A humidity sensor based on KCl-doped nanoporous Ti0:9Sn0:1O2 thin films prepared by the solgel method

A humidity sensor based on kcl-doped nanoporous ti0:9sn0:1o2 has been developed by thesolgel method and pluronic p123 as the organic template on alumina substrates, and their humiditysensing properties have also been also investigated at different sintering temperatures. it is found that50 mol% kcl doped nanoporous ti0:9sn0:1o2 thin film, sintered at 500 ,c for 4 h, shows the best humiditysensing properties, and its impendence decreases more than four orders of magnitude from 109 to 105 with good linearity in the relative humidity (rh) range of 11%95% at 25 ,c. the response and recoverytime of this sensor are about 11 and 14 s, respectively. high sensitivity, narrow hysteresis loop, rapidresponse and recovery, prominent stability and good repeatability are obtained. a possible mechanism issuggested to explain the humidity sensitive properties.