Materials Horizons Emerging Investigator Series: Evgeniya Sheremet, Tomsk Polytechnic University, Russia

Prof. Evgeniya Sheremet is a co-founder and co-leader of the TERS-team (http://ters-team.com) research group at Tomsk Polytechnic University, Russia. The group is working on carbon and plasmonic nanomaterials, their applications in biomedicine and flexible electronics, and developing advanced methods for nanoscale analysis. Prof. Sheremet completed her postdoctoral work in 2017 in the Solid Surfaces Analysis group and defended her PhD in 2015 in the Semiconductor Physics group at Chemnitz University of Technology, Germany. Previously, she studied Nanotechnology at Novosibirsk State Technical University and performed research at the Institute of Semiconductor Physics, Novosibirsk, Russia. She received the National L’Oréal-UNESCO award for Women in Science (2019), as well as a regional award in 2017 for her scientific contribution to experimental physics.

Read Evgeniya Sheremet's Emerging Investigator Series article “Beyond graphene oxide: laser engineering functionalized graphene for flexible electronics” and read more about her in the interview below:

MH: Your recent Materials Horizons Communication focuses on laser processing of single-layer diazonium-functionalized graphene for graphene-device fabrication. How has your research evolved from your first article to this most recent article and where do you see your research going in the future?

ES: My research work started in developing surface- and tip-enhanced Raman spectroscopy for nanomaterial analysis, including carbon nanotubes and quantum dots. Shortly after, my colleague, Prof. Raul D. Rodriguez started working on laser-modification of graphene oxide (GO), while I investigated its nano-Raman spectra and nanoscale imaging. GO is a graphene sheet with various oxygen-containing groups disturbing the carbon lattice, making the material a semi-transparent dielectric. When a laser illuminates a sample, these functional groups are removed and the C=C bonds are restored, making the material conductive again. Three years ago we jointly established a research group at Tomsk Polytechnic University. Here we looked into GO surface potential, defect concentration, and high-order Raman modes, but we weren't able to achieve high electrical conductivity in a single laser-reduction step. One of our PhD students had a hypothesis that the substrate used during laser processing of graphene oxide determines the degree of reduction. We then started looking at the effects of substrate properties on laser reduction and discovered that the interface is modified due to laser heating. At the same time, the idea came up that diazonium-functionalized graphene could be turned from a dielectric to a conductor by laser processing. We hypothesized that just like the oxygen-containing groups in GO, the functional groups in modified graphene would be removed by laser irradiation, restoring the high conductivity of graphene. We were surprised that despite the intensive research on diazonium functionalization of graphene no-one had investigated that before. The laser modification indeed gave up to three orders of magnitude better conductivity. By bringing these two pieces together, it was possible to create a conductive composite structure on the polymer surface that proved to be highly resilient to water and scratching. It is especially important to our general vision for biocompatible electronics that they should fulfil all those requirements but also prove to be non-toxic and mechanically flexible.

MH: What aspect of your work are you most excited about at the moment?

ES: Now we are looking at the fact that the laser processing we report in our work also induces composite formation using the polymer material as a substrate, and that the process turns out to be universal. This opens a range of exciting possibilities for using different conductive materials and substrate polymers for flexible electronics applications. The process is also scalable and we are certain that plenty of applications will emerge from it.

MH: In your opinion, what are the most important questions to be asked/answered in this field of research?

ES: For us, it is most important to realize the finest control possible of the material’s properties and test the limits of the technology’s applicability and the advantages over conventional materials. Is it possible to adjust the conductivity type and how precisely can it be controlled? Can we create a complete elemental base – not only conductors and resistors, but also inductive elements and supercapacitors – with this technology? Where are the applicability limits; can we develop competitive biocompatible materials, antennas, and wearables?

MH: What do you find most challenging about your research?

ES: The hardest thing is to decide where to focus the effort. There are so many questions and possibilities at each step of the way, and time and resources are limited.

MH: At which upcoming conferences or events may our readers meet you?

ES: I will show further developments at the Biosensors 2020 conference in Busan, Korea, as well as our work on surface- and tip-enhanced Raman spectroscopy at NFO16, Victoria, Canada. Group members will give invited talks on this particular topic at META 2020, Warsaw, Poland, and METANANO 2020, Tbilisi, Georgia.

MH: How do you spend your spare time?

ES: My free time is mostly consumed by career development initiatives for young scientists in Tomsk. It is a lovely university city in Siberia, where our lab is located, with huge intellectual potential. Right now we are working on an educational program for young scientists who are starting their own research group.

MH: Can you share one piece of career-related advice or wisdom with other early-career scientists?

ES: The hardest thing when developing your work further is accepting that at some point you cannot solve the complex questions you are interested in alone. And when you start building a group, it is a struggle keeping both the lab work organized and the research level where you want it to be. Build a good team, but first and foremost think about long-term solutions rather than one-time fixes. This is how you build momentum step by step.

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