Two-Dimensional Conjugated COFs for Conductive ppb-Level Gas Sensing
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Solution Overview
Problem
Current chemiresistive sensors face limitations in conductivity, sensitivity, and stability, particularly in covalent-organic frameworks (COFs), which hinder their effectiveness in sensing analytes.
Innovation Solution
Development of covalent-organic frameworks with a fully aromatic and conjugated structure, utilizing metal-coordinated aromatic units linked by aromatic linkers, such as nickelphthalocyanine and pyrene, to enhance conductivity and stability, enabling high intrinsic conductivity and sensitive analyte detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chemiresistive sensors are used, then sensing function is provided, but conductivity is limited
Solution Approach 1:
The patent employs covalent organic frameworks (COFs) with fully aromatic and conjugated structures as composite materials to achieve high intrinsic conductivity. The COFs integrate metal-coordinated aromatic units (such as nickelphthalocyanine) linked by aromatic linkers (such as pyrene), creating a composite structure that combines the advantages of organic materials with enhanced electrical properties, thereby resolving the conductivity limitation of conventional sensors.
Solution Approach 2:
The patent changes the structural parameters of the sensing material by designing COFs with specific aromatic linkers and metal-coordinated units. This parameter change in molecular structure (from conventional materials to fully aromatic conjugated COFs) directly improves conductivity while maintaining the sensing function, thus resolving the contradiction between reliability and device complexity.
2Measurement precision
If conventional chemiresistive sensors are used, then sensing function is provided, but sensitivity is limited
Solution Approach 1:
The COF structure acts as a composite material that enhances sensitivity through its fully aromatic conjugated system, which facilitates electron delocalization and improves analyte detection capability. The specific composition of metal-coordinated aromatic units and aromatic linkers creates a material that is both highly sensitive and stable, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent applies local quality by designing specific functional regions within the COF structure. The metal-coordinated aromatic units (e.g., nickelphthalocyanine) provide localized sensing sites with high sensitivity to specific analytes, while the overall COF framework maintains structural stability. This local functional differentiation enables high sensitivity without compromising overall reliability.
3Reliability
If covalent-organic frameworks with fully aromatic and conjugated structure are developed, then conductivity and sensitivity are improved, but manufacturing complexity increases
Solution Approach 1:
The COF structure is segmented into modular components: metal-coordinated aromatic units (such as nickelphthalocyanine) and aromatic linkers (such as pyrene). These modular segments can be synthesized separately and then assembled through self-organization into the final COF structure. This segmentation simplifies the manufacturing process by breaking down the complex synthesis into manageable steps, thereby reducing overall manufacturing complexity while maintaining high conductivity.
Solution Approach 2:
The patent employs preliminary action by pre-synthesizing the metal-coordinated aromatic units and aromatic linkers before assembling them into the final COF structure. This preliminary preparation of building blocks enables controlled self-assembly and reduces the complexity of the final synthesis step, making the manufacturing process more manageable while achieving the desired high conductivity and sensitivity properties.
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 developed COFs exhibit bulk conductivities up to 2.51×10−3 S/m and demonstrate ultra-low limits of detection for gases like NH3, H2S, NO, and NO2, with ppb-level sensitivity and chemical robustness.
Implementation Method 1
The covalent-organic framework includes a plurality of metal-coordinated aromatic units that are linked to one another by aromatic linkers... the covalent-organic framework is in the form of a fully aromatic and conjugated structure... exhibit bulk conductivities up to 2.51×10−3 S/m
Implementation Method 2
Current chemiresistive sensors face several challenges, including limited conductivity, limited sensitivity, and limited stability... detecting a change in a property of the electrode and correlating the change in the property to the presence or absence of the analyte
Data Source
AI summary
In an embodiment, the present disclosure pertains to a method of sensing an analyte in a sample by: (1) exposing the sample to an electrode that includes a covalent-organic framework with a plurality of metal-coordinated aromatic units that are linked to one another by aromatic linkers; (2) detecting a change in a property of the electrode; and (3) correlating the change in the property to the presence or absence of the analyte. In an additional embodiment, the present disclosure pertains to said covalent-organic frameworks. Additional embodiments of the present disclosure pertain to methods of making the covalent-organic frameworks.