Glamazda A.Y.,Ukrainian Academy of Sciences |
Karachevtsev V.A.,Ukrainian Academy of Sciences |
Euler W.B.,University of Rhode Island |
Levitsky I.A.,University of Rhode Island |
Levitsky I.A.,Emitech, Inc
Advanced Functional Materials | Year: 2012
An anisotropic carbon nanotube (CNT)-polymer composite for bolometric applications in the mid-IR spectral range (2.5-20 μm) is studied. Composite alignment in conjunction with non-uniform distribution of CNTs in the polymer matrix allows for a significant enhancement of the temperature coefficient of resistance (0.82% K -1) with respect to uniform composite (0.24% K -1). As a result a responsivity of ≈ 500 V W -1 is reached, which is the highest for CNT-based bolometers reported to date. Such remarkable optical and thermal characteristics are explained in terms of fluctuation tunneling theory taking into account the composite anisotropy and the gradient of the CNT concentration. Flatness of the photoresponse in the broad spectral mid-IR range and enhanced responsivity provide a great potential for the use of such novel composite for applications in IR spectroscopy and thermal imaging. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Emitech, Inc | Date: 2010-02-08
An optochemical detector for detecting various chemical compounds and comprising a flow cell incorporating the sensory element constructed of an organic-inorganic emissive nanocomposite which luminescence spectral response is specific to exposed target vapors and particulates. The change in the luminescent spectral response is measured during this exposure. The detector is equipped with air-jet sampling system functioning in real-time mode for delivery of vapors and particulates to sensory element.
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 729.83K | Year: 2006
Emitech, Inc proposes to design and develop a novel, highly sensitive and selective optochemical sensor array based on organic-inorganic nanocomposites for real-time, standoff detection of vehicle-borne IEDs. The main principle of detection, as distinct from other luminescent chemical sensors, is based on the emission quenching of sensory polymers entrapped into mesoporous photonic crystal (or microcavity). The unique nanodevice structure will provide a large interfacial surface between the sensory material and the analytes leading to the highest sensitivity, which is critical for rapid detection (dwell time is on the order of seconds) of low vapor pressure chemicals, like explosives. In Phase I we performed a feasibility study and proved the proposed concept by demonstrating that emission quenching is accompanied by a spectral shift when sensory polymers entrapped in the unique microcavities. This novel effect is critical to the development of sensor arrays possessing high selectivity and sensitivity to explosive vapors. In Phase II the demonstrated new technology will be further developed and optimized to fabricate a prototype sensor array for Army missions and commercial applications. A sensor array will be placed on the tip of the lightweight telescopic probe/console (length up to 20 m and longer) which can be mounted to a HMMWV or other armor vehicles. Also, this device can be installed on the small robotic vehicle or mini unmanned plane (standoff distance is of 100 m) teleoperated from a HMMWV.
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 69.45K | Year: 2009
We propose to study and develop a novel, highly sensitive and selective optochemical portable detection system for stand-off detection (more than 300 m) of IED hazard. In Phase-I, the feasibility of the concept will be demonstrated at a distance of 150 m for major nitro-explosives (TNT, RDX, PETN) deposited on the surface with concentration ~ ng/mm2. The two main transduction mechanisms will be tested: polymer fluorescence quenching and spectral shift of resonance peak of nanoporous Si microcavity infiltrated with imprinted silica. The unique nanodevice structure provides a large surface area between the sensory material and the analytes leading to the highest sensitivity, which is critical for fast detection (response time is about several seconds) of low vapor pressure explosives. Stand-off sensing will be provided by ballistic delivery in conjunction with laser excitation/interrogation followed by the signal processing. The proposed technology is highly innovative and promising for future developments. We have demonstrated some of the key issues for its implementation, thus the successful completion of Phase-I is highly possible. In Phase-II, the developed prototype will be capable of detecting IEDs from the stand-odd distance of more than 300 meters in the presence of common operational interferences.
Ong P.-L.,Emitech, Inc |
Levitsky I.A.,Emitech, Inc |
Levitsky I.A.,University of Rhode Island
Energies | Year: 2010
We present a review of the emerging class of hybrid solar cells based on organic-semiconductor (Group IV, III-V), nanocomposites, which states separately from dye synthesized, polymer-metal oxides and organic-inorganic (Group II-VI) nanocomposite photovoltaics. The structure of such hybrid cell comprises of an organic active material (p-type) deposited by coating, printing or spraying technique on the surface of bulk or nanostructured semiconductor (n-type) forming a heterojunction between the two materials. Organic components include various photosensitive monomers (e.g., phtalocyanines or porphyrines), conjugated polymers, and carbon nanotubes. Mechanisms of the charge separation at the interface and their transport are discussed. Also, perspectives on the future development of such hybrid cells and comparative analysis with other classes of photovoltaics of third generation are presented. © 2010 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland. Source