• Bonciu, Anca-Florina
• Dobrescu, Stefan
• Marascu, Valentina
• Bercea, Adrian Ionut
• Alexandra, Papavlu P.
• Filipescu, Mihaela
• Brajnicov, Simona

Abstract

<jats:p>A highly sensitive ammonia-gas sensor based on a tungsten trioxide and polypyrrole (WO3/PPy) nanocomposite synthesized using pulsed-laser deposition (PLD) and matrix-assisted pulsed-laser evaporation (MAPLE) is presented in this study. The WO3/PPy nanocomposite is prepared through a layer-by-layer alternate deposition of the PPy thin layer on the WO3 mesoporous layer. Extensive characterization using X-ray diffraction, FTIR and Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and water contact angle are carried out on the as-prepared layers. The gas-sensing properties of the WO3/PPy nanocomposite layers are systematically investigated upon exposure to ammonia gas. The results demonstrate that the WO3/PPy nanocomposite sensor exhibits a lower detection limit, higher response, faster response/recovery time, and exceptional repeatability compared to the pure PPy and WO3 counterparts. The significant improvement in gas-sensing properties observed in the WO3/PPy nanocomposite layer can be attributed to the distinctive interactions occurring at the p–n heterojunction established between the n-type WO3 and p-type PPy. Additionally, the enhanced surface area of the WO3/PPy nanocomposite, achieved through the PLD and MAPLE synthesis techniques, contributes to its exceptional gas-sensing performance.</jats:p>

Topics

• Deposition
• nanocomposite
• impedance spectroscopy
• surface
• scanning electron microscopy
• x-ray diffraction
• atomic force microscopy
• tungsten
• Raman spectroscopy
• evaporation