Ozone (O₃), also known as superoxide, is an allotrope of oxygen (O₂), a blue gas with special smellly at room temperature. Ozone has the smell of grass, and the excessive inhalation will cause certain hazards to human health. Because ozone has a very strong oxidation, it plays an excellent role in sterilization, such as household ozone disinfection cabinet, air deodorization and sterilization etc.. However, ozone is also toxic and corrosive because of its strong oxidation, which will irritate and damage the eyes, respiratory system and other mucosal tissue.

 

In recent years, with the air pollution has been growing concerned, ozone pollution is also gradually known to us. Ozone pollution has great confusing, because it tends to occur in those days when the sky is clear and sunny, and people exposure to them without realizing they are being damaged, and even thinking about how good the air quality is. China has made provisions about the upper limit of the ozone concentration which in particular:  Grade 1 of 120μg/m³; grade two of 160μg/m³; grade three of 200μg/m³; and when the concentration of ozone in the air exceeds 205μg/m³, it will cause a serious harm to human body. In addition, ozone pollution can also cause plant leaf necrosis, long bleached spots, growth was inhibited, resulting in crop production; also, ozone will result in material fade, photo matting and tire aging, causing economic losses. Thus, in certain circumstances, the detection of ozone content it is very necessary, and its particularly important to study the ozone gas sensor.

 

Study found that WO₃ has a good property of gas sensing to ozone, Cantalini ect. prepared WO₃ films gas sensor by the sol-gel method, vacuum thermal evaporation and sputter deposition technology, and the experiments found that the thin film can detect the concentration of 21.4~342.4μg/m³ of ozone at the operating temperature of 200~400°C, and has a good signal reproduction. Bendahan etc. prepared WO₃ films at different oxygen content (18% to 65%) of the environment by reactive magnetron sputtering technique, and found this kind of gas sensor has a good response to ozone under 150°C, and moreover, compared with other ozone sensors, it has a shorter response - recovery time.