Effect of surfactant on performance of ZnO humidity sensor

In this study, using surfactant monoethanolamine (MEA), zinc oxide (ZnO)-MEA humidity sensor based on ZnO was successfully prepared by hydrothermal method. MEA makes the surface of the ZnO-MEA have more oxygen vacancy and hydrophilic functional groups, which improves the performance of ZnO humidity sensor. ZnO-MEA achieved a change of 4 orders of magnitude at room temperature in the relative humidity (RH) from 11% to 95%, and it shows better linearity, shorter response/recovery time (20 s/15.9 s), smaller humidity lag and long-term stability. In addition, the distribution of ZnO-MEA particles is more uniform and provides more active sites for adsorption of water molecules to enhance humidity sensing performance.