Thanks to a Penn State collaboration, environmental sensors are a step closer to detecting multiple gases that could indicate disease or pollution. Lauren Zarzar, assistant professor of chemistry in Eberly College of Science, and her team collaborated with Larry Cheng, assistant professor of engineering science and mechanics in the College of Engineering, to create the first highly personalized microscale gas sensors.
Their technique was published in the journal.
Pollution monitoring, public safety assurance and personal health care are all areas where the detection of gases is important. To fill these needs, small, lightweight, inexpensive and easy to use devices are needed.
The challenge is to create devices with the desired properties that still can be tailored with the infrastructure needed for precise and accurate sense of different target gases at the same time. Zarzar has experience with laser writing.
Design freedom can be given to a wide range of fields with the use of laser writing techniques. Our understanding of how to synthesise, pattern and integrate new materials will allow us to create more sophisticated and useful sensor technologies.
The laser-induced thermal voxel process was developed by her research group. The material metal oxides reacts to various compounds. The researchers use a laser to focus the laser into the solution. The high temperature leaves behind metal oxide particles that can be used to make a sensor platform.
The process eliminates the need for a pre-defined mask. The creation of a new mask was needed for any changes. Zarzar says that laser writing is "maskless" and that it can be combined with the thermal voxel process to find the most effective combinations.
Alexander Castonguay is a graduate student in chemistry and co-first author on the paper. The patterning of different materials in close proximity is required to detect it. There are few patterning techniques that have the resolution to do this. The materials and techniques described here will be used to develop electronic nose prototypes.
Five different metals were tested. The point where different metal oxides touch, called a Heterojunction, creates a unique environment at the interface of the two materials that enhances the response of gas sensors, according to Castonguay. The team found that a combination of copper oxide and zinc oxide has an enhanced response to some gases.
"This finding supports other reports in the scientific literature that the creation of mixed oxide systems can lead to significant increases in sensor response and demonstrates the efficacy of the laser-induced thermal voxel technique for mixed-oxide gas sensor fabrication." We hope that by pooling the laser writing knowledge of the Zarzar group with the Cheng group, we will be able to create novel, custom sensors.
More information: Alexander C. Castonguay et al, Direct Laser Writing of Microscale Metal Oxide Gas Sensors from Liquid Precursors, ACS Applied Materials & Interfaces (2022). DOI: 10.1021/acsami.2c03561 Journal information: ACS Applied Materials and Interfaces
All Rights Reserved © 2024
