Effective detection of acetone gas molecules using PLD deposited tungsten oxide microwires for biomedical applications

Abstract

Skin gas sensors offer a non-invasive route for monitoring biomarkers such as acetone, relevant to metabolic conditions like diabetes. In this study, WO₃ thin films were deposited on LaAlO₃ (100) substrates via pulsed laser deposition and evaluated for acetone sensing. X-ray diffraction analysis confirmed the formation of highly crystalline WO₃ thin films at 600 °C. Atomic force microscopy analysis revealed a uniform film morphology with nanoscale grain structures, emphasizing the role of grain size in enhancing the gas adsorption and diffusion. The amorphous films exhibited an excellent response at 300 °C, detecting concentrations as low as 100 ppb in an air atmosphere. In addition, the fabricated sensor exhibited rapid response (19 s) and recovery (20 s) times. Distinct sensing mechanisms were observed under dry and ambient air conditions, indicating the influence of humidity and oxygen species. These findings demonstrate the significance of substrate selection, deposition parameters, and post-annealing treatment in tuning the structural and functional properties of WO₃-based thin film gas sensors for ultra-low detection of acetone gas molecules.