Collaborative Research: Single walled nanotubes and Graphene based multiplexed sensors for hypergolic fuel detection

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”项目目标：准确可靠地检测联氨及其衍生物等自燃燃料在导弹防御机构、航空、国土安全以及化学工业中至关重要。更重要的是，这些传感器需要在低温下工作，尽管大多数广泛使用的化学传感器在中等高温下工作。已知单壁碳纳米管和单层石墨烯对室温下局部化学环境的变化表现出极端的敏感性。本提案提出了一种制造传感器平台的方法，该平台由碳纳米管阵列和具有系统修饰表面特性的石墨烯组成。知识优势：提出的新型传感器机制是基于碳纳米管和石墨烯热电电压的转导。纳米管和石墨烯的串联集成可以弥补每种结构的局限性。人们认为，与传统的电阻响应相比，热电响应的信息量更大，灵敏度更高。一个公共加热器为所有传感器元件的热电电压转换提供了必要的温度梯度，为多路复用提供了简单的手段。本研究的主要目的是通过了解基于碳纳米管和石墨烯的气体传感器的选择性和传感性能的机制来提高其传感性能。热电电压测量可以使用简单的接口到标准电子设备，而不需要通过每个传感器灯丝的激励电流。提出的研究将导致基于(i)碳纳米管网络和石墨烯的新型多路复用平台（ii）基于热电电压转导的传感技术的优越气体/化学传感器的制造。此外，该研究在许多方面都具有革命性，例如石墨烯纳米带的控制形成，以及通过简单的拾取和放置技术在测试平台上控制石墨烯的沉积。该方法的关键部分包括静电工具对石墨烯的操纵。从这项研究中获得的知识将有益于未来的纳米电子学和纳米科学。更广泛的影响：拟议的项目将具有科学和教育方面的影响。科学影响与进一步了解支撑高性能制造技术的基本原理，表面气体和化学物质的相互作用以及表面改性对碳纳米管和石墨烯灵敏度的影响有关。结合路易斯维尔大学和托莱多大学的努力，将启动新的研究培训和外展活动教育计划。将资助两名研究生在两个研究实验室之间交流研究知识/设备。外展计划包括让高中社区参与研究、研讨会和准备奖学金。这些外展活动将为路易斯维尔/肯塔基州和托莱多/俄亥俄州的代表性不足和女性学生社区提供一切机会。研究人员计划开发一本教科书和一本关于进步纳米科学的通俗书籍，这可以成为对下一代非常有益的资源。这些活动将提高公众对纳米技术和当前纳米材料技术的认识。研究成果将通过在两所院校共享课程材料，整合到本科和研究生课程中。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Project Objective: Accurate and reliable detection of hypergolic fuels such as hydrazine and its derivatives is vital in missile defense agency, aviation, homeland security, and chemical industry. More importantly these sensors need to be operated at low temperatures though most of the widely used chemical sensors operate at moderately high temperatures. Single walled carbon nanotubes and monolayer graphene are known to exhibit extreme sensitivity towards the changes in the local chemical environment at room temperatures. This proposal presents a methodology to fabricate a sensor platform consisting of arrays of carbon nanotubes and graphene with systematically modified surface properties. Intellectual Merit:The proposed novel sensor mechanism is based on the transduction of thermoelectric voltage of carbon nanotubes and graphene. Integration of nanotubes and graphene in tandem can complement for the limitations of each structure. Thermoelectric power is believed to be more informative and sensitive compared to conventional resistive response. A common heater provides the necessary temperature gradient for the transduction of thermoelectric voltage for all the sensor elements providing easy means for multiplexing. The main thrust of this proposal is to improve the sensing properties of carbon nanotube and graphene based gas sensors by understanding the mechanism underpinning the selectivity and sensing properties. Thermoelectric voltage measurement would enable the use of simple interface to standard electronics without need of an excitation current through each sensor filament. The proposed research will lead to fabrication of superior gas/chemical sensors based on (i) a novel platform of multiplexing of carbon nanotube networks and graphene (ii) a sensing technique based on the transduction of thermoelectric voltage. Also the proposed research is transformative in many ways such as controlled formation of Graphene Nano-ribbons and controlled depositions of graphene by a simple pick and place technique onto test platforms. The key component of the proposed method includes manipulation of graphene by electrostatic tools. The knowledge obtained from this research will be beneficial in future nanoelectronics and nanoscience beyond this project. Broader Impact:The proposed project will have both scientific and educational impact. The scientific impact is associated with the furthering of the fundamental understanding of principles underpinning the fabrication techniques towards high performance, interaction of gases and chemicals at surfaces, and surface modification effects on sensitivity of carbon nanotubes and graphene. Combining the efforts at The University of Louisville and The University of Toledo, new education programs for research training and outreach activities will be initiated. Two graduate students will be sponsored to exchange research knowledge/facilities between the two research laboratories. The outreach programs include involvement of high school communities in research, workshops, and preparation for scholarships. These outreach activities will provide every opportunity for underrepresented and female student communities in Louisville/Kentucky and Toledo/Ohio. The investigators plan to develop a text book and a popular book in progressive nanoscience that can be highly beneficial resources for future generation. These activities will enhance the public awareness about nanotechnology and current nanomaterials technology. The research outcomes will be integrated into the undergraduate and graduate curriculum by sharing the course materials at both institutions.