The characteristics and future trends of gas sensors
Gas sensors are a major category of chemical sensors. From working principles, characteristic analysis to measurement technology, from materials used to manufacturing processes, from detection objects to application fields, independent classification standards can be formed, resulting in various complex classification systems. Especially in the issue of classification standards, there is currently no unified system, making it difficult to strictly classify them.
Stability refers to the stability of the sensor's basic response throughout the entire working time, which depends on zero drift and interval drift. Zero drift refers to the change in sensor output response during the entire working time when there is no target gas present. Interval drift refers to the change in output response of a sensor continuously placed in the target gas, manifested as a decrease in the sensor output signal during working time. Ideally, a sensor would have a zero drift of less than 10% per year under continuous operating conditions.
Sensitivity refers to the ratio of the change in sensor output to the change in measured input, which mainly depends on the technology used in the sensor structure. The design principles of most gas sensors use biochemistry, electrochemistry, physics, and optics. The first consideration is to choose a sensitive technology that has sufficient sensitivity to detecting the percentage of TLV threshold or LEL lower explosive limit of the target gas.
Selectivity is also known as cross sensitivity. It can be determined by measuring the sensor response generated by interfering gases of a certain concentration. This response is equivalent to the sensor response generated by a certain concentration of target gas. This characteristic is crucial in tracking multiple gases, as cross sensitivity reduces measurement repeatability and reliability. Ideal sensors should have high sensitivity and selectivity.
Corrosion resistance refers to the ability of a sensor to be exposed to high volume fraction target gases. When there is a large amount of gas leakage, the probe should be able to withstand 10-20 times the expected gas volume fraction. Under normal operating conditions, sensor drift and zero correction values should be minimized as much as possible. The basic characteristics of gas sensors, such as sensitivity, selectivity, and stability, are mainly determined by the selection of materials. Select appropriate materials and develop new materials to achieve optimal sensitivity characteristics of gas sensors.
1、Emphasis on research and development of new gas sensitive materials and manufacturing processes
Research on gas sensor materials has shown that metal oxide semiconductor materials such as ZnO, SiO2, Fe2O3 have become more mature, especially in gas detection such as C ratio, C2H5OH, and CO. There are two main directions for this work:
One is to use chemical modification methods to dope, modify, and surface modify existing gas sensitive membrane materials, and improve and optimize the film-forming process to enhance the stability and selectivity of gas sensors; The second is to develop new gas sensitive membrane materials, such as composite and hybrid semiconductor gas sensitive materials and polymer gas sensitive materials, so that these new materials have high sensitivity, selectivity, and stability to different gases. Due to the advantages of abundant materials, low cost, simple film making process, easy compatibility with other technologies, and working at room temperature, organic polymer sensitive materials have become a research hotspot.
2、Development of a new type of gas sensor
Using traditional working principles and certain new effects, priority is given to the use of crystal materials (silicon, quartz, ceramics, etc.), advanced processing technology and microstructure design are adopted to develop new sensors and sensor systems, such as the development and use of optical waveguide gas sensors, polymer surface acoustic waves, and quartz harmonic gas sensors, as well as research on microbial gas sensors and biomimetic gas sensors. With the application of new materials, processes, and technologies, the performance of gas sensors is becoming more perfect, making the miniaturization, miniaturization, and multifunctionality of sensors have advantages such as good long-term stability, convenient use, and low price.
3、Intelligent gas sensor
With the continuous improvement of people's living standards and the increasing emphasis on environmental protection, higher requirements have been put forward for gas sensors in detecting various toxic and harmful gases, monitoring air pollution, industrial waste gas, and detecting food and residential environment quality. The successful application of new material development technologies such as nanomaterials and thin film technology provides a good prerequisite for the integration and intelligence of gas sensors.
Gas sensors will be developed on the basis of fully utilizing multidisciplinary comprehensive technologies such as micro machinery and microelectronics, computer technology, signal processing technology, sensing technology, fault diagnosis technology, intelligent technology, etc. Developing fully automatic digital intelligent gas sensors that can simultaneously monitor multiple gases will be an important research direction in this field.
Qingdao Xinnovis Microsystem Technology Co., Ltd.
Qingdao Xinnovis Microsystem Technology Co., Ltd. is a high-tech enterprise specializing in industrial intelligent sensor chip design, module development, and high-end metering instrument R&D, manufacturing and sales. The company is located in Qingdao International Innovation Park, Laoshan District, Qingdao, adjacent to Shandong University (Qingdao Campus), Ocean University of China, Beihang Institute of Microelectronics, Lanhua Institute of Chinese Academy of Sciences (Qingdao), Qingdao University and other famous universities.
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