Redox-Switchable Organic Compound Semiconductor Sensor for Chlorine Detection
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Solution Overview
Problem
Current methods for monitoring free chlorine concentration in drinking water are limited to laboratory settings due to the use of reagents, making continuous and autonomous monitoring challenging, especially in water distribution networks, where factors like temperature and sunlight affect chlorine levels.
Innovation Solution
A sensor using a redox-switchable organic compound to dope a semiconductor, changing its resistance in response to oxidants like chlorine and hydrogen peroxide, allowing for detection and quantification without reagents and enabling continuous monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If titration-based approaches with reagents are used to measure chlorine concentration, then measurement precision is improved, but device complexity and ease of operation worsen due to requirement of laboratory-based settings and frequent manual calibration
Solution Approach 1:
The sensor enables autonomous operation by using electrochemical methods that automatically generate sensory signals without requiring manual reagent addition or frequent calibration. The system self-regulates through electrochemical reactions between chlorine and the semiconductor material, providing continuous monitoring capability.
Solution Approach 2:
The patent replaces mechanical titration-based measurement systems with an electrochemical sensing system. Instead of manual titration procedures requiring laboratory equipment, the invention uses electrical signals to detect chlorine concentration through resistance changes in the semiconductor material.
2Measurement precision
If chemiluminescence methods with optical light sources and detectors are used, then measurement precision is improved, but device complexity and cost worsen
Solution Approach 1:
The patent substitutes optical detection systems with an electrochemical sensing system. Instead of using light sources and optical detectors, the invention measures chlorine concentration through electrical resistance changes in the semiconductor material, eliminating complex optical components.
Solution Approach 2:
The invention changes the detection parameter from optical signal intensity to electrical resistance. By measuring resistance changes in the semiconductor material caused by electrochemical reactions with chlorine, the system achieves simplified design while maintaining detection capability.
3Device complexity
If electrochemical methods are used for chlorine sensing, then device complexity is reduced and autonomous monitoring is enabled, but reliability worsens due to strong sensitivity to flow rate and electrode aging
Solution Approach 1:
The patent changes the electrode material from traditional electrochemical electrodes to a semiconductor material (such as carbon nanotubes). This parameter change reduces sensitivity to flow rate variations and electrode aging, improving reliability while maintaining the simplicity of electrochemical sensing.
Solution Approach 2:
The invention uses composite semiconductor materials, specifically carbon nanotube-based materials, to create a sensing element that combines electrical conductivity with chemical stability. This composite approach improves reliability by reducing degradation from aging and flow rate sensitivity while maintaining device simplicity.
4Measurement precision
If reagent-based methods are used for chlorine detection, then measurement precision is improved, but loss of substance worsens due to consumption of reagents
Solution Approach 1:
The sensor enables autonomous operation by using electrochemical methods that automatically generate sensory signals without requiring manual reagent addition or frequent calibration. The system self-regulates through electrochemical reactions between chlorine and the semiconductor material, providing continuous monitoring capability.
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 sensor provides a reliable, reagent-free method for monitoring free chlorine and hydrogen peroxide concentrations, with the ability to be electrochemically reset, suitable for continuous use in drinking water and water distribution networks.
Implementation Method 1
uses oxidation of a redox-switchable organic compound to dope a semiconductor to change its resistance
Implementation Method 2
The oxidation of the redox-switchable organic compound by the oxidant switches the doped semiconductor system into a low resistance (p-doped) state
Implementation Method 3
The p-doping of the doped semiconductor system can then be electrochemically reversed by polarizing it cathodically
Data Source
AI summary
The present application relates to sensors and methods for detecting and/or quantifying an oxidant such as free chlorine in a liquid sample such as drinking water. The sensors comprise a first electrode, a second electrode and a composite material between and connecting the first electrode and the second electrode, the composite material comprising a semiconductor and a redox-switchable organic compound associated therewith. The methods comprise exposing the liquid sample to the sensor under conditions to oxide the redox-switchable organic compound and analyzing a resulting change in current.