Thesis defence S. Sachdeva: gas sensing

27 March 2017 | 15:00
location: Aula, TU Delft
by Webredactie

Gas Sensing by Metal Organic Framework based CMOS Platforms. Promotor 1: Prof.dr. E.J.R. Sudhölter (TNW), Promotor 2: Prof.dr. J. Gascon (TNW).

This thesis describes a study on gas-phase sensing using capacitive transducers coated with selective affinity layers containing Metal-Organic Frameworks (MOFs). Gas sensing plays an important role in applications such as detection of toxic gases, medical diagnostics and environment monitoring. In order to improve the sensitivity and selectivity of existing sensor devices, MOFs-based affinity layers can be potential candidates due to their selective and tunable nature. The capacitive transducers detect changes in the dielectric properties of the affinity layers as a result of interactions with the analyte. Transducers used in this study belong to the class of planar electrodes having a geometry as either interdigitated electrodes or as meander-patterned electrodes. The precise geometry of these transducers determines the electrical field strength through the affinity layer, which, in turn, affects the sensitivity of the device. Besides the transducer geometry, thermodynamics and kinetics of the interaction between the analyte and affinity layer also contribute to the sensitivity and selectivity of the sensor devices. MOFs, being porous solid materials with tunable structural and functional properties, add gas sensitivity and selectivity when integrated with the transducer devices. The fabrication of such MOF-based affinity layers in this study was achieved following two different approaches: (i) in-situ electrochemical synthesis and (ii) deposition of MOF-polymer composites. With both approaches, the capacitive sensing behavior towards gas-phase analytes resulted in sensitive, stable and reversible response. With vast library of MOFs and polymers and ease of integration with the semiconductor industry, this work can provide a valuable base for the MOF-based electronic devices for sensing applications.

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