Enhanced Acetone Sensing Performance of MgO/TiO ₂ Bilayer Thin Films Prepared by Sol–Gel Spin Coating

This study comparatively investigates the performance of TiO ₂ and MgO/TiO ₂ bilayer thin films produced by sol–gel spin coating in acetone‐detecting metal oxide gas sensors. XRD and FESEM analyses showed that the MgO substrate improved the crystallization of TiO ₂ films, increasing the crystallite size from 15 to 19 nm and the surface porosity from 49% to 57%. In measurements conducted under 50–200 ppm acetone, the MgO/TiO ₂ sensor exhibited approximately 56% higher performance compared to TiO ₂ , with a response value of 40.16 at 350 °C. Results indicate MgO/TiO ₂ films possess potential for breath analysis, environmental monitoring, and industrial safety.