Sensors with capacitive transduction via metamaterials for gas detection
Inventors
CHILDRESS, Anthony • Busnaina, Ahmed
Assignees
Northeastern University Boston
Publication Number
US-12235236-B2
Publication Date
2025-02-25
Expiration Date
2042-05-31
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Abstract
Devices and methods for detecting an analyte in a gas involve the use of plasmonic excitation of a nanostructured sensing element that is tuned to absorb at a narrow bandwidth specific for light absorbed by the analyte. The sensing element can be used as a capacitive or inductive element in a circuit.
Core Innovation
The invention provides devices and methods for detecting an analyte in a gas by utilizing the plasmonic excitation of a nanostructured sensing element, which is tuned to absorb at a narrow bandwidth that matches a specific absorbance characteristic of the targeted analyte. This sensing element functions as a capacitive or inductive element in an electronic circuit, where the local field established by plasmonic modes affects the measurable capacitance or inductance.
When sample gas passes through the flow path of the sensor, a light source emits light at a wavelength band overlapping with the absorbance spectrum of the analyte. The analyte absorbs some of this incident light as it traverses the flow path, leading to a measurable alteration of the capacitance or inductance in the sensor element. This change is detected electronically and can trigger transmission of a representative signal for further analysis or alert.
The problem addressed by the invention is the need for gas detectors that are readily deployable and suitable for widespread monitoring in diverse environments, overcoming the limitations of conventional sensors that rely on photodetectors, monochromators, complex optical setups, or costly fabrication methods. By using a nanostructured array of conductive nanoelements encapsulated within a dielectric material, and leveraging the plasmonic modes tuned to the analyte's absorbance, the device achieves gas detection through direct modulation of electronic circuit parameters without requiring additional optical components.
Claims Coverage
The patent contains three independent claims encompassing core inventive features regarding a sensor device, a detection method, and a detection system involving plasmonic nanostructures for gas detection.
Sensor device utilizing plasmonic nanostructures to detect changes in capacitance or inductance in response to analyte-specific optical absorption
A sensor device includes: - A housing with a flow path for sample gas - A light source within the housing that emits light with an emission wavelength band overlapping with an absorbance spectrum or portion thereof of a selected analyte - A sensing element made of a nanostructure array of conductive nanoelements attached to a substrate and encapsulated in a dielectric material, where the nanostructure and dielectric are tuned so their plasmonic absorption band overlaps with the absorbance spectrum or portion of the analyte - The local field from plasmonic modes in the nanostructure array affects the capacitance or inductance, which is electronically detected
Method for detecting presence of an analyte via measurement of capacitance or inductance modulation using the sensor device
A method comprising: 1. Providing the aforementioned sensor device 2. Establishing a baseline capacitance or inductance when no analyte is present in the flow path 3. Detecting a change in capacitance or inductance when the analyte is present in the flow path 4. Transmitting a signal representative of this change to electronic circuitry and/or a processor
System for gas detection combining the sensor device with a gas sample transport and processing
A system comprising: - The sensor device with plasmonic nanostructure sensing element - A pump and/or inlet to transport the gas sample through the flow path - A processor that detects changes in capacitance or inductance of the sensor element when analyte is present and transmits information indicative of analyte detection to a receiver or over a network
In summary, the independent claims cover a sensor device exploiting plasmonic nanostructures tuned for analyte-specific absorption to induce measurable electrical changes, a method for using such a device to detect gas analytes, and a complete system integrating sample handling and electronic signal processing for gas detection.
Stated Advantages
The technology operates without requiring photodetectors, monochromators, optical filters, or prisms.
It allows for selective, analyte-specific detection by tuning plasmonic absorption to narrow bandwidths.
The sensor can be fabricated at low cost using scalable nanoprinting and self-assembly methods.
The sensing element can be encapsulated in a dielectric material for protection against moisture, oxidation, and poisoning by reactive gases.
The device is compact, robust, and contains no moving parts, enabling broad deployment and mass production.
Operation depends on direct electronic transduction from plasmonic excitation, rather than photoelectric methods, for signal output.
It is adaptable for detection of a wide range of gases by tailoring the nanostructure geometry and composition.
The design enables cost-effective monitoring over large areas and in diverse environments, including hazardous or harsh areas.
Documented Applications
Detection of gas molecules that are difficult to detect by chemical means, including hydrocarbons (e.g., methane, ethane, propane, butane), hydrogen, ammonia, and hydrogen sulfide.
Monitoring of gas leaks, including those in environments hazardous to traditional catalyst-based detectors.
Monitoring of gases for public safety in locations such as oil or gas rigs, refineries, analytical labs, manufacturing facilities, public transport areas, storage or distribution facilities, vehicles, hazmat areas, and residences.
Detection in military applications and civil aviation.
Use in environments where monitoring for oxygen depletion or flammable/toxic gases is required.
Application for the detection and monitoring of methane for storage, natural gas handling, and climate change studies.
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