Humidity sensor based on AlPO4-5 zeolite with high responsivity and its sensing mechanism

AlPO4-5 zeolite was successfully employed in a resistance type humidity sensor. AlPO4-5 zeolite humidity sensor was fabricated by coating nanosized materials over interdigitated electrodes. The sensor shows good linearity over a relative humidity (RH) range from 11% to 95%. At the frequency of 100 Hz, response and recovery time are both about 2 s, and the maximum hysteresis is <3%. In nanoscale confinement range, the sorbed water quantity in AlPO4-5 channels is exceptionally large and the water sorption phenomenon looks like “capillary condensation” phase transition. The complex impedance at different RH was investigated to understand the sensing mechanism. The results indicate the potential application of AlPO4-5 zeolite for fabricating high-performance humidity sensors.