Papers by Author: Ho Cheng Lee

Abstract: This study presents a simple and low-cost spray coating process for producing high performance CO (carbon monoxide) sensors utilizing toluene-based gold nanoparticles (Au-NPs). Thanks to the success synthesis of Au-NPs in toluene, this low surface tension organic solvent prevents Au-NPs from colligation. And therefore Au-NPs can be well dispersed on the surface of the electrodes as the sensing layer during spraying. To compare with the typical metal oxide based CO sensors that have to work at a higher working temperature of about 150~350°C, the produced sensor can work at room temperature and have a better detection limit for CO gas (5 ppm). Experimental results indicate good linear sensitivity under repeated measurements for concentration range from 5 250 ppm (R²=0.996). The repeatability is also confirmed by measuring 100 ppm CO gas, the calculated variation is less than 2.8% for six repeating measurements. The process developed in this study can be used to produce not only high performance CO gas sensors but other related gas sensors.