Interviews with Retiring Tokyo Tech Professors, Spring 2015

Thirty professors engaged in teaching, research and administration over the years are retiring at the end of the 2014 academic year in March 2015. We were lucky to catch up with two of them before they leave the Institute. They shared their memories and plans for the future.

My research on solar cells began on 1972, when I was in the first year of my master's program. At the time, I was studying transistors in semiconductors; but Professor Kiyoshi Takahashi, who was my academic supervisor, told me that the age of the solar cells was coming and that I should catch the wave. He had great foresight, and the idea captivated my imagination, so I took his advice. That's how I got started.

I expect solar cells to become the core energy of the nation around 2040 to 2050, which means we still have 30 or 40 years ahead of us. Considered from this point of view and assuming the goal of full-scale application, we have just passed the midway point.

The development of solar cells in our generation was rather focused on how to make more efficient products at a lower cost. In the next phase we'll need to create systems and use solar cells as a core energy source capable of bearing 10 to 20 percent of Japan's electricity; and this is just about to begin.

I believe in the combination of various energy sources; but considering issues such as pollution and the depletion of resources, it is obviously crucial for the future that Japan gradually shift from petroleum and nuclear power to natural energy.

The largest problem facing solar cells has been cost. No matter how efficient they are, you'd be reluctant to install rooftop panels if they were prohibitively expensive, wouldn't you? The solution I am thinking of is low concentration photovoltaics (LCPV). There are some variations, but the basic idea is to focus a ten-fold concentration of sunlight on a certain spot and convert the energy to electricity. In a system aiming for a concentration ratio somewhere in the neighborhood of 1000 times, you would need to track the sun precisely, which means utilizing dual axis trackers to deal with Japan's cloudy climate. For LCPVs, however, single axis trackers would suffice. So, my next project will be LCPV.

If possible, I would like to live to see the world of 2050, where I believe that solar cells capable of producing 10 to 20 terawatts of energy will be a reality. Should I somehow manage to, I would be more than 100 years old [laughs].

I am eager to support the development of environmental energy as much as I can. I don't think it's time for me to rest just yet.

My main area of expertise is geology, and I've been involved in a wide variety of research on the history of the earth and life. My first subject of research was the geology of the Japanese Archipelago, and I spent almost 20 years completing it. Focusing on a hypothesis about the formation process of the Japanese Archipelago, I devoted myself to conducting high-pressure experiments to reproduce materials that may be present in deep Earth at University of Toyama and Stanford University. Then, about 20 years ago, I moved to Tokyo Tech. Although I continued with this work, I also started joint research with around 50 to 60 institutes from 30 countries. I collected a variety of samples from around the world to elucidate the history of the Earth and life.

My style of research is to take a "bird's-eye view" of science. It is like overlooking the entire plain from above. The majority of researchers specialize in their own fields of expertise, but they cannot compete with experts from other fields when discussing a wide variety of topics. I saw some people trying to expand their horizons, but it seemed difficult for them to become competitive in fields outside of their own areas. Their knowledge tended to remain wide but shallow. I strived personally to study other fields to gain deep and broad knowledge beyond geology. Well, it was easier said than done [laughs].

Let me briefly explain how I mastered other fields. Taking biology, for example, there are 6,000 organic molecules. The key is not to memorize the name of each and every one of them, but to learn the most important key words. That is the first way to learn. The second way is to become friends with specialists in each field. Ask them to be your tutors, and study the basics of their fields thoroughly. By these methods, which I call "self-education" and "private tutoring," I obtained wide and deep knowledge in more than 50 different fields to discuss topics with various experts, sometimes engaging in fierce debate.

I will retire as a member of the faculty, but I am planning to continue summarizing my studies. I have also received an offer to participate in an asteroid component analysis project related to planetary formation theory of the solar system. I'm also still making other plans for the future.

To the students, I would like all of you to have a sincere persistence in your studies and research. Real understanding requires far more than what you do when you are reading a newspaper. If you find a single item that you don't understand, you need to search through the literature and struggle. If you get absorbed in the struggle for understanding, you will feel a sense of accomplishment when you finally understand things, which is an experience of a lifetime. There are students who are seriously studying and willing to contribute to the world, however, regrettably there are also more and more students who misunderstand this point. I hope they will soon realize what I mean and find their own true purpose in life.

Published: March 2015