本研究利用紫外光聚合技術在氧化鋁基板上直接合成三氧化鎢/聚吡咯奈米複合材料，製備成室溫型硫化氫氣體感測元件。並利用掃描式電子顯微鏡(SEM)、X射線繞射儀(XRD)來分析三氧化鎢/聚吡咯奈米複合材料薄膜的結構和型態。
由SEM圖可知，聚吡咯覆蓋在三氧化鎢/聚吡咯奈米複合材料上。在室溫下，三氧化鎢/聚吡咯奈米複合材料感測硫化氫氣體的感度比純三氧化鎢或純聚吡咯高。同時三氧化鎢/聚吡咯奈米複合材料，在室溫下可偵測濃度極低的硫化氫氣體達100 ppb的硫化氫氣體。同時將利用三氧化鎢與聚吡咯所形成p-n型之非均勻結構(hetero-structure)的毀壞層(depletion layer)的電子結構模型來說明三氧化鎢/聚吡咯奈米複合材料薄膜在室溫下可偵測濃度極低的硫化氫氣體的感測機制。
A room-temperature H2S gas sensor was fabricated through in-situ photopolymerization of polypyrrole (PPy) and tungsten oxide (WO3) nanoparticles (PPy/WO3) nanocomposite thin film on an alumina substrate. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were used to analyze the structure and morphology of the fabricated films. Comparative gas sensing results indicated that the sensor that was based on the PPy/WO3 nanocomposite film exhibited a much higher sensitivity than that based on pure WO3 or PPy film in detecting H2S gas at room temperature. Microstructural observations revealed that PPy were covered the surface of PPy/WO3 nanocomposite film. Therefore, a model of potential barriers to electronic conduction in the composite material was used to suggest that the high sensitivity is associated with the stretching of the two depletion layers at the surface of the PPy film and at the interface of the PPy and the WO3 film when detected H2S gases are adsorbed at room temperature.
The sensor that is based on a nanocomposite film of PPy/WO3 exhibited a strong response in detecting very low concentrations of H2S gas at room temperature and is practical because of the ease of its fabrication.
