Acetone sensing mechanism of Ar/O2 plasma modified indium oxide electrospun fibers: A combined DFT and experimental study

Surface adsorbed oxygen plays a crucial role in the redox reactions of semiconductor gas sensors. A novel, radio frequency plasma modification method, using mixed Ar/O2, was applied to surface treatment of In2O3 electrospun nanofibers to form an oxide-rich structure. Acetone adsorption behavior on the In2O3 (110) surface was investigated using density functional theory (DFT). With the injection of high-energy Ar/O2 plasma, an unoccupied electronic state was formed in the valence band electronic structure of In2O3. The adsorption energy of acetone on In2O3 after modification was 0.136 eV higher than before plasma modification. The adsorption ability of acetone was greatly improved after modification of Ar/O2 plasma. In2O3 sensors were fabricated before and after plasma modification, and the acetone sensing performances were measured. Gas sensing measurement showed that the Ar/O2 mixed plasma modification caused a unique improvement in the acetone sensing performance of the In2O3 sensors.