In this work we use a combination of 3D-TEM tomography, energy filtered TEM, single molecule DNA translocation experiments, and numerical modeling to show a more precise relationship between nanopore shape and ionic conductance and show that changes in geometry while in solution can account for most deviations between predicted and measured conductance. We compare the structural stability of Ion Beam Sculpted (IBS), IBS-annealed, and TEM drilled nanopores. We demonstrate that annealing can significantly improve the stability of IBS made pores. Furthermore, the methods developed in this work can be used to predict pore conductance and current drop amplitudes of DNA translocation events for a wide variety of pore geometries. We discuss that chemical dissolution is one mechanism of the geometry change for SiNx nanopores and show that small modification in fabrication procedure can significantly increase the stability of IBS nanopores.

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 [MeSO 4 Rising environmental concerns have led to the development of sensors to monitor environmental conditions such as CO 2 , VOC's, particulate matter, temperature, and relative humidity (RH). Humidity sensing finds its usage in a broad range of applications for indoor air quality monitoring in HVAC systems and automobiles, weather monitoring in meteorological stations, greenhouse gas monitoring systems, and textile quality monitoring. Three basic sensor types that have been widely used in commercial and industrial space are capacitive, resistive, and thermal humidity sensors.1 Over the years, variety of sensing materials such as ceramics, semiconductors, polyelectrolytes, and polymers have been explored and utilized in humidity sensors.2 Current challenges faced in humidity sensing are sensor drift, accuracy and reproducibility at increased humidity, response time of the sensor, power consumption, and long-term usability.3 These challenges necessitate the development of a new material system for next generation humidity sensing.We employ a unique sensing material system-Room temperature ionic liquid (RTIL) to develop a robust humidity sensor toward making it suitable for commercial applications. Room temperature ionic liquids (RTILs) are a class of materials that have been studied for over a century. They have been shown to be useful in several different applications from gas sensing to protein stabilizers in biological experiments.4,5 Their highly ionic nature, wide electrochemical window, and ideal thermal and physical properties (See Table I) are ideal for the development of new electrochemical based humidity sensor. 4 This class of materials consists of two major components; an organic cation and inorganic anion. These two components can be tuned depending upon what application the material is being investigated. Bridgeman et al. have previously demonstrated a calorimetric humidity sensor using ionic liquid membranes for food and pharmaceutical quality monitoring.7 Due to the pure ionic nature of RTILs, when a voltage is applied, this material has shown promise as a potential electrochemical based sensor. The innovation of this study is to interface an RTIL with a sensing platform which results in the formation of multi stack electrochemical double layer (EDL). 8,9 The charge distribution in the EDL as a result of water adsorption is studied through an AC = These authors contributed equally to this work.* Electrochemical Society Student Member. z E-mail: shalini.prasad@utdallas.ed...

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Rising environmental concerns have led to the development of sensors to monitor environmental conditions such as CO 2 and relative humidity (RH). Requirement of sensor performance metrics such as low power, high stability, increased sensitivity has led to the investigation of RTIL as a suitable candidate for environmental sensing. A versatile, robust electrochemical duplex sensor for the detection of CO 2 and humidity using a novel sensing material -Room temperature ionic liquid (RTIL) is presented. RTILs interfaced with a sensing electrode platform results in the formation of multiple electrochemical double layers (EDL). AC perturbation of the system causes charge redistribution in the EDL because of CO 2 and water adsorption which is studied through an AC based technique-Electrochemical impedance spectroscopy. The frequency response of the EDL provides an insight of the impedance changes of the EDL as the environment changes around them. The effects of CO 2 concentrations and RH levels across temperatures on three RTILs -MMIM [MeSO 4 ], EMIM[TF 2 N] and EMIM [FAP] have been investigated. Furthermore, the adsorption/desorption dynamics of the best performing RTILs were evaluated to understand the repeatability in CO 2 sensing behavior. RTILs have the potential to be integrated with semiconductor technology for the sensitive detection of CO 2 concentrations and humidity ranges across varying temperatures. Hence, it has the potential of a new strategy for achieving low power environmental sensors.