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Vladimir Bulović. Ho, John C., 1980- Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science 2010-03-24T20:38:22Z 2010-03-24T20:38:22Z 2009 2009 http://hdl.handle.net/1721.1/52795 547286227 Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Cataloged from student submitted PDF version of thesis. Includes bibliographical references. As the U.S. is engaged in battle overseas, there is an urgent need for the development of sensors for early warning and protection of military forces against potential attacks. On the battlefields, improvised explosive devices (IEDs) have resulted in 54% of all coalition deaths in Iraq and 59% in Afghanistan. The U.S. military has responded with an intensive program of technology development, spending $12.4 billion over the past three years on counter-IED equipment, technology R&D, training, and other measures through the Joint Improvised Explosive Device Defeat Organization (JIEDDO). Snifing"technology, based on fluorescent polymers, has emerged as one of the most sensitive tools in the military's explosives-detecting arsenal. Fluorescent polymer sensors have demonstrated effective ultra-trace, vapor-phase detection of trinitrotoluene (TNT) at security checkpoints and during vehicular sweeps, achieving sensitivity levels comparable to the canine nose. In this sensor scheme, a large contribution to the noise signal is the inefficient transduction of the polymer's chemically sensitive, photoluminescent signal into an electrical signal. The poor optical coupling of the polymer's photoluminescence into a photodetector, reduces the signal-to-noise ratio (SNR) and overall sensor performance. In this work we have developed a novel transduction mechanism and device structure that enable more efficient photon-to-electron conversion resulting in direct transduction of the chemical signature into an electrical signal. Device models detailing the physical processes of device operation will be presented along with supporting experimental evidence. (cont.) In addition, detection of as little as 1 picogram of TNT has been demonstrated. Ultimately, this work results in a solid-state sensor platform that can be readily engineered to accept any chemosensitive fluorescent polymer for a variety of ultra-trace sensing applications with potential uses in the medical diagnostic, industrial processing, environmental, and defense industries. by John C. Ho. Ph.D. 252 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Electrical Engineering and Computer Science. Organic lateral heterojunction devices for vapor-phase chemical detection Thesis application/pdf Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="fe4a7720-59c5-4b3d-8edb-5108d5ba64ba"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Organic lateral heterojunction devices for vapor-phase chemical detection</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2009</PublicationDate> <Authors> <Author> <DisplayName>Ho, John C., 1980-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Electrical Engineering and Computer Science.</Keyword> <Abstract>As the U.S. is engaged in battle overseas, there is an urgent need for the development of sensors for early warning and protection of military forces against potential attacks. On the battlefields, improvised explosive devices (IEDs) have resulted in 54% of all coalition deaths in Iraq and 59% in Afghanistan. The U.S. military has responded with an intensive program of technology development, spending $12.4 billion over the past three years on counter-IED equipment, technology R&D, training, and other measures through the Joint Improvised Explosive Device Defeat Organization (JIEDDO). Snifing"technology, based on fluorescent polymers, has emerged as one of the most sensitive tools in the military's explosives-detecting arsenal. Fluorescent polymer sensors have demonstrated effective ultra-trace, vapor-phase detection of trinitrotoluene (TNT) at security checkpoints and during vehicular sweeps, achieving sensitivity levels comparable to the canine nose. In this sensor scheme, a large contribution to the noise signal is the inefficient transduction of the polymer's chemically sensitive, photoluminescent signal into an electrical signal. The poor optical coupling of the polymer's photoluminescence into a photodetector, reduces the signal-to-noise ratio (SNR) and overall sensor performance. In this work we have developed a novel transduction mechanism and device structure that enable more efficient photon-to-electron conversion resulting in direct transduction of the chemical signature into an electrical signal. Device models detailing the physical processes of device operation will be presented along with supporting experimental evidence.</Abstract> <Abstract>(cont.) In addition, detection of as little as 1 picogram of TNT has been demonstrated. Ultimately, this work results in a solid-state sensor platform that can be readily engineered to accept any chemosensitive fluorescent polymer for a variety of ultra-trace sensing applications with potential uses in the medical diagnostic, industrial processing, environmental, and defense industries.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>