Researchers at U.S.-based Pennsylvania State University (Penn State) have developed a multi-parameter sensor that can decouple temperature and nitrogen signals in soils so that each can be measured accurately.
Measuring temperature and nitrogen levels in soil is important for agriculture systems but detecting them apart from one another is difficult to do.
The Penn State team, led by Huanyu “Larry” Cheng, James L. Henderson, Jr. Memorial Associate Professor of Engineering Science and Mechanics, designed and fabricated a high-performance sensor to completely decouple the detection of nitrogen loss and soil temperature. The multi-parameter sensor is based on vanadium oxide-doped, laser-induced graphene foam. Vanadium oxide can adsorb and interact with nitrogen gases, and doping metal complexes in graphene have also been found to improve gas adsorption and detection sensitivity.
The sensor is encapsulated by a soft membrane that blocks nitrogen gas permeation so the sensor responds only to temperature variations. Additionally, the encapsulation can be removed and the sensor operated at an elevated temperature. Doing so removes the influence of relative humidity and temperature in the soil to allow for accurate measurement of the nitrogen gas. The combination of the encapsulated sensor and the unencapsulated sensor can completely decouple temperature and nitrogen gas without interference.
Decoupling temperature variations and nitrogen gas emissions can be leveraged to design and apply multimodal devices with decoupled sensing mechanisms for precision agriculture in all weather conditions, according to Cheng.
“The capability to simultaneously detect ultra-low nitrogen oxide concentrations and small temperature changes paves the way for the development of future multimodal electronic devices with decoupled sensing mechanisms for precision agriculture, health monitoring and other applications,” Cheng noted.
Cheng’s work was supported in part by the National Institutes of Health, the National Science Foundation and Penn State. The National Natural Science Foundation of China, the Key Research and Development Project of Hebei Province and the China Postdoctoral Science Foundation also provided support.
Co-authors include Ankan Dutta, doctoral student of biomedical engineering at Penn State; Li Yang, Xue Chen, Shuaijie Du, Shiji Guo, Chuizhou Meng, Guangyu Niu, Ya Wang, Ye Xue and Jaiya Yan, all affiliated with Hebei University of Technology, China; Cheng Zhang, Minjiang University, China; and Peng Zhou, Tiajin Tianzhong Yimai Technology Development Co. Ltd., China.
Photo: Huanyu “Larry” Cheng, James L. Henderson, Jr. Memorial Associate Professor of Engineering Science and Mechanics in Penn State's College of Engineering. (Credit: Kelby Hochreither/Penn State)
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