Highly-sensitive potassium-tantalum-niobium oxide humidity sensor

We report moisture sensitive properties of ferroelectric niobium-rich potassium tantalate K [(Ta0.2Nb0.8)(0.99)Mn-0.01]O-3 (KTN) which shows giant humidity response with excellent reproducibility and repeatability of data as a function of exposure time and humidity contents. Many fold change in resistance was observed with change in the relative humidity (Rh) from 15% to 95% which provides maximum sensitivity ((4) over tilde 600) at 298 K in the presence of Rh 95%. It also shows polarity dependent change in resistance with nearly 310 to 513 mV in-built potential depending on the device configuration. The polar KTN humidity sensor shows a decrease in resistance with an increase in Rh% which favors the Grotthuss mechanism responsible for humidity effects. To improve the sensitivity, a particular device configuration has implemented for the homogeneous interaction of the water vapor molecule with a maximum active sensor-surface area. The electronics with the digital display unit was designed and developed to represent the relative humidity in the form of digital display. (C) 2019 Elsevier B.V. All rights reserved.