Chemiresistive Sensors for Application in Aqueous Environments

Title

Chemiresistive Sensors for Application in Aqueous Environments

Speaker

Prof. Peter Kruse (McMaster University, Canada)

Host

Prof. Kai Huang (GTIIT, Chemistry)

Time and Location

Jun. 24 2022, Friday, 9:00am-10:00am(China Time),  E211 (Education Building, 2nd floor)

Language

English

Zoom Link

https://gtiit.zoom.us/j/94609938903

Abstract

Chemiresistors are solid state devices that change their electronic properties as a result of chemical interactions with their environment. They are a well-established and widely commercialized technology for gas or vapor sensor applications. Water quality sensors are a surprisingly underserved area of sensor applications. Important chemical water quality parameters include pH, dissolved gases, common ions and a range of toxic trace contaminants which may be ionic or uncharged, inorganic or organic. They are usually monitored using colorimetric or electrochemical sensors, and large lab-based instruments. These methods suffer from high maintenance, need for reagents, high power needs, or inability to operate autonomously and continuously. Chemiresistors have the potential to eliminate all these disadvantages, but there has been slow progress in adapting them to aqueous analytes. Challenges include the need to prevent electrical shorts through the aqueous medium and the need to keep the sensing voltage low enough to avoid electrochemical reactions at the sensor. The active sensor elements in our devices consist of a percolation network of low-dimensional materials particles that form a conducting film, e. g. from carbon nanotubes, pencil trace, and different forms of graphene or graphene oxide. These networks can be made selective by 3 principal approaches: (1) by introduction of chemical defects into the network itself, (2) by functionalizing the network with switchable dopant molecules, or (3) by coating the network with selective membranes. After demonstrating free chlorine sensors using the second approach, we have also introduced pH sensors and ion sensors. While there are some challenges associated with expanding the range of accessible analytes, we have recently exploited all three principal approaches to expand the applicability of our platform, in particular to anions and cations.

Biography

Dr. Peter Kruse is a Full Professor of Chemistry at McMaster University in Canada. He completed his Diploma in Physical Chemistry from Friedrich Schiller University Jena in Germany in 1995. His undergraduate experience also included a year abroad, spent at the University of Strathclyde in the UK and work placements at Wellcome Research Laboratories in the UK (synthesizing antiviral drug candidates) and at IMEC in Belgium (optimizing cleaning procedures for silicon wafers). His undergraduate thesis on “1H and 13C nuclear spin relaxation of liquid methyliodide: Separation of inter- and intramolecular contributions.” was completed under supervision of Prof. Karl-Ludwig Oehme. He started graduate school with Prof. Phillip Kash at the University of British Columbia in Canada, but then moved to the University of California, San Diego in the USA to complete his PhD thesis on “Reactions of oxygen on GaAs(100)” in 2000 under supervision of Prof. Andrew Kummel. He then worked for two years as a postdoctoral fellow with Drs. Robert Wolkow, Dan Wayner and Gregory Lopinski at the Steacie Institute of the National Research Council of Canada, using scanning tunneling microscopy to study the adsorption of small organic molecules on silicon surfaces. In 2002, he joined the Department of Chemistry at McMaster University in Canada as a full-time faculty member. Research in the Kruse group over the last 20 years has spanned chemical doping of carbon nanotubes, corrosion inhibition on steel, mobility at interfaces, anodic pattern formation in electrochemistry, 2D materials and chemiresistive sensors.