Atomic-Thin 2D Material Gas Sensor for Food Freshness
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Solution Overview
Problem
Existing methods for determining food freshness, such as 'sell by' tags and gas sensors, are inaccurate and impractical for consumer use due to their reliance on chemical reactions, high cost, and bulkiness, leading to potential consumption of spoiled meat or unnecessary discard of fresh meat.
Innovation Solution
A portable system utilizing an atomic-thin two-dimensional material-based gas sensor that applies a constant current and measures changes in compliance voltage to detect gases emitted by spoiled food, transmitting this data to a remote device for real-time freshness determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional gas sensors are used for food freshness detection, then gas detection capability is provided, but the devices are bulky, expensive, and have low sensitivity
Solution Approach 1:
The patent employs atomic-thin two-dimensional materials (graphene, MoS2, WS2, WSe2) as the sensing element, replacing conventional bulky sensor structures. These 2D materials provide high surface area to volume ratio, enabling enhanced gas detection sensitivity in a compact form factor that can be integrated into portable devices.
Solution Approach 2:
The patent utilizes composite material structures combining 2D materials with appropriate substrates and functional layers. This composite approach optimizes both the sensitivity of gas detection and the mechanical stability of the device, resolving the contradiction between high sensitivity and compact form factor.
2Ease of manufacture
If metal-oxide nanoparticle sensors are used, then cost is reduced, but the sensors easily malfunction due to strong chemical reactions with spoiled meat gases
Solution Approach 1:
The patent changes the fundamental material parameter from conventional metal-oxide nanoparticles to atomic-thin two-dimensional materials. This parameter change fundamentally alters the sensing mechanism, reducing unwanted chemical reactions with spoilage gases while maintaining cost-effectiveness through simplified device architecture and reduced material costs.
Solution Approach 2:
The patent employs inexpensive 2D materials that can be easily replaced if needed, providing a cost-effective solution that balances reliability with affordability. The simplified sensor structure using 2D materials reduces manufacturing complexity and cost compared to conventional high-precision sensors.
3Measurement precision
If chemical reaction-based sensing is used, then detection capability is achieved, but the methods are inaccurate for determining food freshness
Solution Approach 1:
The patent replaces chemical reaction-based sensing with physical sensing mechanisms using 2D materials that detect gas presence through changes in electrical properties (conductance, resistance). This substitution eliminates the interference from strong chemical reactions while maintaining detection accuracy, as the 2D materials respond to gas molecules through physical adsorption and charge transfer mechanisms rather than bulk chemical reactions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides an accurate, cost-effective, and portable means to determine food freshness, reducing food waste and enhancing food safety by allowing for quick and reliable detection of spoilage gases.
Implementation Method 1
The atomic-thin two-dimensional material has a resistance; sense a change in the compliance voltage based on exposing the atomic-thin two-dimensional material to a gas
Data Source
AI summary
A system for determining food freshness includes a gas sensor including an atomic-thin two-dimensional material; an instrumentation circuit configured to supply a constant current to the atomic-thin two-dimensional material; an analog-to-digital converter configured to convert a voltage to a digital signal representative of the voltage; a transceiver configured to transmit the digital signal to a remote device; a processor; and a memory. The memory includes instructions stored thereon, which, when executed by the processor, cause the system to: apply a constant current across the atomic-thin two-dimensional material; determine a compliance voltage across the atomic-thin two-dimensional material; sense a change in the compliance voltage based on exposing the atomic-thin two-dimensional material to a gas; transmit the sensed change to the remote device; determine if the sensed change represents a first value greater than a threshold value; and determine an amount of the gas based on the determination.