Electrical and gas sensing properties of polyaniline functionalized single-walled carbon nanotubes

摘要

Electrical and gas sensing properties of single-walled carbon nanotube networks functionalized with polyaniline (PANI-SWNTs) were systematically investigated to understand the gas sensing mechanisms and optimize sensing performance. The temperature-dependent electrical resistance and field-effect transistor (FET) transfer characteristics indicated that the electrical properties of PANI-SWNTs are dominated by the PANI coating. The FET transfer characteristics of PANI-SWNTs exposed to different NH3 concentrations indicated that the dominant sensing mechanism is the deprotonation of PANI by NH3. Sensing experiments with different gas analytes revealed that PANI-SWNTs responded positively to NH3, and negatively to NO2 and H2S with sensitivities of 5.8% per ppm(v) of NH3, 1.9% per ppm(v) of NO2, and 3.6% per ppm(v) of H2S. The lower detection limits were 50, 500, and 500 ppb for NH3, NO2, and H2S, respectively.