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.