Study On Gas Sensitivity Of Lithium Iron Phosphate Nonoparticles And Polymer Film

Air pollution has become an inescapable reality in the world’s urban population lives. With the rapid development of industry, types and quantities of atmospheric pollutants is increasing. Various air pollutants enter the body through a variety of ways. The impact on the human body is a multifaceted and the harm is extremely serious. So people urgently need to constantly research and develop the method to detect environmental pollutants.The optical waveguide(OWG) chemical sensors has mechanical strength, high sensitivity, system compactness, fast response, anti-electromagnetic interference, easy to operate at room temperature, easy realization for on-line continuous monitoring and many other features, has important research prospects in the area of applied chemistry, industrial production and biological monitoring and detection of harmful gases. As an important part of the OWG, sensitive materials will directly affect the performance of the sensor, such as stability, selectivity, sensitivity and response time. Therefore, the selection of appropriate sensitive materials is important. Nano-material is the most dynamic area of new materials and has a very important influence in the future social and economic development, it is also the most active part of the nano-technology. In this paper, combine with unique properties of nano-materials and superiority of OWG.The first chapter is part of introduction. In this part, the Nano science and technology development, the sensor technology, the optical chemical sensors and its classification were introduced. Types of sensitive materials and the characteristics of several sensitive materials used in this paper were mainly introduced.The second chapter, mainly describe the theory of OWG. In this part, formation condition of the guide light(total internal reflection of light), the structure of planar OWG, guide of plannar waveguide mode. At last, the topic sources and contents of this study work were put forward.The third chapter is mainly about the gas sensitivity study of LiFePO4-SDBS composite thin film/tin-diffused glass optical waveguide sensor. In this part the best ultrasound time, ultrasound temperature and the concentration of dispersant were selected. LiFePO4-SDBS composite thin film/tin-diffused glass optical waveguide sensor. The resistance change of WS-30 A gas testing system was consistence with the change of output light intensity in OWG gas testing system. The results showed that, the sensors can detect 1×10-7(volume ratio) of Styrene.The forth chapter is mainly about the gas sensitivity study of LiFePO4-PVA composite thin film/tin-diffused glass optical waveguide sensor. In this study, the PVA doped LiFePO4 sol was synthesized by a sol-gel method and the sensor was fabricated by coating a tin-doped glass optical waveguide with a LiFePO4-PVA composite film. In this part the best ultrasound time, ultrasound temperature and the concentration of dispersant were selected. LiFePO4-SDBS composite thin film/tin-diffused glass optical waveguide. The results showed that, the sensors can detect 1×10-6(volume ratio) of Xylene.The fifth chapter is the concluding part, the main content of our research study was summarized.