Improvement in NO gas-sensing properties using heterojunctions between polyaniline and nitrogen on activated carbon fibers

The effect of heterojunctions between polyaniline (PANi) and nitrogen-containing carbon fibers (NCFs) on NO gas-sensing properties were investigated, and the influence of the heterojunction area on the NO gas-sensing performance was confirmed. We prepared NCFs and nitrogen-containing activated carbon fibers (NACFs) from polyacrylonitrile fibers and then loaded them with PANi so they could be used as gas-sensing materials. In the NO gas-sensing tests, the NCFs and pristine PANi exhibited p-type behavior with decreased responses over time, and the PANi-loaded NCFs (PANi/NCFs) exhibited different behavior with a very high response (281.0%). This high response can be attributed to the formation of p-p heterojunctions at the interfaces between the PANi and NCFs caused by the graphitic nitrogen in the NCFs. Moreover, the response of the PANi-loaded NACFs (PANi/NACFs) was 2.2 times that of the PANT/NCFs, which is due to the activation of NCFs increasing the p-p heterojunction area of the PANi/NACFs. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.