Regulation of N-type In2O3 Content on the Conductivity Type of Co3O4 Based Acetone Sensor

Abstract

Abstract A double-jet electrospinning method was adopted to fabricate In 2 O 3 /Co 3 O 4 nanofibers (NFs). The sensitivity of In 2 O 3 /Co 3 O 4 NFs and In 2 O 3 NFs were compared and analyzed, and the morphology, structure, chemical composition, and gas-sensing properties of the samples were comprehensively characterized. The results show that the introduction of Co 3 O 4 can improve the response of In 2 O 3 /Co 3 O 4 to acetone, to 29.52 (In 2 O 3 /Co 3 O 4 ) and 12.34 (In 2 O 3 ) to 200 ppm acetone at 2000°C, respectively. In addition, the doping of Co 3 O 4 was found to reduce the optimum working temperature of pure In 2 O 3 from 275°C to 200°C. The composite of Co 3 O 4 and In 2 O 3 not only enhances the sensing performance, but also leads to a conversion of p-n conductivity type. The phenomenon of the p-n transition is relevant to operating temperature and proportion of In 2 O 3 and Co 3 O 4 . While the enhanced acetone sensing properties of In 2 O 3 /Co 3 O 4 NFs may be attributed to the p-n heterojunction between n-type In 2 O 3 and p-type Co 3 O 4 crystalline grains, which promotes the electron migration. The synergistic effects between In 2 O 3 and Co 3 O 4 and the large specific surface area of NFs additionally contribute to the improvements of acetone sensing performance.