was to demonstrate the feasibility of printing transparent conducting oxides using inkjet technology to achieve electrical and optical functionality. As part of the project, PTL investigated a number of materials, including ITO. However, there are significant cost advantages in using alternative transparent conducting oxide materials. Inkjet printing offers more freedom of choice of materials because it removes the need for etching to produce patterned layers. Antimony Tin Oxide – The Material of Choice该公司选择氧化胰岛锡（ATO）作为符合所需成本和性能标准的首选材料。由Keeling＆Walker（K＆W）制造，将氧化二锡氧化物加工成粉末，然后设计成水性悬浮液，其中锑锡氧化物氧化物纳米颗粒稳定。欧洲杯猜球平台发现各种添加剂可以帮助颗粒的放置，从而改善光学性能和电性能。欧洲杯猜球平台 涂层特性然后，PTL研究人员使用按需打印机直接使用透明的导电氧化物纳米粒子油墨直接编写来自数据文件的导电功能，并实现了厚度约为220nm的极其均匀的导电涂层。在退火前对膜的检查表明它们是由纳米颗粒簇组成的，该纳米颗粒的簇是由大小从12-40nm的凝结组成的。欧洲杯猜球平台在退火之前，由于材料中的孔隙率和不良的传导路径，膜具有高电阻。退火产生了更加均匀的微结构并增加了电导率，从而使电阻值约为1-2K ohm/sq。预计材料，流体和沉积的进一步工作将产生更欧洲杯足球竞彩好的性能。覆盖较大区域的薄膜中的一些厚度变化（大于2厘米2）have been seen - but these are believed to be associated with jetting deposition and regional mass transfer of particulates during solvent evaporation and forced air-drying. Areas for Continued ResearchThe antimony tin oxide thin films produced in this way have already demonstrated conductivity and optical transmission characteristics suitable for some applications. Optical transmission, measured in the green region of the, visible spectrum at 550nm, was greater than 95%. Continuing research has shown that these properties can be improved upon, and PTL and K&W are working to improve the starting nanopowder, processing route and drying process. Work on the drying and annealing technology, being carried out by PTL, in collaboration with Nottingham Trent University, aims to print transparent conducting oxides on a variety of substrates, including glass, silicon and flexible plastics. Improving materials deposition and annealing will improve the electrical transfer paths without adversely affecting the optical performance. 与溅射的ITO电影相比，直接写的ATO电影产生的批量膜平滑且均匀，平均粗糙度为3nm。使用Zygo光学干涉仪制作的膜的表面曲线表明，直接书面膜与溅射的ITO膜相当。显然，这些可打印的喷墨式氧化氧化物具有所需的特性，并且可能是一个重要的直接写作材料成功，但这取决于PTL与行业的合作伙伴关系。欧洲杯足球竞彩PTL及其许多合作者已获得DTI链接奖，以开发印刷透明导电技术在IFM公司开发的显示中的应用。PTL还着手进行了许多其他项目，这些项目充分利用了掩盖层，高性能标记系统，绝缘体，医疗传感器，涂料和3D结构的优势。 在光伏胶片中的潜在使用喷墨胶片One particularly interesting application area is photovoltaics. Thin film solar cell technology is in the early stages of commercial production, and an obvious problem is that the high cost of crystalline silicon wafers dictates the need for cheaper materials to make up the other parts of the cells to keep costs down. A transparent conductive film forms the front contacts of thin film cells, where the current is taken away. This could potentially be inkjet printed using antimony tin oxide ink, which could therefore bring down the capital equipment and materials costs of production, and make the new solar cells a much more viable commercial proposition. |