Humidity Effect on Transport Properties of Titanium Dioxide Nanoparticles

Rutile TiO2 nanoparticles were synthesized using co-precipitation method with an average diameter of 30 nm TiO2 nanoparticle device was then fabricated on glass substrate.Aluminum electrodes were defined using photolithography and vacuum evaporation.A suspension of TiO2 nanoparticles was prepared in isopropanol using ultrasonic agitation.The nanoparticles were deposited between the electrodes.The device was tested by AC electrical measurements at 40%-90%relative humidity（RH）.The impedance of the TiO2nanoparticles decreases by about 80 times with the increase in RH from 40%to 90%at 100 Hz.The response time and the recovery time were 4 s and 5 s,respectively between 40%and 90%RH.At 100 Hz,the sensitivity of the aluminum electrode TiO2 nanoparticle device in the range of 40%—90%RH was17 MΩ/%RH.Complex modulus analysis also confirms the increase in DC conductivity of TiO2 nanoparticles as RH increases.