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Researcher interview #04 | Prof. KERA, Satoshi

July 2020 (1 | 2 ≫next

Discourse on Curiosity ―Learning from the world, a dream in your mind, a journey to its end―

In this interview, I will be talking to Professor Satoshi Kera in the Department of Photo-Molecular Science. Prof. Kera's research focuses on organic materials with special functions, such as organic semiconductors. Because of their superior properties compared to conventional inorganic materials, functional organic molecular materials are expected to have advantages in many applications. However, actually applying them, in semiconductors as an example, has been difficult because we still do not understand the mysteries behind their unique functions. In order to unravel these mysteries, Prof. Kera is investigating the electronic states of the molecules that make up functional organic molecular materials by using state-of-the-art analytical techniques and is aiming at establishing guidelines for materials development.

Click here for Prof. Kera's profile.


The road to becoming a researcher

Please tell me why you became a researcher.

I don't remember for sure, but when I was in elementary school, my friends used to tell me, "You're going to be a scientist." I guess that was the impression I gave off. I like the stars, so my father and I often went to the mountains and the sea to take pictures of them. I remember telling my father that I wanted to be an astronomer, but he told me not to do it because it would not be profitable. My family had a business, so they had a very strict sense of money. I was interested in being a scholar or a doctor of science from then on, but I didn't directly encounter research until I entered university.

What do you think you would be doing if you were not a researcher?

I enjoy research so much that I haven't really thought about other careers. However, I could never have become an office worker. If I were to quit my job as a researcher, I would probably start my own business and be involved in commerce. I feel like I have the blood of a salesman in my veins. When I go abroad and find some interesting product, I think, "Oh, this could be a best seller in Japan." I have also thought it would be interesting to become an architect and run a design office to create dream houses for clients. I really like designing things, so I get a lot of enjoyment out of designing the vacuum chambers I use in my experiments. Since I was a student, I have designed a lot of equipment using CAD (Computer Assisted Design) software.

I sometimes hear from researchers that they want to be independent and run their own business instead of becoming a member of a big company, which many other people are eager to work for.

Oh, we have that in common, don't we? A pioneering spirit is important for a researcher. I think people who innately have such a spirit often become researchers. I think it's almost a necessity.

Guided by my mentors and nature

You said that you liked the stars, but how did you finally select your research field?

Choosing a university was a turning point for me. At that time, I was interested in the field of materials science for artificial organs. Chiba University had just established the Department of Functional Materials Engineering, which sounded new at the time. I was attracted to it and thus entered Chiba University. In my third year at Chiba University, I needed to select a research laboratory I would be assigned to. At that time, I met Prof. Nobuo Ueno, who had a very strong personality which made me want to do research with him. So I ended up joining the Ueno Lab. This was my first encounter with my current research field.

So, did you choose your lab because you were attracted to the professor's character?

Yes, I did. Prof. Ueno and Prof. Yoshiya Harada, two very unique people, had established the lab. Even at that time, its main research topic was functional organic molecules. So, I have been doing research on the same topic for about 25 years, continuing since I was a student. I think this is a bit of an unusual case. Generally speaking, students need to change their labs after they get their master's or doctor's degrees, meaning their research topic will change as well. I myself tell my students so. But in my case, I've continued to study the same thing.


Why was the situation different for you?

The field of natural science is broad, so it is important to experience looking at things from different perspectives. In general, I think it is the right strategy to move from one lab to another. On the other hand, there must be a destination you can finally reach by pursuing a specific specialty. I am moving in such a direction. Thanks to this focus, I believe that there is a world that only I can see. I think it may be a bit presumptuous to say nature led me here, though.

What are the keywords we would associate with your research to try to understand it? For example, are they "photoelectron spectroscopy" and "functional organic molecules at surfaces?"

I wouldn't say focusing on keywords is the best way to get a feel for my research. I like to say, "We shed light on the electrons in a molecule," or more simply, "We try to understand the 'feelings' of the electrons in molecules." The keywords you mentioned are related to how we do this. Photoelectron spectroscopy is just a method to see electronic states. Since it's basically a tool for observation, I'll change my method if there is a better one. Because of this, developing novel and more appropriate equipment to observe electrons better than before is important for our research. About the second phrase you mentioned, we put functional organic molecules at the surface of solids to observe them. This is also just a method for looking at the molecules, so we could use something else.

Shedding light on an electron in a molecule

I can imagine the shapes of molecules and how molecules are assembled to form a crystal. But when it comes to the electrons inside the molecules, I find it difficult to visualize. Could you please explain to someone who is educated but not specialized in natural science the significance and the charm of shedding light on the "feelings of electrons in molecules?"

Umm, that's difficult. Well, imagine water in a glass bottle. The bottle corresponds to a molecule, and the water corresponds to the electrons within it. In molecular materials, it's like there are many bottles filled with water that have been lined up. For this molecular material to conduct electricity, the water in one bottle must move to the next bottle in order, right? If the bottles are lined up tightly, the neighboring bottles, that is, the neighboring molecules, are touching each other. In this case, do you think the electrons in the molecules can touch each other and move to the next molecule?

Let me see, the walls of the bottles touch each other, but the electrons are blocked by the walls and cannot move to the neighboring molecules. In other words, electricity cannot flow.

That's right. Next, let's consider the case where they are not molecules. Take silicon, for example. It is a "semiconductor" used in computer parts, and electricity can flow through it. Silicon is a hard crystal in which atoms are bonded together by a very strong force. Some of the electrons in the crystal are naturally ejected from their original atoms by thermal energy when at room temperature. For the ejected electrons, the entire material is like one big container, so they are not blocked by walls and can move freely. In this way, electricity can flow, OK?

You can see that the situation is very different between this case and the case of the molecular materials. Furthermore, molecules are soft, squishy, and have no firm shape. In order to understand the flow of electricity, it is necessary to describe the dynamic aspects of electrons, but since the shape of the molecule changes from time to time, we need to consider the movement of electrons and the change in the shape of the molecule at the same time. In a material made up of loosely connected, squishy bottles, we need to find out how electrons flow and pass through the walls by understanding the feelings of the electrons in the molecules.

Ah, it's really complicated. When you say "dynamic," do you mean that when the electrons move, the molecules also move along with them?

Yes. So, we need to think about the motion of both the electrons and molecules at the same time. Conventional molecular science has been developed through studies of gaseous samples based on single molecular dynamics. Here, the motion of atoms (nuclei) and the motion of electrons do not affect each other, so we can separate the motion of each. However, solids can't really be understood within that framework. Because of our current level of understanding, if we want to create a physical "something," we don't have a strategy for how to design the molecules that make it up. To achieve this, I think we need to establish an understanding of the "feelings of electrons" in molecular solids. That's my work.

Essentially, if basic science can provide guidelines for molecular design to industry, it will fundamentally change materials development?

Basic research is important. But it is very difficult to answer that question, "What is basic research for?" I think it is our duty as researchers to look at application possibilities. Even if you don't know what a patented discovery is useful for at present, one day the world may suddenly change, and it may become an indispensable tool. That's why we have to discover as much as possible. I believe that I am playing a part in this. As a researcher, I think it is very important to accumulate knowledge for humanity and to provide tools for the future.

A message to would-be researchers

Would you please give a message to students who are aiming to become researchers or to major in sciences, although I think I've already gotten some ideas from what you've talked about already?

Various elements are necessary for expanding the knowledge of mankind, so diversity is important. Therefore, it is not good to do the same thing as everyone else. Of course, joint research is important, but don't be just another ant swarming for sugar. Originality is essential, and for that you need to have a broad perspective. Research and development in Japan is prone to evolve according to the Galapagos syndrome, as is often the case with Japanese products, for better or worse. You will not be aware of this if your experiences are limited to Japan. So, I recommend that students work abroad for a few years and see Japan from the outside. By living and studying in a completely different culture, I want them to learn different methodologies and different ways of thinking.

You've studied in Germany before, haven't you? Did your experience in Germany have a significant impact on you?

Yes, indeed. In today's world, Germany is one of the few developed countries that continue basic research. Although I was there only for one year, the experience is invaluable to me. Two things are particularly important to me.

The first thing is that I met my mentor there; he taught me how to think as a researcher. In Germany, I was supervised by Prof. Eberhard Umbach. He is a leading scientist in physics there. One day, when I was giving a presentation on the results of my experiments for the month, Prof. Umbach suddenly had a serious look on his face. He said to me, "I'm going to be a devil now and teach you how to do things in the German way." It's true that his instruction was strict. But Prof. Ueno, my supervisor in Japan, was also a strict person, so I thought, "Well, it's pretty similar." I have two "fathers," one in Japan and one in Germany, who have helped me a lot. I lost my father when I was in university, so unfortunately, I never had a chance to share a drink with him. I personally consider Prof. Ueno both my mentor and a father figure.

The second thing is all the friends I made. The people I met in Germany, students and young researchers at that time, have since grown into experienced researchers. Even now they help me with joint research and other things. Nowadays, because research fields are becoming more and more fragmented, it is impossible to reach our goals alone.

Is it difficult to conduct joint research with someone you have never met before?

If it's necessary, it's possible, of course, to conduct joint research even if we don't know each other at all. However, since we're all human beings, it's fun to collaborate with people we get along with. Our work goes well because a relationship of trust has been established.

In short, my message to prospective students is, "Enjoy research!" If they don't enjoy doing it, they will not be successful. They should want to do it, and they should be self-motivated. Students often ask me for advice when they don't know which experiment to do. I tell them, "If you don't know, try something; the results will tell you what the next step is."

Thank you very much for your message.

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