Tuning the Sensitivity and Temperature Stability of NO_2 Gas Sensors based on Networked Single-wall Carbon Nanotubes: A Surface Density Effect

摘要

Our objective in this paper is to minimize the temperature interference, an inherent problem to environmental gas sensing, with the NO_2 gas sensitivity of gas sensors based on SWNT (single-wall carbon nanotube) networks. We systematically change the surface density of the networked SWNTs and compare the NO_2 sensitivities at various sensing temperatures (30 to 75 ℃). The results show that the NO_2 gas sensitivity and its temperature stability are highly dependent on the surface density of the networks. Lower surface density leads to higher NO_2 sensitivity, which is consistent with previous studies. However, SWNT networks with higher surface density are more stable against the temperature changes. Based on these findings, we propose to optimize the surface density of the networks to suppress the temperature interference while maintaining high detection sensitivity sufficient for environmental monitoring (53 ppb by the National Ambient Air Quality Standards).