DMSE professor Howard Katz’s manuscript, entitled “Enhanced and Unconventional Responses in Chemiresistive Sensing Devices for Nitrogen Dioxide and Ammonia from Carboxylated Alkylthiopene Polymers” published in Materials Horizons 2020 (

The research addresses the ongoing need to detect certain atmospheric gases that can be harmful to humans. Spaces can be made safer for people by creating warnings prompted by gases measured in a given area and by monitoring how much exposure people may have had to these gases. Katz’s group works on plastics, called “semiconducting polymers”, that change how much electricity they conduct depending on exposure to these gases. The manuscript provides a description of how certain of these plastics undergo strong and unusual changes in the presence of two of these gases, nitrogen dioxide, an air pollutant from engine exhausts, and ammonia, commonly found in cleaners and on farms.

Katz explained that “These plastics can be used in devices to provide earlier warnings about the gases, and can also increase our confidence that the warnings are truly about those particular gases.”

The goal of Katz’s research overall is to use the unique chemical properties of the semiconducting polymers to detect vapors more sensitively and precisely, as one of the challenges posed by these polymers is their sensitivity to ordinary air. The responses to the vapors of interest for the applications can be lost among the polymers’ responses to air, and so his team is now focused on two approaches to overcoming this limitation: one, designing materials with a larger comparative response to the vapors of interest; and two, putting more than one of the devices in an electrical circuit that preserves or amplifies the response to these vapors while canceling out air-sensitive responses.

Katz was the first to propose the use of semiconducting polymers to detect multiple vapors back in the early 2000’s while still working in his previous position at Bell Laboratories. He has worked in this field ever since. Katz has four patents and this manuscript is one of about two dozen publications he has done on the topic. His team expects a few more from this research in the near future.

Congratulations to Howard Katz, lead author Justine Wagner, and team members Hyun-June Jang and Dr. Jinfeng Han for the recognition by Materials Horizons and for all their hard work in the field of vapor sensors to advance human health.