Study on humidity sensing properties based on composite materials of Li-doped mesoporous silica A-SBA-15

P-SBA-15 and A-SBA-15 and LiCl-A-SBA-15 (X) were prepared and characterized by IR and XRD. These different characteristic results suggest that these materials have the similar mesoporous structure. The dopant of LiCl improves the pure A-SBA-15 sorption ability to moisture. A resistive-type humidity sensor is fabricated on a ceramic substrate with Ag-Pd interdigital electrodes. The testing results on humidity sensing properties show that the material with 15 wt.% LiCl as a dopant has the best sensing properties to humidity. The discussion on the sensing principle suggests that the protons are the domination carrier in a low humidity range and ions in a high humidity range. The complex impedance plots support this discussion result.