Chemoresistor Gas Sensor Pulsed UV Sensitivity
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Solution Overview
Problem
Current micro-sensors, particularly semi-conducting metal-oxide gas sensors, face challenges in achieving high sensitivity and selectivity for gas detection and composition analysis, requiring improved accuracy and faster measurement times while minimizing material damage.
Innovation Solution
A multi-storey gas sensor architecture is introduced, where a semi-conducting metal-oxide or conducting polymer sensing element is exposed to a selectively-activatable layer that changes the gas composition, allowing for varied measurements by altering operating conditions such as temperature and UV exposure, and using pulsed UV radiation to enhance sensitivity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing layer is heated to high temperature for useful adsorption phenomena, then gas detection sensitivity is improved, but material damage and energy consumption increase
Solution Approach 1:
The patent applies periodic heating cycles where the sensing layer is heated to high temperature only during measurement phases to enable useful adsorption phenomena, then cooled during non-measurement phases to prevent material damage. This periodic action allows the system to achieve high detection sensitivity when needed while minimizing cumulative thermal stress and energy consumption.
2Productivity
If the sensing layer is heated to high temperature for rapid cleaning, then measurement speed is improved, but material damage increases
Solution Approach 1:
The patent implements periodic heating cycles where rapid high-temperature heating is applied only during brief cleaning intervals between measurements. This allows rapid desorption of adsorbed particles for quick sensor regeneration, while the limited duration and controlled frequency of these heating episodes prevent excessive material damage.
Solution Approach 2:
The patent uses brief, intense heating pulses that rapidly pass through the sensing layer to achieve quick cleaning without prolonged exposure to damaging temperatures. The heating occurs in short bursts just long enough to desorb particles, then immediately stops, minimizing material damage while maintaining fast measurement turnover.
3Device complexity
If a single sensing element is used, then device complexity is reduced, but measurement accuracy and selectivity decrease
Solution Approach 1:
The patent divides the sensing system into multiple independent sensing elements, each potentially with different sensing layer compositions or properties. This segmentation allows each element to respond differently to various gas components, providing multiple measurement signals that can be processed to improve overall detection accuracy and selectivity while maintaining relatively simple individual element structures.
Solution Approach 2:
The patent designs multiple sensing elements that can be used for different detection purposes or combined to provide comprehensive gas analysis. Each element serves as a universal building block that can detect different gases or gas components, allowing the system to achieve high measurement precision and selectivity through coordinated operation of multiple elements rather than requiring complex single-element designs.
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 multi-storey architecture increases the number of data points generated, improving the accuracy and speed of gas detection and composition analysis, while minimizing material damage and optimizing sensor performance.
Implementation Method 1
it is necessary to heat the sensing layer 2 to a relatively high temperature (notably 250° C. or above depending on the material forming the sensing layer and the gas species to be detected) for useful adsorption phenomena to be observed
Implementation Method 2
gas particles G may become adsorbed on the surface of the sensing layer 2
Implementation Method 3
the heater 6 is activated to heat the active layer to a high temperature, above the usual operating temperature, so as to cause de-sorption of adsorbed particles
Implementation Method 4
plural sources of ultraviolet light operable to expose selected gas-sensing layers of the array to ultraviolet light
Implementation Method 5
pulsed UV radiation to enhance sensitivity and selectivity
Data Source
AI summary
The sensitivity and/or selectivity of a chemoresistor type gas sensor is enhanced by measuring the response of the sensing material to a gas sample while the sensing material is subjected to illumination using specially-tailored pulses of ultraviolet radiation. For a given target gas to be detected there is an optimal duration of the UV pulses to achieve peak sensitivity of the sensing material.