"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.

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University of Toledo
United States
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