A novel humidity sensor based on NH2-MIL-125(Ti) metal organic framework with high responsiveness

A novel porous nanosized humidity-sensing material of amine-functionalized titanium metal organic framework (MOF), NH2-MIL-125(Ti), was investigated. NH2-MIL-125(Ti) nanoparticles with high phase purity and good physicochemical property were synthesized by a simple hydrothermal method. The nanosized MOF was characterized by X-ray diffraction and scanning electron microscope. The average size of the MOF nanoparticles is around 300 nm. Then NH2-MIL-125(Ti) humidity sensor was fabricated by coating the nanosized materials on interdigitated electrodes. The humidity sensor based on NH2-MIL-125(Ti) shows good linearity of RH (11-95 % RH), as well as fast response and recovery time. The RH detecting range is from 11 to 95 % RH at 100 Hz. The response and recovery time are about 45 and 50 s, respectively. Moreover, the sensing mechanism was discussed by complex impedance analysis in detail. These results indicate the potential application of NH2-MIL-125(Ti) in humidity sensors.