Miniaturized CO2 Sensor Using Interdigitated Electrodes and Thin-Film Electrolytes
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Solution Overview
Problem
Current bulk or thick film solid electrolyte carbon dioxide sensors are large, high in power consumption, difficult to batch fabricate, and costly, limiting their effectiveness in applications requiring sensitivity, selectivity, rapid response, and stability.
Innovation Solution
A miniaturized amperometric electrochemical CO2 sensor using semiconductor microfabrication techniques, with interdigitated electrodes and a novel arrangement of NASICON and auxiliary electrolytes (Na2CO3/BaCO3), allowing for robust operation and integration into small, low-power devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bulk or thick film solid electrolyte CO2 sensors are used, then sensitivity and selectivity are improved, but device size and power consumption increase
Solution Approach 1:
The sensor is divided into multiple functional layers (substrate, electrode layer, solid electrolyte layer, auxiliary electrolyte layer, protective layer) with each layer performing a specific function. This segmentation allows miniaturization while maintaining the electrochemical sensing mechanism that provides high sensitivity and selectivity for CO2 detection.
Solution Approach 2:
The patent transitions from bulk three-dimensional sensor structures to a planar thin-film configuration deposited on a substrate. This dimensional change enables miniaturization and batch fabrication while preserving the electrochemical reactions at the electrode-electrolyte interfaces that provide CO2 sensing capability.
2Measurement precision
If bulk or thick film solid electrolyte CO2 sensors are used, then sensitivity and selectivity are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The sensor structure is segmented into distinct functional layers that can be deposited sequentially using standard thin-film techniques. This layered architecture enables batch fabrication processes where multiple sensors can be manufactured simultaneously on a single substrate, reducing complexity and cost while maintaining the selective CO2 detection capability through the specific electrode-electrolyte interface design.
Solution Approach 2:
The patent changes the physical state and dimensions of the electrolyte materials from bulk/thick-film to thin-film configurations, and modifies the fabrication parameters to use standard semiconductor microfabrication techniques. This enables batch production with improved manufacturing ease while the electrochemical principles maintaining selectivity remain unchanged.
3Volume of moving object
If miniaturized sensors are fabricated using microfabrication techniques, then device size and power consumption are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The sensor is designed as a multi-layer structure where each layer has a defined function and can be deposited with standard thin-film thickness tolerances. This segmentation into robust functional layers (substrate, electrode, solid electrolyte, auxiliary electrolyte, protective layer) allows miniaturization to be achieved using conventional microfabrication techniques without requiring extreme manufacturing precision, as each layer compensates for variations in the others.
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, selectivity, and rapid response, with a compact, low-power design suitable for diverse applications including fire detection and environmental monitoring, while being easy to batch fabricate and cost-effective.
Implementation Method 1
an auxiliary electrolyte layer of sodium carbonate and barium carbonate (Na2CO3/BaCO3)
Implementation Method 2
amperometric electrochemical CO2 sensor
Implementation Method 3
The sensor is operated by applying voltage across the electrodes and measuring the resultant current flow
Data Source
AI summary
A gas sensor comprises a substrate layer; a pair of interdigitated metal electrodes, said electrodes include upper surfaces, the electrodes selected from the group consisting of Pt, Pd, Au, Ir, Ag, Ru, Rh, In, Os, and their alloys. A first layer of solid electrolyte staying in between electrode fingers and partially on said upper surfaces of said electrodes, said first layer selected from NASICON, LISICON, KSICON and β″-Alumina. A second layer of metal carbonate(s) as an auxiliary electrolyte engaging said upper surfaces of the electrodes and the first solid electrolyte. The metal carbonates selected from the group consisting of the following ions Na+, K+, Li+, Ag+, H+, Pb2+, Sr2+, Ba2+, and any combination thereof. An extra layer of metal oxide selected from the group consisting of SnO2, In2O3, TiO2, WO3, ZnO, Fe2O3, ITO, CdO, U3O8, Ta2O5, BaO, MoO2, MoO3, V2O5, Nb2O5, CuO, Cr2O3, La2O3, RuO3, RuO2, ReO2, ReO3, Ag2O, CoO, Cu2O, SnO, NiO, Pr2O3, BaO, PdO2, HfO3, HfO3 or other metal oxide and their mixtures residing above and in engagement with the second electrolyte to improve sensor performance and/or to reduce sensor heating power consumption.