TMDC Nanopore Formation Using Ionic Current Feedback
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Solution Overview
Problem
Current methods for forming nanopores in ultrathin membranes, particularly for molecular sensing, are costly, time-consuming, and lack scalability and precision, making them unsuitable for mass production and reliable use in bio-sensing applications, especially for 2D materials like MoS2 where sub-nanometer precision is required.
Innovation Solution
A method involving the application of a transmembrane voltage to a transition metal dichalcogenide (TMDC) thin layer immersed in an electrically conducting liquid, monitoring the ionic current to achieve precise control over nanopore formation, allowing for in-situ fabrication with sub-nanometer precision and adaptability to different biomolecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If TEM (Transmission Electron Microscope) is used to form nanopores, then nanopore formation is achieved, but the process becomes expensive, time-consuming, and not scalable
Solution Approach 1:
The patent replaces the mechanical/physical TEM drilling process with a chemical electrochemical etching process. Instead of using electron beams and complex vacuum equipment, the invention uses electrochemical reactions in liquid electrolyte to remove material and form nanopores, thereby achieving the same function through a fundamentally different mechanism that is more scalable and cost-effective
Solution Approach 2:
The patent introduces liquid electrolyte as an intermediary medium to enable nanopore formation. The electrolyte serves as the medium through which electrochemical reactions occur, allowing material removal and pore formation without requiring vacuum conditions or complex instrumentation like TEM, thus simplifying the process and enabling scalability
2Productivity
If high voltage pulses are applied to form nanopores via dielectric breakdown, then nanopore formation is achieved, but the process becomes uncontrollable and quality varies
Solution Approach 1:
The patent implements feedback control by monitoring the ionic current through the membrane during the electrochemical etching process. As the nanopore forms and its diameter changes, the ionic current changes accordingly. This real-time monitoring allows the system to detect when the desired pore size is achieved and adjust or stop the etching process, thereby maintaining precise control over nanopore dimensions while enabling continuous production
Solution Approach 2:
The patent employs dynamic control of the electrochemical etching process by adjusting parameters such as applied voltage, current density, and etching time based on real-time feedback from ionic current measurements. This dynamic adjustment allows the process to adapt during nanopore formation, ensuring precise diameter control while maintaining high productivity through optimized etching rates
3Measurement precision
If sub-nanometer precision nanopores are formed in 2D materials like MoS2, then sensing precision is improved, but the fabrication process becomes more difficult and less scalable
Solution Approach 1:
The patent achieves sub-nanometer precision nanopore fabrication in 2D materials by precisely controlling electrochemical parameters such as applied voltage, current density, electrolyte composition, and etching time. By optimizing these parameters, the process achieves atomic-level precision in pore size control while maintaining simplicity and scalability, as the electrochemical etching can be performed using standard laboratory equipment rather than complex facilities
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
This method enables the accurate, controllable, and reproducible formation of nanopores with sub-nanometer precision, facilitating mass production and efficient bio-sensing, particularly for 2D materials like MoS2, by monitoring ionic current and adjusting pore size on demand, thus enhancing the precision and scalability of nanopore fabrication.
Implementation Method 1
applying a transmembrane voltage (V) at a value higher than the oxidation potential of the transition metal of the said TMDC to the said TMDC thin layer
Implementation Method 2
measuring the ionic current (Ii) in the said electrically conducting liquid
Data Source
AI summary
The invention relates to a method for making nanopores in thin layers or monolayers of transition metal dichalcogenides that enables accurate and controllable formation of pore within those thin layer(s) with sub-nanometer precision.