Highly selective nanostructure sensors and methods of detecting target analytes
Inventors
Motayed, Abhishek • Aluri, Geetha • Davydov, Albert V. • Rao, Mulpuri V. • Oleshko, Vladimir P. • Bajpai, Ritu • Zaghloul, Mona E.
Assignees
George Washington University • George Mason University • National Institute of Standards and Technology NIST • University of Maryland College Park • United States Department of Commerce
Publication Number
US-9476862-B2
Publication Date
2016-10-25
Expiration Date
2033-04-12
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Abstract
A nanostructure sensing device comprises a semiconductor nanostructure having an outer surface, and at least one of metal or metal-oxide nanoparticle clusters functionalizing the outer surface of the nanostructure and forming a photoconductive nanostructure/nanocluster hybrid sensor enabling light-assisted sensing of a target analyte.
Core Innovation
The invention relates to sensor devices comprising semiconductor nanostructures functionalized with metal and/or metal-oxide nanoparticles or nanoclusters to create photoconductive nanostructure/nanocluster hybrid sensors enabling light-assisted sensing of target analytes. These sensors operate at room temperature by photoenabled sensing, avoiding the high temperatures required by conventional metal-oxide sensors, and offer high selectivity and sensitivity.
The problem being addressed is the lack of selectivity, high operating temperatures, long response times, and limited applicability of conventional metal-oxide based gas sensors. Traditional sensors require high temperatures (≧250°C) for operation, suffer from poor discrimination between chemically similar analytes, have slow response and recovery times, and do not reliably operate in air, limiting real-world applicability. Additionally, interpreting results from mats of nanowires is difficult due to complex inter-wire conduction. There is a need for a sensor device that overcomes these deficiencies by enabling selective, rapid, low-power, and reliable detection of chemicals, including hazardous compounds such as explosives, at room temperature.
The disclosed sensor devices utilize a semiconductor nanostructure backbone (e.g., GaN, InN, ALGaN, ZnO, InAs) functionalized with metal-oxide and/or metal nanoparticle clusters that act as photocatalysts or catalysts to selectively adsorb and react with target analytes. This functionalization changes the surface potential and carrier dynamics under illumination, thereby modulating conductivity. The use of light (e.g., UV) enables fast, reversible, and sensitive detection at temperatures well below 100°C, including ambient temperature. Multicomponent nanoclusters enable tailored selectivity by combining different adsorption profiles, suppressing interference from competing analytes. The architecture supports multi-analyte detection and is compatible with large-scale manufacturing using standard microfabrication techniques.
Claims Coverage
The independent claims cover two main sensor device configurations with their inventive features focused on the semiconductor nanostructure functionalized with metal and metal-oxide nanoparticles enabling selective, photoconductive, light-assisted detection of target analytes.
Nanostructure sensor with metal-oxide and metal nanoparticle functionalization for selective analyte detection
A multi-analyte sensor comprising a semiconductor nanostructure disposed on a substrate, functionalized with first metal-oxide nanoparticles possessing a first adsorption profile and second metal nanoparticles possessing a second adsorption profile. The target analyte preferentially adsorbs on the metal-oxide nanoparticles and an interfering analyte preferentially adsorbs on the metal nanoparticles. The sensor exhibits an output change (current, voltage, or resistance) upon detection of the target analyte under light, enabling detection within carrier gases such as air, nitrogen or argon. Semiconductor and nanoparticle materials are specified, with capability to detect alcohol and aromatic compound vapors at temperatures below about 100°C, with rapid response and recovery times.
Photoconductive nanostructure/nanocluster hybrid sensor enabling light-assisted sensing
A nanostructure sensing device comprising a semiconductor nanostructure functionalized with both metal and metal-oxide nanoparticle clusters forming multicomponent clusters. The device has a bandgap relationship where the nanoparticle clusters have equal or lower bandgap than the nanostructure. It enables light-assisted selective detection of a target analyte preferentially adsorbing on one nanoparticle type, and an interfering analyte on the other, within carrier gases including air, nitrogen or argon. The sensor exhibits increased conductivity upon exposure to the analyte in the presence of radiation such as UV excitation, and operates at temperatures below about 100°C with fast response and recovery times.
The independent claims cover nanostructure-based sensor devices functionalized with specific metal and metal-oxide nanoparticle combinations allowing selective, room-temperature, light-assisted detection of target analytes with rapid response and recovery, applicable in various carrier gases, and utilizing standard semiconductor materials and nanoparticle compositions.
Stated Advantages
Light-induced room-temperature sensing enables low-power operation, longer sensor lifetime, and fast on/off capability compared to conventional sensors requiring high temperatures.
Highly selective sensing allowing discrimination between closely related compounds, such as distinguishing toluene from other aromatic compounds.
Wide sensing concentration range from 50 parts per billion to 1%.
Fast response and recovery times, generally less than 180 seconds, and preferably less than 75 seconds.
Reliable and repeatable operation with stable detection in air and other carrier gases.
Economical fabrication using standard microfabrication and sputtering techniques suitable for large-scale manufacturing and multi-analyte single-chip sensors.
Documented Applications
Environmental monitoring including detection of industrial pollutants, poisonous gases, chemical fumes, and volatile organic compounds (VOCs) in air at room temperature.
Explosive threat detection including sensitive and selective detection of nitro-aromatic explosives such as TNT, dinitrotoluene, nitrotoluene, dinitrobenzene, and nitrobenzene at room temperature in air.
Industrial monitoring and process control such as monitoring gases and chemical leaks in oil refineries and manufacturing plants.
Indoor air quality and safety monitoring in residential and commercial buildings for adaptive ventilation control, detection of harmful VOCs and gas leaks.
Law enforcement applications including breath analyzers for alcohol detection and integration into handheld or mobile devices for personal monitoring.
Defense and security applications for monitoring public spaces and personnel for deliberate release of harmful chemicals, explosives, and terrorist threats.
First responder tools providing rapid, low-power, handheld detection of hazardous chemicals during disaster and emergency situations.
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