on the body for a long time, the genetic material will be damaged and mutations occur, which will result in abnormalities in the offspring. [4] Thus, it is urgent to develop devices to monitor these toxic gases. [5] The current devices for analyzing gas state pollutants are thin-layer chromatography scanner, [6] flame ionization detector, [7] gas chromatography-mass spectrometer (GC-MS), [8] and high-performance liquid chromatograph. [9] They can accurately detect and analyze these harmful gases, but they are bulky, expensive, laborious, and time-consuming. In addition, they cannot achieve real-time detection, so they cannot be widely used. By contrast, gas sensors have the advantages of portability, low expense, real-time monitoring and high sensitivity. According to different sensing principles, gas sensors can be divided into resistance-based, [10] optical, [11] micro-cantilever, [12] surface plasmon resonance, [13] surface acoustic, [14] and microwave sensors. [15] Among them, the resistance-based gas sensors have become a research hotspot due to their high sensitivity, good repeatability, and excellent selectivity. [16] Based on our survey, the history of resistance-based gas sensors dates back to several decades ago. Approximately 60 years ago, Brattain and Heiland discovered that the resistances of semiconductor materials vary according to the atmosphere. [17] Soon, Seiyama et al. applied this feature to detect harmful gases. [18] Then the first resistancebased gas sensor was successfully designed and patented by Taguchi. [17] The boiling point of triethylamine (TEA) is 89.5 °C at the normal temperature and pressure. Since its molecular formula contains hydrogen and carbon atoms, it is classified as a volatile organic compound (VOC). [19] Hitherto, TEA has been widely applied in many areas, such as, agriculture, fishery, and aviation, as well as, medication and health. [20] For example, it can be used as preservatives, surfactants, organic solvents, catalysts, etc. Moreover, studies have shown that putrid fish and shellfish releases TEA. In this regard, TEA can be used as a criterion to access the freshness of marine fish. [21] However, TEA harms the human body, mainly as a strong irritation to the skin and mucous membranes as well as the central nervous system. After prolonged exposure to TEA, some people are infected with emphysema and even die directly. According to the recommendations of the National Institute for Occupational Safety and Health Administration (NIOSH), the concentration of indoor TEA should be lower than 10 ppm. [22] The structure, application and hazards of TEA are schematic illustrated in Figure 1.Resistance-based gas sensors are effective in monitoring TEA. Currently, these resistance-based sensors are mainly With the demanding detection of unique toxic gas, semiconductor gas sensors have attracted tremendous attention due to their intriguing features, such as, high sensitivity, online detection, portability, ease of use, and low cost. Triethylamine, a typical gas of volatile organic...
