Highly sensitive humidity sensors based on Sb-doped ZnSnO3 nanoparticles with very small sizes

Abstract

Highly sensitive and fast responding humidity sensors were fabricated based on Sb-doped ZnSnO₃ fine nanoparticles, which were synthesized via a dual-hydrolysis-assisted liquid precipitation reaction and subsequent hydrothermal procedure. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-visible spectrophotometry. The results demonstrated that ZnSnO₃ nanocubes evolved into Sb-doped ZnSnO₃ nanoparticles with doping by Sb. This evolution facilitated their application in humidity sensing. At room temperature, the resistance of the humidity sensors based on Sb-doped ZnSnO₃ at 30% relative humidity (RH) was 130 times greater than that in air with 85% RH. The response and recovery times were 7.5 s and 33.6 s, respectively, when the sensors were switched between 30% and 85% RH. These results are much better than those reported so far. The present results may present new opportunities for the practical application of high-performance humidity sensors at room temperature.