Ammonia Sensing Performance of an Al-Doped SnO₂ Thin Film Decorated With Platinum Nanoparticles

A new ammonia (NH3) sensor based on the incorporation of an Al-doped SnO2 (ATO) thin layer and platinum (Pt) nanoparticles (NPs) is produced. The employed Pt NPs effectively enhance the ammonia sensing behaviors due to enlarged specific surface area and advanced catalytic ability of noble Pt metal. Compositional, elemental, and morphological analyses are made to check the designed structure. In the experiment, good ammonia detecting performance including an advanced sensing response of 817.2 with a small response (recovery) time of 35 s (7 s) under 1000 ppm NH3 gas and an extremely lower detectable level of 20 ppb NH3 are obtained at 275°C. Moreover, the presented sensor demonstrates prominent long-term (120 d) stability toward ammonia gas.