Defect-enabled room-temperature acetone gas sensors based on Zn-doped cauliflower-like bismuth oxide

Metal oxide-based gas sensors have promising advantages, such as low cost and high sensitivities, but the high working temperature (150°C-300°C) hinders their practical applications. Herein, this study demonstrated a Zinc (Zn)-doped approach to achieve defect-enabled room-temperature acetone gas sensors based on bismuth oxide (Bi₂O₃) thin film. Through a simple chemical bath deposition method, the varying substitutional doping of zinc (2 wt% to 8 wt%) can induce the morphological transformation of Bi₂O₃ nanosheets to a cauliflower-like nanostructure, leading to enhanced surface area and active sites. The incorporation of Zn ions can result in oxygen vacancies in the Bi₂O₃ lattice and the rising of the depletion layer, facilitating the interaction toward acetone molecules at ambient temperatures, leading to an increment of response ∼6. The Zn-doped cauliflower-like Bi₂O₃ electrode exhibits a superior sensing performance of acetone gas with a low detection limit of 1 ppm and high stability over 90 days. This work underscores the potential of controlled doping of Zn for oxygen vacancy-riched Bi₂O₃ thin film as a promising room-temperature acetone gas sensor, offering new avenues for the detection of hazardous gases with improved sensitivity.