Our research contributes to innovation in molecular electronics

You hold the record for writing the most articles among all Experientia Foundation scholars. What is the secret to your success? 

Most probably the collaboration. During my PhD studies, I worked at three universities – I spent the first year at University of Chemistry and Technology in Prague, then I studied at Masaryk University in Brno and at University of Fribourg, Switzerland. I have used contacts from all three institutions and the articles were the result of such collaborations. None of them is purely synthetic or theoretical, or purely physicochemical, it was always a combination of more disciplines. When you are lucky to work with brilliant scientists, you are simply more productive. Besides, following my stay in Switzerland I went to the United States for another post-doctoral research stay where I saw even better example of collaboration. 

In your research funded by the Experientia Foundation you focused on the design, synthesis and subsequently on defining the properties of stabilised graphene fragments. Why are they interesting? 

Graphene is a material with fantastic properties. The problem lies in the fact that, considering the size of molecules, it basically consists of an infinite two-dimensional lattice made of carbon atoms resembling a sheet of paper. Therefore it cannot be accurately and easily synthesised from small molecules in a laboratory. Yet, we can obtain graphene from a simple pencil. Graphite happens to be many graphene “molecules” stacked on one another like a pile of enormous number of sheets of paper. A pile of sheets of paper has different properties than a single sheet of paper. Similarly, properties of graphite are different from those of graphene. But graphene too is an electrical conductor and electronics would find it very useful if graphene could also be a semiconductor. Hence, scientists are trying to synthesise graphene fragments as small molecules (Figure 1A) to study them and understand what causes the specific graphene properties, so that they could modify them in an exact manner. In our research, we have focused on a triangular-shaped fragment, a polyaromatic hydrocarbon triangulene (Figure 1b). What is special about this fragment is that it has two unpaired electrons. This is a property that is very different from the vast majority of organic molecules that we know because their electrons are almost always paired. When you have unpaired electrons in a molecule, they can be arranged in a magnetic field for instance. Paired electrons in most organic molecules, on the other hand, do not interact with a magnetic field unless it is very strong. 

Figure 1: (a) A simplified graphene structure (two-dimensional lattice made of hexagons) with three simple graphene fragments highlighted in grey: anthracene (bottom left), phenanthrene (bottom middle) and phenalenyl (bottom right). The overall spin is shown as S: all electrons paired (S = 0), one unpaired electron (S = 1/2), or two unpaired electrons (S = 1). (b) Structure of the triangulene core (top) highlighted in purple with three substituents (R) and a 3-D model (bottom) with a “protective shell” of these substituents (grey), if R = triphenylmethyl. 

The main focus of the project was the preparation of a persistent triangulene derivative. How did you do it? 

The existence of unpaired electrons in molecules makes those molecules very reactive and, therefore, unstable. You cannot keep them in air, for instance. Oxygen is a very special molecule made of two atoms of oxygen which also has two unpaired electrons, which makes it a great exception among ordinary molecules. Because oxygen has unpaired electrons, it reacts very easily with triangulene which also has unpaired electrons. Therefore, we tried to design a method to prepare a precursor which would allow for the preparation of a kinetically persistent triangulene in a single step. 

Small organic molecules of this kind are promising candidates to lead to large innovations in electronic devices in the not-so-distant future. How will they help? 

Thanks to unpaired electrons, these molecules possess magnetic properties for instance. It means that if you put them together to create a material, you can create tiny magnets. You can direct the spins of unpaired electrons from one direction (state) to the opposite one. The advantage of a molecule as a magnet is that you can store one bit of information in it. We would then need just a small amount of material to store all knowledge, books, information and data produced by the mankind. Moreover, the spins of unpaired electrons can “feel” each other; this property is used for example in the research of quantum computing. 

In another joint project with Michal Juríček we worked with a specific molecular property other than the unpaired electrons: it is called chirality, an asymmetry in the spatial arrangement of atoms in a molecule. Owing to the chirality, two molecules made of the same atoms can have different conductivity of electrons with different spins. This is also used in a relatively young and highly promising field of molecular spin electronics (spintronics). 

Why have you personally specialised in this area of chemistry? 

I worked at several universities to complete my PhD and I learned different branches of chemistry at every one of them. But in all three positions I studied molecules that have unpaired electrons and are very reactive. I focused on the mechanisms of photochemical and pyrolytic reactions. Transforming one molecule to another in a photochemical reaction often does not happen directly. Short-lived reaction intermediates are formed during a molecular transformation; they only live for a nano- or even a picosecond. I have examined their structure and the possible ways to influence their reactivity or lifetime. When you have understood the transformation of one molecule into another, you can define the conditions of the reaction in order to create completely new, previously unachievable products. I found that very interesting. 

Thanks to the Experientia Foundation grant you could spend one year at University of Basel, Switzerland, working in the group of Professor Juríček. Why did you find his research appealing? 

I have known Michal Juríček for a long time; we come from the same town in Slovakia. We both participated in the Chemistry Olympiad at high school. Michal Juríček is an outstanding chemist. When he started his independent research I was sure that he would belong to the top chemists at least in Europe. In addition, the research he started doing was something I had been interested in for a long time and wanted to do myself. I knew that if I worked with him I would be conducting a high-quality research that I would really enjoy, and that I would adapt very fast to a new environment in his group. That is very important given the short time of the stay. 

What was it like to work with Dr Juríček? How does he work and what crucial things have you learned from him? 

Michal Juríček is absolutely brilliant when it comes to presenting his research outcomes and drafting grant applications. Last year, for instance, he was awarded an ERC starting grant for young scientists. Before that, he worked in the United Stated for two years in the group of Professor Stoddart, the 2016 Nobel Prize Chemistry winner. He has learned there how to write an excellent article, how to explain the importance of his research to the scientific community, and why his research should be supported. His experience and know-how have helped me immensely. I dare say that I have mastered my writing skills since then; I have written three grant applications of which two have been successful and I have to give him credit for that. 

What were your impressions of University of Basel? How is the Swiss scientific community different from the Czech one? 

One huge difference was the administrative assistance. Professor Juríček formed his own group in Basel and when I saw the quality of the administrative assistance provided by the university, I was astonished. He could devote all his time to research and work in the lab – not only working with students – he could actually spend most of the time in laboratory doing his research. And that is not common at all. Today, because I am in a similar position, I know it is only possible thanks to that administrative assistance. I have my grant and when I need to buy something for instance, I need not be distracted by asking “twenty” people to finish the purchasing. I simply use an application and order it. All the other paperwork is our secretary’s job. Administrative assistance at universities in Switzerland is simply great and it was perhaps even better in the United States. The Czech system still lags behind in this respect. Both in Prague and Brno, the group leader spends too much time doing administrative tasks that could otherwise be invested to students or doing research. 

What was your goal when you set off for your research stay? 

During my PhD studies, which I spent at three different universities, I did all kinds of things from synthesis to quantum chemical calculations. I was familiar with everything but I did not feel like an expert in any of these fields. And yet I spent more time doing calculations than the chemical synthesis itself during my PhD. I knew that I needed to get back to the lab, to gain confidence and to feel that I am also a good synthetic chemist. The research I did with Michal Juríček was exactly what I wanted: a combination of organic and physical chemistry of reactive intermediates, but the project itself required a lot of synthetic work above all. For me, it was a great motivation to utilize my previous knowledge of reactive intermediates, and gain extra confidence working among synthetic chemists. And I think I succeeded. I spent eight months in Basel and convinced myself that I can be pretty good at synthesis. I managed to prepare a molecule following an unexpectedly challenging route. 

The research stay also gave me time to think about what I wanted to do next. I applied for a grant at the Swiss National Science Foundation and received funding to leave for another post-doctoral research stay to Northwestern University in Chicago. In summary, my stay in Basel was very important for my career. 

After your stay in Chicago you returned to Basel and established your own research group. Will you tell us what is your group working on? 

We are trying to prepare efficient electron transport materials using organic molecules. Why do I think that it is important? Due to global warming we have to change the ways we generate energy that our entire society relies on. We need to switch to a way of generating electricity, which does not produce carbon dioxide emissions that speed up the global warming. There are solar cells that are based on inorganic technologies. These use primarily silicon that absorbs energy from sunlight and transforms it to electricity. Although we can produce these solar cells quite cheaply today, it still requires an enormous amount of energy. The lifespan of a silicon solar cell is about thirty years, but given the complexity of its production, it takes three to four years for this cell just to repay the energy invested in its production in the first place. In the next few decades, we need to change the way we produce energy, literally, on a massive scale, but we do not have so many sources of energy available to produce such a large number of silicon-based solar cells. It was clear that scientists must come up with a substitute for silicon solar cells. Organic molecules are a solution with an enormous potential. The newly developed syntheses make their production cheap, fast and without the need of such a large upfront investment of energy. As to their potency, they are still lagging behind. 

How will you create an organic solar panel? 

We are trying to use organic molecules to create a material absorbing visible light and, at the same time, able to “create” and direct a negative charge, i.e. electrons. The challenge is that molecules that make great conductors of electrons in photovoltaic cells are spherical while molecules that are great in absorbing visible light are typically planar. We are examining the question how to strike the right balance between properties of these two worlds to get hold of the best from both of them. Our hypothesis is that if we take planar molecules and arrange them in space such that they roughly resemble the shape of a sphere we can achieve synergies of molecular properties of both of these molecular worlds. 

How much time do you have for the project? 

This is a four-year project. In Basel, I received funding to form my own research group of doctoral students and I am writing grant applications to employ a post-doctoral researcher. I have four years to prove that I am capable of preparing these molecules and that they will have the expected properties. Consequently, I want to apply the outcomes of our research and create a solar cell. 

Can you tell us in conclusion what the Experientia Foundation grant has meant for you personally and what progress you have made in your career, and also as a person, thanks to your research stay? 

Personally, I found the entire story of the Experientia Foundation and all people who support it very interesting and inspiring. They invest their own money to help others grow, and I think it is a fantastic idea. I studied at a high school in Prievidza where we had an amazing chemistry teacher, Miroslav Kozák, who managed to foster a great number of students to reach the International Chemistry Olympiad. All of us, his students, still meet him every year. This is how a community of dozens of young people was formed (I am one of the older ones). We know that certain things may be difficult for some of his students because everyone comes from a different social background. So we, the ones who can already afford to invest some money in the development of other people, decided to get together and founded a non-profit organisation called Prievidza Chemical Society. We are gradually starting to support young gifted chemists from high schools in Slovakia. We have existed for two years now and we are finding out step by step how we can help and where else we would like to contribute. The Experientia Foundation has inspired us a lot. So, for me personally, it has been important yet from another perspective than just doing my research abroad. This experience has been equally important for me. 

Is there any message that you would like to give to prospective applicants for the Experientia Foundation grant? 

When I look back at the time I spent doing my post-doctoral research abroad, I am surprised how fast the time went by. You move abroad, start a new project and it takes some time to adapt to the new environment and colleagues. Even before the end of the stay you have to think what to do next and apply for other grants if you want to stay in academia. At the same time, you must be as productive as possible in today’s science. Given the duration of the stay it may turn to be quite a demanding and stressing period in your career. Today I know that I was not completely ready for it and that I should have asked my older colleagues during my PhD more questions about their post-doctoral experience. In order to be better equipped to cope with all those changes. So, please ask questions. You can ask me, too, I will be glad to help. 

Also think about whether you want to go abroad on a post-doctoral research stay just once or twice to look around in more laboratories. If just once, talk to your future supervisor about the possibilities of extra research funding so that you could stay a year longer, for instance, after your Experientia Foundation grant is over. Because one year is a very short time. I wish you good luck in your choice and a lot of success in your career.