A novel humidity sensor based on Na2Ti3O7 nanowires with rapid response-recovery

Na2Ti3O7 nanowires have been synthesized by a simple hydrothermal method, and characterized by X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The sensor fabricated from these Na2Ti3O7 nanowires shows high humidity sensitivity and rapid response-recovery. The impedance of the sensor decreases by about four orders of magnitude with increasing relative humidity (RH) from 11 to 95%. The response time of the sensor from 25 to 95% RH is about 4 s, and the corresponding recovery time is about 5 s. These results indicate the potential application of the Na2Ti3O7 nanowires for fabricating high-performance humidity sensors.