Humidity sensing and dielectric properties of mesoporous Bi3.25La0.75Ti3O12 nanorods

• Electrospinning technique combining with nanocasting method is used to prepare M-BLT nanorods.
• Impedance variation of the M-BLT nanorods humidity device is about six orders of magnitude at 100 Hz.
• M-BLT nanorods can be used as humidity sensor or switch by modulating the working frequency.

Bi3.25La0.75Ti3O12 (BLT) nanorods are synthesized via electrospinning technique, and mesoporous structures are formed in the BLT nanorods via nanocasting method. The mesoporous BLT (M-BLT) nanorods are characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and energy dispersive spectrometer, and then coated on the ceramic substrates with Ag-Pd interdigitated electrodes to form the humidity sensitive device. The humidity sensitive properties of M-BLT nanorods humidity sensitive device are investigated at room temperature within the relative humidity (RH) ranges of 11–95%. The impedance properties of M-BLT nanorods are effected by frequencies. The M-BLT nanorods have good sensing properties at low frequency. The humidity sensitive device is of high sensitivity at 100 Hz, and the impedance variations are over six orders of magnitude within the humidity ranges from 11% to 95% RH. The response time and recovery time of the M-BLT nanorods humidity sensitive device are about 8 s and 250 s, and the maximum hysteresis is about 4% RH. The results indicate that the electrospinning technique combining with nanocasting method would be one of important and effective approaches for preparing high-performance humidity-sensing material, and the M-BLT nanorods are the promising materials to fabricate high sensitivity humidity sensor.