Electrical characterization of room temperature humidity sensors in La_(0.8)Sr_(0.2)Fe_(1-x)Cu_xO_3 (x = 0, 0.05, 0.10)

摘要

Semiconducting oxide gas sensors based on La_(0.8)Sr_(0.8)Fe_(1-x)Cu_xO_3 (x = 0, 0.05, 0.10) (LSF, LSFCO_5, and LSFCIO, respectively) were prepared by screen-printing for humidity detection at room temperature. The thick-films were heat-treated at 800, 900 and 1000 °C for 1 h and all the compositions proved to be effective in humidity sensing and presented a good reproducibility between several measurements. However, the best results were obtained with LSFCIO fired at 800 °C which showed a detection limit of 15% relative humidity and a maximum sensor response of about 87%, higher than the previous results. Copper addition to lanthanum strontium ferrites proved to be effective in lowering the sensors' detection limit.