Graphitic Carbon Nitride Sensor with Functionalized Graphite
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Solution Overview
Problem
Current gas sensors, particularly those using graphitic carbon nitride, face limitations due to fast recombination rates of photoinduced charge carriers, which hampers their effectiveness as photocatalysts and sensors, especially in detecting gases like oxygen.
Innovation Solution
A sensor system incorporating a functionalized graphitic material, such as reduced graphene oxide or holey reduced graphene oxide, combined with uncondensed graphitic carbon nitride, where electromagnetic energy is applied to enhance conductance and measure analyte presence, utilizing a photoredox mechanism for improved sensitivity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If graphitic carbon nitride is used as a photocatalyst for gas sensing, then photoexcitation capability is improved, but charge carrier recombination rate increases
Solution Approach 1:
The patent introduces a functionalized graphitic material as an intermediary component between the graphitic carbon nitride photocatalyst and the analyte. This intermediary facilitates charge separation and transfer, reducing the recombination rate of photoinduced charge carriers while maintaining photoexcitation capability. The functionalized graphitic material acts as a mediator that improves overall sensor reliability by managing charge carrier dynamics.
Solution Approach 2:
The patent creates a composite sensing material by combining graphitic carbon nitride with functionalized graphitic material. This composite structure leverages the photoexcitation properties of carbon nitride while the functionalized graphitic component provides enhanced charge carrier management. The synergistic combination resolves the contradiction by integrating materials with complementary properties that simultaneously achieve high photoexcitation and low recombination rates.
2Measurement precision
If electromagnetic energy is applied to increase conductance, then sensitivity to analyte is improved, but energy consumption increases
Solution Approach 1:
The patent utilizes parameter changes in the conductance of the sensing material in response to electromagnetic energy application. By monitoring the change in conductance parameter under controlled electromagnetic excitation, the system achieves high sensitivity to analyte presence. The functionalized graphitic material's conductance responds logarithmically to analyte concentration, allowing precise measurement while optimizing energy input levels to balance sensitivity with energy consumption.
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 achieves logarithmic proportional response to oxygen concentrations, significantly increasing conductance under UV irradiation, and demonstrates sensitivity and selectivity for oxygen detection across a wide range, even in humid conditions, with potential for adapting to detect other analytes by modifying the composite material's work function.
Implementation Method 1
Carbon nitride's bandgap (2.7 eV) is beneficial because of its ability to be photoexcited by visible light
Implementation Method 2
Semiconductor photocatalysts are a class of heterogeneous catalysts that utilize photo-generated electron-hole pairs for photoredox catalysis
Implementation Method 3
Catalytic materials provide a receptor function by adsorbing and reacting with certain analytes
Implementation Method 4
changes in the local chemical environment and minute charge transfers are able to effect observable changes in a carbon nanomaterial's electrical properties
Data Source
AI summary
A sensor includes a substrate, a first electrode, a second electrode spaced from the first electrode, and a sensing medium on the substrate between the first electrode and the second electrode. The sensor medium includes a functionalized graphitic material and an uncondensed graphitic carbon nitride disposed upon the functionalized graphitic material. The sensor further includes a system for applying electromagnetic energy to the sensing medium to increase the conductance of the sensing medium, and circuitry including at least one measurement system in operative connection with the sensor to measure a variable relatable to the conductance of the sensing medium which is dependent upon the presence of an analyte to be detected.