Environmental sensors are a step closer to simultaneously sniffing out multiple gases that could indicate disease or pollution, thanks to a Penn State research. Huanyu \u201cLarry\u201d Cheng, assistant professor of engineering science and mechanics in the College of Engineering, and Lauren Zarzar, assistant professor of chemistry in Eberly College of Science, and their teams combined laser writing and responsive sensor technologies to fabricate the first highly customizable microscale gas sensing devices.<\/p>\n
They published their technique this month in\u00a0Applied Materials & Interfaces<\/em>, a journal of the American Chemical Society.<\/p>\n \u201cThe detection of gases is of critical importance to various fields, including pollution monitoring, public safety assurance and personal health care,\u201d Cheng said. \u201cTo fill these needs, sensing devices must be small, lightweight, inexpensive and easy to use and apply to various environments and substrates, such as clothing or piping.\u201d<\/p>\n According to Cheng, the challenge is creating devices with the desired properties that still can be tailored with the infrastructure needed for precise and accurate sensing of different target gases at the same time. That\u2019s where Zarzar\u2019s expertise with laser writing comes in.<\/p>\n \u201cLaser writing techniques give design freedom to a wide range of fields,\u201d Zarzar said. \u201cExpanding our understanding of how to directly synthesize, pattern and integrate new materials \u2014 especially nanomaterials and nanomaterial composites \u2014 into complex systems will allow us to create increasingly more sophisticated and useful sensing technologies.\u201d<\/p>\n Her research group developed the laser-induced thermal voxel process, which enables the simultaneous creation and integration of metal oxides directly into sensor platforms. Metal oxides are materials that react to various compounds, triggering the sensing mechanism. With laser writing, the researchers dissolve metal salts in water, then focus the laser into the solution. The high temperature decomposes the solution, leaving behind metal oxide nanoparticles that can be sintered onto the sensor platform.<\/p>\n The process streamlines previous methods, which required a pre-defined mask of the planned pattern. Any changes or adjustments required the creation of a new mask \u2014 costing time and money. Laser writing is \u201cmaskless,\u201d according to Zarzar, and, when combined with the thermal voxel process, it allows for the rapid iteration and testing of multiple designs or materials to find the most effective combinations.<\/p>\n \u201cPrecise patterning is also a necessary component for the creation of \u2018electronic noses,\u2019 or arrays of sensors that act like a nose and can precisely detect multiple gases at the same time,\u201d said Alexander Castonguay, graduate student in chemistry and co-first author on the paper. \u201cSuch precise detection requires the patterning of different materials in close proximity, at the thinnest microscale. Few patterning techniques have the resolution to do this, but the approach detailed in this study does. We plan to use the techniques and materials described here to develop electronic nose prototypes.\u201d<\/p>\n The researchers tested five different metals and metal combinations\u00a0 currently used in sensors. According to Castonguay, the point where different metal oxides touch, called a heterojunction, cultivates a unique environment at the interface of the two materials that enhances the response of gas sensors. The team found that a heterojunction of copper oxide and zinc oxide has a five to 20-fold enhanced response to the tested gases \u2014 ethanol, acetone, nitrogen dioxide, ammonia and hydrogen sulfide \u2014 over just copper oxide.<\/p>\n \u201cThis 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,\u201d Castonguay said. \u201cWe hope by pooling the laser writing knowledge of the Zarzar group with the wearable sensor expertise of the Cheng group, we will be able to expand our capabilities to create novel, customizable sensors.\u201d<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Environmental sensors are a step closer to simultaneously sniffing out multiple gases that could indicate disease or pollution, thanks to a Penn State research. Huanyu \u201cLarry\u201d Cheng, assistant professor of engineering science and mechanics in the College of Engineering, and Lauren Zarzar, assistant professor of chemistry in Eberly College of Science, and their teams combined […]<\/p>\n","protected":false},"author":2,"featured_media":4436,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[212],"tags":[358,437,436,415],"featured_image_src":{"landsacpe":["https:\/\/cirrus-centar.hr\/wp-content\/uploads\/2022\/07\/laser3-1000x445.jpg",1000,445,true],"list":["https:\/\/cirrus-centar.hr\/wp-content\/uploads\/2022\/07\/laser3-463x348.jpg",463,348,true],"medium":["https:\/\/cirrus-centar.hr\/wp-content\/uploads\/2022\/07\/laser3-300x225.jpg",300,225,true],"full":["https:\/\/cirrus-centar.hr\/wp-content\/uploads\/2022\/07\/laser3.jpg",1000,750,false]},"_links":{"self":[{"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/posts\/4441"}],"collection":[{"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/comments?post=4441"}],"version-history":[{"count":0,"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/posts\/4441\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/media\/4436"}],"wp:attachment":[{"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/media?parent=4441"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/categories?post=4441"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cirrus-centar.hr\/en\/wp-json\/wp\/v2\/tags?post=4441"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}