2H to 1T phase based transition metal dichalcogenide sensor for optical and electronic detection of strong electron donor chemical vapors
Inventors
Friedman, Adam L. • Perkins, F. Keith • Culbertson, James C. • Hanbicki, Aubrey T. • Campbell, Paul M.
Assignees
Publication Number
US-10801987-B2
Publication Date
2020-10-13
Expiration Date
2037-07-18
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Abstract
Optical and electronic detection of chemicals, and particularly strong electron-donors, by 2H to 1T phase-based transition metal dichalcogenide (TMD) films, detection apparatus incorporating the TMD films, methods for forming the detection apparatus, and detection systems and methods based on the TMD films are provided. The detection apparatus includes a 2H phase TMD film that transitions to the 1T phase under exposure to strong electron donors. After exposure, the phase state can be determined to assess whether all or a portion of the TMD has undergone a transition from the 2H phase to the 1T phase. Following detection, TMD films in the 1T phase can be converted back to the 2H phase, resulting in a reusable chemical sensor that is selective for strong electron donors.
Core Innovation
The invention provides sensors incorporating transition metal dichalcogenide (TMD) films that undergo a phase change from a 2H semiconducting phase to a 1T metallic phase upon exposure to chemical vapors, particularly strong electron donors. The detection apparatus includes a 2H phase TMD film that transitions to the 1T phase when exposed to strong electron donor vapors. After exposure to an unknown chemical vapor, the phase state of the TMD film is evaluated to determine whether the phase has changed from 2H to 1T, facilitating detection of strong electron donors.
This phase change is reversible, allowing the TMD films in the 1T phase to be converted back to the 2H phase, for example by annealing, thereby enabling a reusable chemical aerosol sensor. The sensors can also determine the phase state using techniques such as Raman spectroscopy, photoluminescence spectroscopy, or electronic resistance measurements. The invention further includes methods for forming the detection apparatus, detection systems, and methods using the TMD films, providing high accuracy and selectivity for detection of strong electron donors.
The problem being solved addresses the limitations of current chemical vapor sensors, which often lack the combination of high sensitivity and selectivity, mechanical flexibility, versatility, and low power consumption. Existing sensor technologies either have poor selectivity, respond to interfering substances like water vapor, require complex fabrication, or have limitations due to size, power consumption, environmental dependencies, or cost. The invention provides an optical and electronic detection method based on the intrinsic 2H to 1T phase transition in TMD films, overcoming these drawbacks for detecting strong electron donor chemical vapors with reusable, low-power, and mechanically flexible sensors.
Claims Coverage
The patent includes one independent method claim covering the detection of strong electron donor chemical vapors using a TMD thin film sensor.
Method for detecting strong electron donor chemical vapors using phase transitions
A method comprising providing at least one sensor with a transition metal chalcogenide thin film having at least one region in the 2H phase; exposing the sensor to an unknown chemical vapor; evaluating whether the 2H phase region has transitioned to the 1T phase; and detecting the presence of a strong electron donor if such a phase change has occurred.
The claims focus on the inventive method of using the 2H to 1T phase transition in TMD thin films for detecting strong electron donor chemical vapors by evaluating the phase change after exposure, enabling detection and reuse by reversing the phase transition.
Stated Advantages
Highly accurate detection of strong electron donors using phase change in TMD films.
Reusable chemical sensors due to reversible phase transition from 1T back to 2H phase.
High sensitivity and selectivity for strong electron donor chemical vapors, avoiding interference from substances like water vapor.
Low power consumption and mechanical flexibility, enabling small, portable, and versatile sensors.
Potential fast response times and multi-modal sensing capability combining optical and electrical detection methods.
Documented Applications
Detection of strong electron donor chemical vapors including toxic industrial chemicals (TICs), chemical warfare agents (CWAs), and explosives.
Use in security, defense, industrial safety, and military applications for monitoring hazardous gases and vapors.
Integration into wearable devices, clothing, gas masks, or pasted on vehicles and equipment for real-time chemical vapor sensing.
Use in handheld or remote sensing systems employing electrical and optical detection methods for environmental monitoring.
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