Room-Temperature Gas Sensor Layer Structure
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Solution Overview
Problem
Existing gas sensors are costly, complex to manufacture, and often require high working temperatures, leading to limited accuracy, cross-sensitivity to other gases, and safety concerns, especially when measuring hydrogen, which hinders their use in portable and cost-effective applications.
Innovation Solution
A sensor with a layer arrangement comprising a metal base layer, a porous metal oxide middle layer, and a conductive carbon or organic top layer, allowing for conductivity or resistance measurements at ambient temperatures, reducing the need for noble metals and enabling selective detection of gases like hydrogen and humidity without heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional gas sensors are used, then measurement capability is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The sensor is divided into three functional layers: a base layer (metal or metal oxide), a middle layer (metal oxide for gas interaction), and a top layer (conductive material for signal detection). This segmentation allows each layer to perform its specific function independently, simplifying the overall manufacturing process while maintaining measurement capability
Solution Approach 2:
The invention changes the operational temperature parameter from high temperature (conventional sensors requiring heating elements) to room temperature operation. This parameter change eliminates the need for complex heating infrastructure, reducing manufacturing complexity and device cost while preserving gas detection functionality through the metal oxide layer's temperature-independent sensing mechanism
2Reliability
If high working temperature is used, then sensor performance is improved, but safety risks and energy consumption increase
Solution Approach 1:
The operating temperature parameter is changed from high temperature (e.g., 300-500°C) to room temperature operation. This eliminates safety risks associated with high temperature operation, particularly when measuring explosive gases like hydrogen, while the metal oxide layer maintains its gas-sensing properties at lower temperatures
Solution Approach 2:
The invention eliminates the need for heating elements and associated high-temperature infrastructure, converting the potential harm of high-temperature operation into a benefit of safe, room-temperature operation. The metal oxide layer's inherent properties enable this temperature reduction without sacrificing sensing performance
3Temperature
If heating elements are added, then sensor operation is enabled, but device complexity and cost increase
Solution Approach 1:
The heating element, a complex and costly component in conventional sensors, is completely extracted and removed from the device architecture. The metal oxide layer is designed to function at room temperature, eliminating the need for any heating infrastructure and significantly simplifying the device
Solution Approach 2:
The metal oxide layer inherently performs the gas-sensing function at room temperature without requiring external heating assistance. The material's properties enable it to operate autonomously at ambient conditions, eliminating the need for auxiliary heating systems
4Measurement precision
If noble metals are used, then sensor sensitivity is improved, but manufacturing cost increases
Solution Approach 1:
The invention replaces expensive noble metals (platinum, gold) with inexpensive base metals (copper, aluminum, zinc) or conductive carbon materials in the top layer. The metal oxide middle layer provides the sensing function without requiring noble metals, enabling cost-effective manufacturing while maintaining adequate sensitivity for practical applications
Solution Approach 2:
The sensor uses a composite structure combining metal oxide (for gas interaction) with base metals or conductive carbon materials (for electrical signal). This composite approach replaces noble metals with cheaper material combinations that achieve the necessary sensing performance at lower cost
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 achieves high sensitivity and selectivity for various gases and liquids at room temperature, reducing production and operational costs, enhancing measurement accuracy, and enabling safe, portable, and cost-effective applications.
Implementation Method 1
the top layer being porous and having a material which is selected from the group consisting of electrically conductive carbon compounds, such as in particular graphite or carbon nanotubes (CNT), organic electrical conductors and base metals
Implementation Method 2
the base layer and the top layer can be electrically contacted for a conductivity measurement and/or a resistance measurement
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The present invention relates to a sensor (10) with a layer structure (12), wherein the layer structure (12) has at least one base layer (14), a middle layer (16) and a cover layer (18), the middle layer (16) being at least partially arranged on the base layer (14) and being in contact therewith, and the cover layer (18) being arranged at least partially on the middle layer (16) and being in contact therewith. The base layer (14) contains a metal, the middle layer (16) contains a metal oxide, and the cover layer (18) is porous and contains a material selected from the group consisting of electrically conductive carbon compounds, in particular graphite or carbon nanotubes (CNTs), organic electrical conductors and base metals. The base layer (14) and the cover layer (18) can be electrically contacted for a conductivity measurement and/or a resistance measurement. Said sensor (10) provides a high sensitivity at a high selectivity already at ambient temperature and is also particularly economical to manufacture. The present invention further relates to a method for manufacturing a sensor (10). The present invention also relates to the use of the sensor (10) according to the invention as a gas sensor and/or liquid sensor.