Development of polyaniline-WO3-CuCl2 gas sensor on a flexible plastic substrate for humidity-insensitive detection of hydrogen sulfide gas

摘要

Simple and low-cost hydrogen sulfide gas sensors based on polyaniline-CuCl_2 and polyaniline-WO_3 -CuCl_2 composites were developed. The sensing film was produced by Drop cast of the dispersed composite on top of screen printed interdigitated carbon electrodes on a flexible polyethylene terephthalate substrate. A fast response time of ～ 10 s to ～20 s was obtained for 0.1 ppm of hydrogen sulfide. The calibration curve displays a good working range between 0.1 and 1 ppm with a limit of detection and limit of quantification of 28 ppb and 95 ppb, respectively. The polyaniline-CuCl_2 sensor presented a high response to humidity change. In contrast, the incorporation of tungsten oxide into the polyaniline-CuCl_2 composite was nearly insensitive to humidity change and exhibited significantly improved response to target gas. Gas-sensing tests show that polyaniline-WO_3-CuCl_2 composites exhibit a high and fast response as well as an excellent selectivity to hydrogen sulfide at ppm level in room temperature. The proposed sensors can be used for different industrial applications.