Surface engineering of gold-modified ZIF-8-derived ZnO thin films for enhanced acetone breath sensing

MOF-derived metal oxide thin films have attracted increasing attention due to their high surface area and tunable surface properties. Such modifications enhance gas adsorption, diffusion, and charge transfer for chemiresistive sensing. In this work, ZIF-8-derived ZnO thin films functionalized with Au nanoparticles were fabricated for high-performance acetone sensing relevant to breath-based lung cancer diagnosis. A compact ZnO thin film was first deposited by DC sputtering, followed by in situ ZIF-8 growth to increase surface area and porosity. Au was then deposited by DC sputtering, and thermal annealing at 600 °C converted ZIF-8 into porous ZnO and induced the formation of well-dispersed Au nanoparticles. The resulting [email protected] structure exhibited enhanced gas diffusion and active sites. It exhibits optimal operation at 350 °C and achieves a high response of 95% toward 10 ppm acetone, with fast response and recovery times of 17 s and 135 s, respectively. In addition, a low detection limit of 0.075 ppm is obtained. The sensor also shows excellent selectivity and stable sensing performance, with a response variation of about 5% over 90 days.