Kyoto Prize winner Hiroo Inokuchi is one of organic chemistry's lifelong stalwarts and innovators. His work led to the development of organic light-emitting diodes, or OLEDs, which power ultrabright monitors. His notion of organic superconductors may well define the future of electronic gadgets and energy research.
At 80, Inokuchi is spry and good-humored with an easy laugh. While he's not a figure in the public eye, much of organic chemistry refers back to Inokuchi's 60-year body of work with carbon, that very common element in pencils and sugar and nearly everything around us.
The Kyoto Prize's foundation awards three prizes each year, (worth 50 million yen each, or $500,000) for advances in science, culture and human spirit.
While many scientists were finding ways to exploit metals and inorganics to conduct electricity, Inokuchi toiled away at figuring out the carbon molecule. He's learned how to use it to conduct electricity and to store energy, using the thinnest of films, like the 3-mm film used for the bright little OLED televisions -- though he doesn't have one yet because they're always sold out when he goes to buy one.
Wired: How did you become fascinated with carbon, while the world rushed to silicon?
Hiroo Inokuchi: My background is not electrical engineering or anything to do with electromagnetic study. My background is colloidal chemistry and carbon is a very basic particle.
Carbon has many many applications. Carbon's biggest application is graphite, what we call carbon black. For example, a tire for a car or airplane has huge amounts of carbon. If we took out the carbon they would get very hot and explode because the carbon absorbs heat and dissipates it. If it did not, the airplane would explode. It is one of the properties that makes carbon very unique. So if it absorbs heat, then why does it happen?
You start with the particle, which is a point, one-dimensional. If you stretch the particle, you get a fiber -- that is two dimensions. If you weave the fiber, you get the film. The three dimensions actually come back to the particle.
Wired: How did understanding the carbon molecule lead to connecting organic materials and electronics?
Inokuchi: Sixty years ago when I started studying carbon, there was very little data and few applications. What was known at the time was the structure of the molecule. You can get all the way down to just a few molecules of carbon and you find electrons that move freely.
The range for the carbon molecule is from graphite to benzene. These materials have several shared properties, and my belief that they must share more properties and with other materials made me look at properties of materials within the family of this material. This is a chemist's thinking.
I did not start studying for electrical materials. I started out thinking about the properties of a material and knowing that it conducted heat and began looking for materials in the family that also conducted heat and electricity.
Wired: Why is your work considered a breakthrough?
Inokuchi: What we have accomplished is to make scientists and inventors realize that the taboo for conducting electricity through carbon is broken.
Coming from breaking the barrier to looking at organic materials to conduct electricity, the next step then is to ask can we use that for other applications? The phenomenon of a catalyst is interesting because things become a catalyst because of the internal working of the particle.
So when you look at it linearly, the immediate thought is can you use this as a semiconductor. But the second thought, one we are starting to explore, is if this can conduct electricity, can it be used as a catalyst.
I have been working on this for 30 years but have yet to gather enough evidence to produce a scientific paper on it. But I will if there is one to be produced. I dedicated my life to working on this and I am not done yet.
Wired: What are the most promising areas for future applications, beyond the ultrathin screens in cellphones and televisions?
Inokuchi: In my mind the most promising area is energy conversion, for fuel cells and photovoltaic uses. As Sony has proved, the advantage of using organic material is it's very easy to make very thin film that conducts electricity. We should be able to make a thin film that collects energy.
From the scientist point of view, God and the sun give us all the energy we need but we have to collect it. This application could be very important to ending the human habit of digging up and using our reserves of petroleum and coal that should be saved for something important.
Wired: Why would this be a better material in photovoltaic panels than silicon?
Inokuchi: With metal you have to break up the molecules. But with organic materials the electrons are moving freely around the matter so you don't have to break it up. You can make a very thin film using a chemical vapor at a lower temperature and much easier than other materials, and it doesn't alter the properties of the material. You can use polymer to hold it in place because the vapor will stay. So you can just paint or print this carbon-based matter. You can print a solar cell on your back or on a piece of paper. And it remains flexible.
You paint this very thinly at very low temperatures. Carbon does not oxidize to become rusty or dirty. This is why Oriental artworks and those done with graphite do not need restoration. Carbon breaks down to carbon monoxide or carbon dioxide, both gases. At room temperature this is a very slow process.
And the materials are very common. We can make more energy-gathering cells, we can make them cheaper than the current technology. The shortcoming of organic materials compared to metal is that the temperature at which it disintegrates is also very low.
In Japan we have a saying that the heavens give us only one gift. Heaven does not give you two gifts.
Wired: It's quite an honor to serve on the Japan Space Program. What do you find most interesting there?
Inokuchi: It's true that I oversee the experiments conducted there. But I am a man of basic science. In space, I am interested in what happens to surfaces and material in the absence of gravity. The most interesting phenomena are in liquids, not limited to organics. Without gravity, everything happens at the surface. In the absence of gravity, you can take a ball of water and make it hollow. Then you inject smaller amounts of water into it and it forms three separate balls within the hollow. This is a function of surface tension.
Wired: So many discoveries that lead to good can also be used for evil. Is this one of them?
Inokuchi: So far, only good uses are thought of. It's unlikely it could make devastating weapons. It's a very stable element. But some organics can be harmful. Like all ideas, we have to be careful.
