Elevated room temperature functionality of ethanol gas sensors based on zirconium doped zinc oxide nanostructures

Abstract This study explores the efficacy of zirconium (Zr)-doped zinc oxide (ZnO) nanostructures in ethanol gas sensing, emphasizing the influence of varying Zr doping concentrations on the enhancement of sensor functionality, especially at room temperature and ambient conditions. Both undoped and Zr-incorporated ZnO nanoparticles were synthesized using a sol–gel approach, with Zr concentrations adjusted to 0, 1, 2, and 3 mol%. Thin films were subsequently deposited onto soda-lime glass substrates via a dip-coating method. X-ray diffraction confirmed the hexagonal wurtzite structure with a predominant (002) orientation. Scanning electron microscopy revealed uniformly distributed nanoscale grains and pores, while energy-dispersive x-ray spectroscopy verified the elemental composition and stoichiometric ratios of zinc, zirconium, and oxygen. The ethanol sensing properties were assessed by measuring electrical resistance changes upon exposure to ethanol concentrations (10–100 ppm) at room temperature. The incorporation of Zr was found to significantly enhance the sensing functionality of ZnO, with the optimal Zr concentration determined to be 1 mol%. The sensor incorporating 1 mol% Zr (ZrZO1) demonstrated exceptional ethanol gas sensing capabilities, achieving a sensing response of 32, along with rapid response and recovery times of 18 s and 23 s, respectively. The ZrZO1 sensor exhibited superior functionality metrics, including high sensitivity, excellent reproducibility, long-term stability, and rapid response/recovery characteristics, making it a promising candidate for the development of advanced gas sensors operating at room temperature. These findings highlight the potential of Zr-incorporated ZnO nanostructured thin films as a highly effective material for ethanol gas sensing applications under ambient conditions.