The collaboration between the researchers of the Technical University of Moldova and those of universities in Germany, the Netherlands, and Great Britain, recently concluded with the publication of a large-scale scientific paper of 27 pages in the prestigious journal “Journal of Materials Chemistry A” , 2020, 8, 16246–16264, with impact factor 11.3, the respective article being selected for the front cover of the magazine.!divAbstract

These remarkable results are due to the fruitful collaboration of the teams led by prof., Dr. Oleg LUPAN – Center for Nanotechnologies and Nanosensors, Department of Microelectronics and Biomedical Engineering within UTM; prof., Dr. Franz FAUPEL – Christian Albrechts University of Kiel, Germany; prof., Dr. Rainer ADELUNG – Institute for Materials Science, Germany; prof., Dr. Lorenz KIENLE – Faculty of Engineering, Kiel University, Germany; prof., Dr. Nora H. de LEEUW – Utrecht University in the Netherlands and Dr. David SANTOS-CARBALLAL – University of Leeds, Great Britain, over the years.

As batteries are increasingly used in various equipment as portable energy sources, especially in modern cars, their volume and complexity is constantly increasing. Under market conditions, manufacturers are constantly improving them, especially Li-ion batteries, based on lithium ions. Various new, essentially improved chemical combinations occur every few months, and with such rapid progress, it is difficult to assess the degree of “aging” of a battery, how it behaves, but also the degree of safety during operation. Hence the urgent need for precision sensors, with an extended life, for the respective batteries.

For fast and reliable monitoring of hazardous environments around batteries, the detection of volatile organic compounds (VOCs)  in the low ppm range is critically important and requires the development of new chemical sensors. The authors of the respective scientific paper reported a new approach, in order to tailor the selectivity of sensors based on nanocomposite thin films, by systematically investigating the effect of the surface decoration of the ZnO:Ag columnar thin films. For the decoration of ZnO:Ag surfaces, AgPt and AgAu noble bimetallic alloy nanoparticles were used, and the resulting gas sensing properties were measured, particularly towards VOC vapors and hydrogen gas. As such, NP-decorated ZnO:Ag thin film sensors should be suitable for the detection of H2 in Li-ion batteries, which is an early indication of thermal runaway leading to complete battery failure and possible explosion. Therefore, the sensors developed by the team led by Dr. Oleg LUPAN, UTM, in collaboration with researchers from the Kiel University and the Institute for Materials Science, can be mounted on various equipment with batteries, to prevent damage, or even explosion.

To understand the impact of NP surface decoration on the gas sensing properties of ZnO:Ag thin films, the team led by prof. Nora H. de Leeuw from Utrecht University, the Netherlands, and Dr. David Santos-Carballal, University of Leeds, Great Britain, used density functional theory calculations with on-site Coulomb corrections and long-range dispersion interactions (DFT+U–D3-(BJ)) to investigate the adsorption of various VOC molecules and hydrogen onto the sensor surface. The theoretical results confirmed the experimental ones and attracted the attention of the reviewers and the magazine editor, who selected these results to be presented on the cover of the magazine, thus the image of UTM prevailing internationally.

The scientific paper to which we refer is part of a broader research on “Nanotechnologies for nanosensory devices”, conducted under the scientific guidance of Dr. Oleg LUPAN. Students from the university cycles I, II, and III can join the team of the Center for Nanotechnologies and Nanosensors, the Department of Microelectronics and Biomedical Engineering, Faculty of Computers, Informatics and Microelectronics of UTM, and thus benefit from the opportunity to test their knowledge by developing new electronic and biomedical devices, but also to engage in international collaborations.

This internationally acclaimed research was partially supported by the NATO Science for Peace and Security Programme (SPS) Project under grant G5634 “Advanced Electro-Optical Chemical Sensors” AMOXES, conducted at the Technical University of Moldova.

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