A rapid-response humidity sensor based on BaNbO3 nanocrystals

Perovskite niobate (BaNbO3) nanocubes have been synthesized for the first time by using the composite-hydroxide-mediated method. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). Humidity sensors based on BaNbO3 nanocubes were fabricated. The responsiveness to humidity for static and dynamic testing proved the ultrasensitive properties of the sensors. The resistance changed from 932.4 MΩ to 2.2 MΩ as the relative humidity (RH) increases from 10% to 80%. The response-time and recovery-time of the resistance is 12 s and 32 s versus the changes of relative humidity from 20% to 60%. These results indicate promising applications of BaNbO3 nanocubes in a highly sensitive environmental monitoring and humidity controlled electronic device.