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Feature Story | Argonne National Laboratory

Meet Dieter Gruen, renowned scientist and innovator

Manhattan Project veteran, internationally recognized innovator, fierce advocate for climate action.

Dieter M. Gruen is a 99-year-old scientist who fled Nazi Germany, worked on the atomic bomb and continues to push the bounds of alternative energy technology. 

Throughout his exceptionally long and distinguished career, Gruen has made important contributions to new energy technologies. He worked on the Manhattan Project and spent more than 60 years of his career at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, where he worked on the first nuclear submarine designed by Admiral Rickover, solved problems related to nuclear power and created new materials (including a new kind of diamond). Gruen now devotes his life to fighting climate change by making pivotal advances in solar energy technology. 

It’s been a wonderful life that I have been able to spend doing science — that’s what I like to do — and I’m still at it. I do hope that I have been able to make a contribution in my life to make other people’s lives a little better.” — Dieter M. Gruen 

Gruen has a remarkable life story. Born in 1922 and raised in Germany, he immigrated to the United States on his own when he was only 14 years old. When he could no longer attend school in Nazi Germany, his family arranged for him to live with an uncle in Little Rock, Arkansas. Fortunately, he reunited with his parents in Chicago a few years later and went on to receive B.S. and M.S. degrees from Northwestern University in chemistry, and eventually a Ph.D. in chemical physics from the University of Chicago.  

Shortly after graduating from Northwestern, Gruen began working on the Manhattan Project, the U.S. government’s top-secret effort to develop the atomic bomb. At Oak Ridge, he worked on the large-scale electromagnetic separation of uranium-235. The nuclear material he helped to produce would be fashioned into the bomb that fell on Hiroshima. 

After the war, Gruen helped form Oak Ridge Scientists and Engineers, a group dedicated to ensuring nuclear weapons were never used again in war. Then, Gruen returned home to Chicago and began working at Argonne only a year after the establishment of the DOE national laboratories, at a time when Argonne was becoming the national center for the development of nuclear reactors. His work at Argonne concerned scientific problems relevant to nuclear power and led to his being asked to serve as a delegate to the Second United Nations Conference on Peaceful Uses of Atomic Energy in 1958.  

I have loved this country from the moment I sailed past the Statue of Liberty and set foot on its shores,” said Gruen. It’s been a wonderful life that I have been able to spend doing science — that’s what I like to do — and I’m still at it. I do hope that I have been able to make a contribution in my life to make other people’s lives a little better.”  

In 2021, U.S. Rep. Sean Casten (D-IL) nominated Gruen for the Presidential Medal of Freedom — the nation’s highest civilian honor — for his exceptional contributions to materials science, innovations in alternative energy and advancement of the national security interests of the United States. 

Dr. Gruen is a renowned scientist and fierce advocate for climate action whose contributions over eight decades have transformed American technological development, from nuclear fission and fusion to solar and energy storage. We as a nation are forever in his debt,” said Casten. 

An internationally respected innovator, Gruen’s work at Argonne focused on alternative energy, but crossed into a wide variety of disciplines, including chemistry, physics, nanotechnology and materials science. In his work at Argonne, Gruen designed a solar-powered heat pump, was a pioneer in the chemistry of molten salts, the ultra-sensitive detection of sputtered atoms using a technique called laser ionization mass spectroscopy and the establishment of the electronic structure of neptunium — a radioactive metal. He also synthesized ultrananocrystalline diamond films, creating a new type of diamond that is very smooth, hard and virtually frictionless. Gruen served for 15 years as the associate director of the Argonne Materials Science division with responsibility for the materials chemistry program. For this work, he received the University of Chicago Award for Distinguished Performance at Argonne.  

My work at Argonne was strongly influenced by my experiences on the Manhattan Project. On reflecting back on what I did during most of my life, I would have to say that my scientific work had its origins in the realization that nuclear power was something really new and important, that there were two sides to it: one destructive and the other constructive, and that that power could be used as a nonpolluting alternative source energy. So, for the rest of my scientific life, I devoted myself to the solution of this very daunting and challenging problem of how to create a sustainable, nonpolluting global energy source.” 

Throughout his career, Gruen consistently addressed problems in alternative energy, including fission, fusion and solar energy — which he now believes is a viable path forward to achieving a sustainable energy future. The sun could become our global energy source,” he says. We just have to learn how to use it efficiently.” 

Although he officially retired from Argonne in 2012, Gruen never stopped working. He continues to make solar power more efficient and less expensive. His work on alternative energy is focused on developing a graphene solar cell with the potential of reaching a high light-to-electricity conversion efficiency. The experimental work on a prototype solar cell was done by Gruen under a research contract at the University of Illinois at Chicago and has the potential to make solar power competitive with electricity generated by fossil fuels. 

I count every day I’m able to do this,” Gruen said. It won’t last forever, but I’ll do it as long as I can.” 

Over the course of his distinguished career, Gruen has published over 400 peer reviewed publications, mentored hundreds of students and received dozens of awards for his research and innovations, including the prestigious MRS Medal from the Materials Research Society for his creation of ultrananocrystalline diamond film. He holds over 60 patents, many of which have been licensed and are in use today. His work to develop an ultraviolet excimer laser has been used to remove arterial occlusions that cause heart disease, and his nanodiamond film led to the founding of a company to commercialize its use, for example, in rotating shaft seals and in electrodes for artificial retinas. 

Gruen lives in the Chicago suburb of Downers Grove, in the house he shared with his late wife Dolores, a psychologist who received her Ph.D. from the University of Chicago. They were married for more than 66 years and have three children, nine grandchildren and two great-grandchildren. 

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The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://​ener​gy​.gov/​s​c​ience.