SNM: Customized Inkjet Printing of Graphene-Based Real-time Water Sensors

用于实时监测水中污染物（如有毒重金属离子）的低成本传感器可以提供污染的早期预警，从而改善饮用水安全和保护公众健康。因此，探索基于石墨烯的水传感器平台，以快速，灵敏和选择性地检测各种水污染物，克服当前传感技术的局限性，如检测速度慢和灵敏度不足。然而，这种传感器系统的商业化受到其相对较高的制造成本的限制，因为批量加工涉及传统的光刻电极制造和多个手工电极后制造过程。该奖项探索了一种低成本定制喷墨打印工艺，用于制造基于石墨烯的水传感器。这项研究需要设计各种油墨，并修改标准喷墨打印工艺，以连续生产完整的传感器系统。纳米水传感系统的高通量制造降低了成本，提高了市场接受度。研究结果为基材选择和处理提供了基本原理，为生产适合喷墨印刷的各种油墨提供了可扩展的方法，并为定制喷墨印刷提供了工艺模型。项目成果可用于许多其他应用，如太阳能电池、锂离子电池和超级电容器，从而实现各种可打印电子设备的低成本制造。该项目通过实践研究经验、课程模块和丰富现有课程，对包括妇女和少数民族在内的不同学生群体进行可扩展纳米制造、纳米器件设计和实时水传感技术方面的培训。传感器平台基于场效应晶体管结构，还原氧化石墨烯作为传感通道，金纳米粒子作为选择性化学探针的锚定位点。喷墨打印的一个主要挑战是为特定设备或系统架构定制喷墨打印过程。定制包括设计合适的油墨，修改标准印刷工艺参数，以及集成不同规模的组件。研究小组的目标是通过探索整个基于石墨烯的传感器系统的喷墨打印来缩小这一知识差距，从而通过高吞吐量卷对卷的传感器设备的纳米制造来实现大规模生产，这将导致低成本。研究了所有传感器组件（电极、传感材料和探针）墨水的可扩展纳米制造，以及它们的打印和集成到水传感器系统中，以及选择和处理聚合物基材和定制喷墨打印参数的方法。通过与a.o.史密斯公司和NanoAffix科学有限责任公司的合作，传感器的性能在工业测试平台上得到了验证。该项目为石墨烯水传感器系统和其他柔性电子系统提供了一个低成本、高产量的可扩展纳米制造平台，可以很容易地由工业合作伙伴商业化。

Low-cost sensors for real-time monitoring of contaminants in water, such as toxic heavy metal ions, could provide early warning of contamination, thereby improving drinking water safety and protecting public health. A graphene-based water sensor platform is thus explored for rapid, sensitive, and selective detection of various water contaminants, overcoming limitations of current sensing technologies such as slow detection and inadequate sensitivity. However, the commercialization of such a sensor system is limited by its relatively high manufacturing cost due to the batch processing that involves traditional lithographic electrode fabrication and multiple manual post-electrode fabrication processes. This award explores a low-cost customized inkjet printing process for manufacturing of graphene-based water sensors. The research entails engineering various inks and modifying the standard inkjet printing process to produce the complete sensor system, continuously. High throughput manufacturing of the nano-enabled water sensing systems reduces their cost and enhances market acceptance. The research outcomes provide the rationale for substrate selection and treatment, scalable methods for producing various inks suitable for inkjet printing, and process models for customized inkjet printing. Project results could be used for many other applications such as solar cells, lithium-ion batteries, and supercapacitors, enabling low-cost manufacturing of a wide range of printable electronic devices. The project trains diverse student populations including women and minorities on scalable nanomanufacturing, nanodevice design and real-time water-sensing technologies through hands-on research experience, a course module, and enriching existing curricula.The sensor platform is based on a field-effect transistor structure with reduced graphene oxide as the sensing channel and gold nanoparticles as anchoring sites of selective chemical probes. A major challenge for inkjet printing is the customization of the inkjet printing process for a specific device or system architecture. Customization involves engineering suitable inks, modifying the standard printing process parameters, and integrating components at different scales. The research team aims to close this knowledge gap by exploring inkjet printing of the entire graphene-based sensor system to enable the large-scale production via high throughput roll-to-roll nanomanufacturing of the sensor devices, which should result in low cost. The scalable nanomanufacturing of inks for all sensor components: electrode, sensing material, and probe, and their printing and integration into water sensor systems are investigated, together with methods for selecting and treating polymer substrates and customizing inkjet printing parameters. The sensor performance is validated in industrial testbeds through collaboration with A. O. Smith Corporation and NanoAffix Science, LLC. The project leads to a low-cost, high-yield scalable nanomanufacturing platform for graphene-based water sensor systems and other flexible electronic systems that can be readily commercialized by industrial partners.