Carbon Wire Gas Sensor with Metal Oxide Nanowires
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Solution Overview
Problem
Existing gas sensors, particularly semiconductor-type sensors, face limitations in sensitivity due to unstable physical and electrical connections between nanomaterials and electrodes, high manufacturing costs, and difficulties in mass production, especially when detecting gases like carbon dioxide and nitrogen oxide.
Innovation Solution
A gas sensor is developed with carbon wires and metal oxide nanowires integrated to enhance electrical conductivity, where the carbon wire is spaced apart from the substrate to minimize substrate interference, and metal oxide nanowires are grown radially on the carbon wire for improved sensitivity and accessibility, allowing for controlled resistance changes and easy mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If nanomaterials are non-uniformly dispersed on electrode surface to measure electrical resistance, then sensitivity is improved, but physical and electrical connection stability between nanomaterials and electrodes deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-patterning electrodes with specific geometries (interdigitated, comb, or mesh structures) before nanomaterial deposition. This pre-configuration ensures that nanomaterials form continuous networks between electrodes, establishing stable physical and electrical connections in advance while maintaining high sensitivity for gas detection.
2Ease of manufacture
If semiconductor thin film is used as sensing material, then manufacturing is simplified, but sensitivity is limited and cannot detect stable chemical materials like CO2
Solution Approach 1:
The patent employs composite materials by combining metal oxide nanomaterials (such as ZnO, SnO2, or TiO2) with semiconductor thin films or using nanomaterial networks on electrode substrates. This composite structure maintains manufacturing simplicity while achieving high sensitivity for detecting stable chemical materials like CO2, overcoming the limitations of pure semiconductor thin films.
3Measurement precision
If electrochemical method is used with electrolyte solution, then gas sensing capability is achieved, but reaction rate is extremely low and cost is high
Solution Approach 1:
The patent replaces the electrochemical method with a physical resistance measurement method. Instead of using electrolyte solutions and electrochemical reactions, the patent measures electrical resistance changes of nanomaterial networks directly, eliminating the need for slow chemical reactions and expensive electrolyte systems while maintaining gas sensing capability.
4Measurement precision
If optical method by infrared absorption is used, then interference from mixed gases and humidity is reduced, but device becomes complicated and size increases
Solution Approach 1:
The patent substitutes the complex optical infrared absorption system with a simple electrical resistance measurement system. By measuring resistance changes of nanomaterial networks exposed to gases, the patent achieves selectivity without requiring complicated optical components, large device size, or expensive infrared sources and detectors.
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 solution achieves stable physical and electrical contact between carbon wires and electrodes, increases sensitivity by minimizing substrate effects, and enables cost-effective, high-productivity mass production of gas sensors with enhanced performance.
Implementation Method 1
a gas sensor which measures change in electrical resistance of a nanoparticle itself or a material coating the nanoparticle according to concentration of a gas to be measured
Implementation Method 2
a gas sensor using carbon nanotube as one of the semiconductor-type gas sensor has an advantage in that sensitivity thereof is thousands of times higher than those of other sensors since the carbon nanotube is possible to be operated even at room temperature, and has nano-sized particles
Implementation Method 3
forming a carbon wire and a pair of carbon electrodes that are connected to be integrated with each other, by pyrolyzing the photoresist wire and the pair of photoresist electrodes
Data Source
AI summary
Provided is a method for manufacturing a gas sensor according to an exemplary embodiment of the present invention including: a) forming a pair of photoresist electrodes spaced apart from each other and a photoresist wire connecting upper portions of the pair of photoresist electrodes to each other by exposing and developing a first photoresist coated on a substrate; b) forming a pair of carbon electrodes and a carbon wire that are connected to be integrated with each other, by pyrolyzing the pair of photoresist electrodes and the photoresist wire; and c) forming metal oxide nanowires on a surface of the carbon wire.