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Peter Kruse Peter Kruse
Professor of Chemistry
McMaster University

Dipl. Chem. (Friedrich Schiller University, Jena)
Ph.D. (University of California, San Diego)

Surface Science
2-Dimensional Materials
Interfacial Doping in Electronic Materials
Water Quality Sensors
Department of Chemistry and Chemical Biology
McMaster University
1280 Main St.W.
Hamilton, Ontario
Canada L8S 4M1

email: pkruse @
Phone: +1(905)525-9140 (+ext.)
Office: ABB-420 (ext. 23480)
Lab: ABB-AB101 (ext. 26322)
Lab: ABB-466C (ext. 23265)

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We are surface scientists, interested in understanding phenomena that arise from the atomic-scale interplay between electronic structure and chemical reactivity at surfaces and interfaces, in thin films and 2-dimensional structures. Surface science is fascinating due to its interdisciplinary nature and due to the proximity of fundamental studies and applications. Most of the important processes in living organisms happen at interfaces. One might define nanotechnology as the study of materials whose bulk properties are dominated by their interfaces. Surfaces are complex systems (Wolfgang Pauli: "Solids were made by god, but surfaces are the work of the devil."), yet they can be studied systematically if one chooses the right systems. Over the years our research group has worked on a range of different 2D systems that promise interesting science along with relevant applications, including gold-covered oxidized GaAs substrates for nanowire growth; doping of carbon nanotubes (CNTs); mechanisms of corrosion inhibition on steel and magnesium alloys using oligoanilines; nanoscale pattern formation during electropolishing; nanostructured anodic oxide films; switchable interfacial dopants and water quality sensors.

More recently, combining our knowledge about doping of CNTs and about redox-switchable conjugated systems (oligoanilines), we developed the concept of a chemiresistive free chlorine sensor based on tetra-aniline-doped CNT networks. Conductive random percolation network films of single-walled CNTs are deposited between two contacts and partially exposed in a microfluidic channel. The conductivity of the CNT films is strongly dependent on whether they have been exposed to molecules that modify their electronic structure due to the formation of charge transfer complexes. This property was exploited in previous sensor designs with the analyte as a dopant (e.g. NH3), but those sensors suffer from selectivity issues (many different dopants have the same impact on conductivity) and resettability challenges (requiring the physical removal of the analyte dopant e.g. by heating). Our chlorine sensor design differs in that it utilizes permanently attached transducer molecules that are switched between at least two different stable states in response to an environmental stimulus, such as an oxidant with a redox potential above a certain threshold. In collaboration with Prof. Selvaganapathy (McMaster, Mechanical Engineering) we developed this concept into usable sensor devices and started collaborating with interested companies. The concept can be expanded to different substrates (exfoliated graphene, pencil trace, graphene-like carbon films, MoS2) and analytes (e.g. cations, anions, pH, other disinfectants). The conducting form of MoS2 that we have developed for our chemiresistive films can have many other uses in electrocatalysis or energy storage materials. At present - and in the foreseeable future - the work in our group is focussed on 2D materials. Currently we are studying the properties of thin films fabricated from both few-layer graphene, graphene-like carbon and conducting MoS2 for applications in chemiresistive sensor devices, but the scope of our work may expand to other stable 2D materials and other applications.

(pk) 06 November 2021