Evgeniya Sheremet, professor of the TPU Research School of High-Energy Physics, became one of the first participants of a new project of Materials Horizons (Q1, IF 14.356) dedicated to young scientists. It is one of the most prestigious international journals in materials science.
The Materials Horizons recently launched a column with interviews of promising young researchers. The editors are very demanding to the candidates selected to participate in the project.
Evgeniya was asked to take part in the interview after her publication on a method of producing high-quality graphene for flexible electronics. She and her colleagues from two TPU research schools and foreign research centers succeeded for the first time in modifying graphene combining functionalization with diazonium salts and laser processing. As a result, they obtained a high-quality material with properties necessary for flexible electronics. This article was highly praised by the editorial board and became a cover story of the issue.
Full text of the interview.
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?
My research work started in developing surface- and tip-enhanced Raman spectroscopy for nanomaterial analysis, including carbon nanotubes and quantum dots. Shortly 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 and making the material a semi-transparent dielectric. When the laser illuminates the sample, these functional groups get removed and the C=C bonds become 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 Ph.D. students had the 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 the laser reduction and discovered that the interface gets 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 in GO with its oxygen-containing groups, 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 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 in our general vision for biocompatible electronics that should fulfill all those requirements but also prove to be non-toxic and mechanically flexible.
Photo: winners of the competition, E. Sheremet - fourth from left (L'Oreal press office)
What aspect of your work are you most excited about at the moment?
Now we are looking at the fact that the laser processing we report in our work induces also a composite formation with the polymer material used as a substrate, and that the process turned out to be universal. This opens a range of exciting possibilities when using different conductive materials and substrate polymers for flexible electronics applications. The process is also scalable and we are certain that there are plenty of applications that will emerge from it.
In your opinion, what are the most important questions to be asked/answered in this field of research?
For us, it is most important to realize the finest control of the material properties possible and test the limits of the technology 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 lie the applicability limits, can we develop competitive biocompatible materials, antennas, and wearables?
What do you find most challenging about your research?
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 the time and resources are limited.
In which upcoming conferences or events may our readers meet you?
I will show further developments at Biosensors 2020 conference in Busan, Korea, as well as our work on the surface- and tip-enhanced Raman spectroscopy at NFO16, Victoria, Canada. The group members talking and invited talks on this particular topic will participate in META 2020, Warsaw, Poland, and METANANO 2020, Tbilisi, Georgia.
How do you spend your spare time?
My free time is mostly consumed by the initiatives of career development 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.
Can you share one piece of career-related advice or wisdom with other early-career scientists?
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.
This article was published in the Royal Society of Chemistry’s peer-reviewed journal, Materials Horizons.
Evgeniya Sheremet is one of the founders and leaders of the TERS research team at TPU. The group is working on carbon and plasmon nanomaterials, their applications in biomedicine and flexible electronics as well as on modern methods of nanoscale analysis.
In 2017, Evgeniya received the Prize of the Tomsk Region for scientific contribution to experimental physics and in 2019 the L'Oréal-UNESCO For Women in Science Awards.