A Robust Electrochemical Humidity Sensor for the Detection of Relative Humidity Using Room Temperature Ionic Liquid (RTIL) for Integration in Semiconductor IC's

Abstract

© The Author(s) 2018. Published by ECS. Humidity sensing is critical in environmental and industrial spaces to monitor air conditions for the wellbeing of the human population and to ensure favorable industrial processes such as storage and performance. In this work, we utilize room temperature ionic liquids (RTILs) as novel sensing elements toward the development of a robust electrochemical humidity sensor for integration in semiconductor technology. For this study, we report and discuss the performances of a non-fluorinated RTIL vis-a-vis a fluorinated RTIL, MMIM[MeSO4] and EMIM[TF2N], on exposure to humidity levels 25-65%RH at low (25-45°C) and elevated temperatures (65°C). The electrochemical responses of the RTILs to humidity and temperature are recorded via electrochemical impedance spectroscopy to measure the capacitance changes occurring within the electrochemical double layer. Both RTILs show similar responses to humidity levels and temperatures. This work is the first demonstration of the implementation of RTILs on micro electronic devices toward achieving rapid and sensitive humidity sensing.