Karl Wolfgang Böer papers

Biographical and Historical Notes

"After retiring from all official duties at the university, I feel it to be my obligation to devote all my efforts, together with my former students, colleagues and friends, to build on the foundation we created, and extend our influence to a much broader world in making the change from the fossil to a solar world a reality." - Karl Wolfgang Böer, 2014

Physicist, inventor, university professor, and solar energy pioneer Karl Wolfgang Böer was born March 23, 1926, in Berlin, Germany. He became a naturalized American citizen in August 1972. Böer was educated at Humboldt University in Berlin (Diploma, Physics, 1949; Doctorate, Physics, 1952, Dr.rer.nat.habil. State Physics, 1955), where he also taught in Physics from 1950-1958. At Humboldt University, also taught in the II Physics Department and from 1958 to 1961 in his own IV Physics Department. Böer formed and directed a research team, which became a section of the II Physics Department in 1951 with eight scientists. In 1958, Humbolt University created the IV Physics Department for him, which he directed until 1961, when the group had grown to 26 scientists and 23 support personnel.

Upon completion of his doctoral degrees, and in addition to his academic position at Humboldt, Böer founded and became director of the Section of Dielectric Breakdown of the German Academy of Science in Berlin. The laboratories included facilities to grow and analyze cadmium sulfide (CdS) single crystals, optical and electrical laboratories, a magnetic laboratory (40kG/8cm-3), a high pressure facility (20kbar with optical windows), and x-ray, emission spectroscopy, and high vacuum and low temperature facilities. The shops included mechanical (for metal and wood), glass, and electronic shops.

Böer's decision to immigrate to the United States was prompted by the construction of the Berlin Wall, an event that took place while Böer was attending an international scientific conference at Cornell University. Two weeks later he received an invitation to New York University for a guest professorship at the Physics Department and began thereafter his career at the University of Delaware. Böer began his career at the University of Delaware as an associate professor of physics in 1962. In 1965 he became professor of physics; in 1971, professor of physics and engineering; and in 1993, distinguished professor of physics and solar energy.

With a vision of solar energy as a supply source for residential energy and a means to reduce American dependence on foreign oil imports, Böer anticipated issues of the energy crisis of the mid-1970s and founded the Institute of Energy Conservation (IEC) at the University of Delaware in 1972. He served as its director and chief scientist from 1972-1975. Under Böer's direction, the IEC grew from a small research and development group into an internationally renowned research facility named by the U.S. Department of Energy as one of only two Research and Educational Institutes of Excellence in the United States. IEC was an important training ground for many of the individuals who have contributed to advances in photovoltaic technology for delivery of solar energy. In the introduction to a special issue of Progress in Photovoltaics celebrating IEC's 25th anniversary in 1997, Birkmire and Hegedus credited Böer with recognizing the potential of thin film photovoltaic cells coupled in hybrid configuration with thermal collectors to also reduce the solar cell temperature and thereby its collection efficiency. This was a clean and inexpensive means to deliver solar energy. Böer obtained funding from the National Science Foundation, electric power utilities, and the University of Delaware Board of Trustees to establish the IEC. This pioneering endeavor predated the first oil embargo, as well as the establishment of the U.S. Department of Energy and the Solar Energy Research Institute (SERI), both formed in 1977.

Research during the early years at IEC focused on increasing the conversion and delivery efficiency of copper sulfide/cadmium sulfide(Cu2S/CdS)used in thin film solar cells. In 1972, Böer and a team of experts proposed Solar One, the first solar house, to harvest solar energy in a total system approach. The proposal was developed with a team of experts, including Professor Maria Telkes, formerly of MIT, Kudrel Seluck from the University of Minnesota, several of his students and architects. The experimental house, with solar-generated heat and electricity, was built in 1973 at the University of Delaware with support from Delmarva Power and Light Company.

The Solar One House of the University of Delaware was the first systems hybrid house in the world to convert sunlight into electricity and heat through the same solar panels that are incorporated into the roof structure and not deployed on top. The heat is extracted through air-ducts and conducted into the basement where it is stored as heat of fusion in sodium sulfate decahydrate-eutectic (melting at 125o F) filled cylinders and conducting to the rooms for heating in the winter. During clear summer nights the radiation coolness from the roof panels is also conducted into another eutectic salt (melting at 60o F) bin in the basement for cooling the rooms in the summer. The center Window of the living area had a Thrombe wall as a concrete block behind the window to store heat in the winter and distribute it evenly through the adjacent living space. All heat ducts were controlled electronically by louvers from a central control panel with inputs of time, outside and room temperature. The refrigerator in the kitchen had an air-duct to the roof to vent the hot air out from behind to the roof in the summer. A separate battery storage bin was built aside of the house for load leveling of the harvested electric energy, a feature that was decades ahead of its time. The Solar One house was designed using state-of-the-art passive house features, such as super-insulation of outside walls and ceilings; all essential windows were pointing south; the south windows had a proper overhang to protect from direct summer sunshine entry. The house was immediately recognized by the world press as a pioneering breakthrough for solar energy utilization and was open to visitors with more than 100,000 in the first year. It was featured in most of the international science and technical journals and listed as historical building by the US Department of Energy.

Parallel to development of IEC, Böer was involved in creating Solar Energy Systems (SES), Inc., a private company and subsidiary of Shell Oil Company, in contract with the University of Delaware and IEC. Böer served initially as chairman of the board (1972-1981) and chief executive officer (1972-1975); he later served as chief scientist (1975-1985). The purpose of the company was to produce solar energy conversion hardware, beginning with Cu2S/CdS solar cells capable for mass fabrication. By 1985, SES, Inc. had a total of 450 employees of which were 34 research scientists, with a complete instrumented research and analysis laboratory including SIMS, SAM, several electron microscopes for transmission and surface visualization, ultra-vacuum equipment for epitaxial growth, micro-chemical laboratories for analytical and synthetic research. SES also had semi-automatic production equipment for three-shift solar panel production with an 120 sqft Vacuum chamber with pre-vacuum entry and exit chambers to permit semi-continuous vacuum deposition.

In 1975, Böer returned to a fulltime research and teaching position and began advising the University's president on long term projects. In 1993 he was named Distinguished Professor of Physics and Solar Energy. He eventually retired from the University of Delaware in 1994 as Distinguished Professor Emeritus of Physics and Solar Energy after receiving many awards for teaching and research. In 1998, the University presented Böer with its Medal of Distinction. In 2012, he received the doctor honoris causa degree from the Technical University Berlin.

Böer's expertise in solar cells, solary energy systems, solid state physics, and electronic transport in solids is internationally recognized. He holds 28 patents in solid state technology, authored over 350 articles on solid state physics and engineering, and on solar energy conversion. He is the author of seven books, His Survey of semiconductor Physiscs's first volume is treasured as the "Bible of semiconductor physics" and praised by Van Nostrand Reinhold editors as the most comprehensive book of the field ever written by a single author. With over 3,900 pages in two volumes, the third edition is titled Handbook of Semiconductor Physics, co-authored with Professor Udo Pohl, Technical University Berlin. Other books are the Handbook of Thin-Film Solar Cells, Introduction into Space Charge Effects in Semiconductors, and Field- and Current inhomogeneities in semiconductors, all from Springer Verlag, Berlin. Böer has edited or co-edited twelve additional books or conference proceedings. Böer was the founding editor of physica status solidi: the International Journal of Solid State Physics, and edited Solar News and Views in Solar Age, the Journal of Solar Energy Materials, and the editor-in-chief and founder of Advances in Solar Energy. He has received the highest honors of his profession, including election as a fellow of the American Physical Society (1965), fellow of the American Solar Energy Society (ASES, 2000), fellow of the Institute of Electric and Electronic Engineers (IEEE, 2001), and fellow of AAAS (2012).

Throughout his career with the University of Delaware's physics and engineering departments and the IEC, Böer worked on many projects relating to the research of the defect structure of CdS single crystals and the optical and photoelectric properties. He concentrated his main interest on further investigation of high-field domains (now called Böer domains) which he discovered with his team in Berlin before emigrating to the United States. In America, he developed methods for using such domains to unambiguously measure electron density and electron mobilities as a function of high electric fields and discovering the dependence of the work function of CdS with a variation of optical excitation. His most important results were the explanation of a decade-long puzzle, why a very thin layer of CdS on top of a CdTe thin-film solar cell causes its solar conversion efficiency to increase by a factor of two from 8% to 16%. He proved that his Böer domains limit the field at the critical pn-junction of the solar cell to 60 kV/cm, i.e., well below tunneling, and therefore eliminate junction leakage.

Mainly at IEC and SES, In.c, Böer worked on many projects relating to the development and production of solar cells and solar energy conversion. These projects were funded by agencies such as the Department of Energy (DOE), the National Research Energy Laboratory (NREL), the Solar Energy Research Institute (SERI) at DOE, the United States military, NASA, and private corporations. As evidenced in this collection, Böer maintained close contact with the emerging fields of solar energy and energy conservation by attending conferences, making public addresses, reviewing and refereeing academic publications, and serving as a consultant to industries and governments. During the 1970s, he had several government assignments on national energy panels. He was a member of the White House Office of Science and Technology Energy Assessment Panel (1972), the National Advisory Board in Solar Conservation Research (1975-1977), and a member of U.S. Senator William Roth's Delaware Energy Task Force (1974-1975). Additionally, Böer served the National Science Foundation several times, chairing the CdS Solar Cell subpanel (1973) and the Solar Heating Systems subpanel (1973).

In addition to his duties at the University of Delaware, IEC, and SES, Böer worked with various groups and organizations dedicated to the development of solar energy. Böer was an active member of the American Section of International Solar Energy Society (ISES), a professional organization that advanced the use of solar energy through the gathering and dissemination of information related to renewable energy sources. In 1976 Böer was elected to become the president of the American Section of ISES and created a professional office to incorporate it as the American Solar Energy Association (ASES). He also created its own publication office with Solar Today as its bimonthly journal and the Advances of Solar Energy as a yearly book with invited authors only. His first international solar energy conference together with the Canadian solar energy society was for the first time economically successful and published the first proceedings available to all conference participants. With Pergamon Press purchasing the surplus volumes, this created a substantial profit for ASES. After his tenure as president, Böer went on as the treasurer and director of the publication office. The society went from substantial financial problems before to a well-funded society as Böer retired from his office in 1993. ASES opened an office at the University of Delaware in 1978, and eventually became a main office for the organization's publication projects.

In 1995, Böer was named to the advisory board of WISTA, a Science and Technology Center in Berlin-Adlershof, serving as the group's U.S. Representative. Delegates from WISTA toured the United States in order to promote greater technological, educational, and industrial cooperation between the U.S. and Berlin-Adlershof.

In 1987, the University of Delaware established the Karl W. Böer Solar Energy Medal of Merit in Böer's honor. The Award was directed by Dr. Stanley Sandler, Chemical Engineering, (1992-1996); Dr. Gerard Mangone, Maritine Law, (1996-1999); Dr. Robert Birkmyre, Director IEC (2000-2009); Dr. George Hadjipanayis, Physics Department (2010-2013); and Dr. Michael Klein, ISE Lab (2014-present). The candidate is suggested by a letter from the nominator and supported by six letters from experts in the field. The package is then sent to a committee consisting of ten referees, including Ralf Böer, Chair; the presidents or chosen delegates of ASES, ISES, IEEE, NREL, DOE, APS, AChES, ASEE, and AMCE. The Karl W. Böer Foundation is a 501(c) foundation under the treasurer of the University of Delaware with $380,000 original donation that has increased to $1.3 million. The Award is given biannually in a two-day event starting with a dinner given by Renate Böer for the Awardee and distinguished guest on the first day, followed by the presentation of the medal by Böer and the financial part of the Award in form of a check by the University of Delaware president, and the presentation by the Awardee on his work that let to the Award. A black-tie dinner at the University president's home concludes the celebration.

Former President Jimmy Carter was the first recipient of the award in 1993, recognized for his work in focusing the word's attention on solar energy. President Carter installed solar panels on the White House and declared that global solar energy conversion is serious and deserving of broad based research, development and industry attention. Honorees of the Karl W. Böer Solar Energy Medal of Merit receive a bronze medal and a $60,000 stipend. Later awards were given to the following:

1995: to Dr. David Carlson, USA, who invented the first Thin-Film amorphous Silicon Solar Cell with 5% Efficiency, leading to commercial interest.

1997: to Prof Adolf Götzberger, Freiburg Germany: who demonstrated with the first Solar PV/hydrogen House a self-contained operating system with energy storage und use of hydrogen for heating and cooking as well as regenerating electric energy via fuel cells at night.

1999: to Dr. Stanford Ovshinsky, USA: for breakthrough in large scale Commercialization of his improved Amorphous Silicon solar cell with 12% efficiency and >15 year life expectancy.

2001: to Prof Allen Barnett, USA: who commercialized in large-scale production, thin-slice, material saving, single crystal silicon solar cell panels with 18% efficiency demonstrating the first price breakthrough for private consumers.

2003: to Prof. Martin Green, Australia: who sets the world Record with 23.5% solar conversion efficiency, stimulates production for application with high conversion needs (outer space) and is extremely successful educator with books and some of his students becoming the wealthiest Si-entrepreneurs in China and the next generation Si cell inventors.

2005: to Prof. Yoshihiro Hamakawa, Japan: who is the initiator and leader of the Sunshine Program that advances Japan to a leadership in PV. He also improved in his own research the copper-indium-di-arsenide solar cell in the top ranking of polycrystalline solar cells and made these competitive in the present solar cell market.

2007: to Dr. Lawrence Kazmerski, USA: who is a world authority and leader in progress analysis of every solar cell and panel for NREL certification of performance. He is the leader for selecting the government sponsorship of most promising proposals.

2009: to Dr. Herrmann Scheer, Germany: who as member of the German Bundestag was instrumental of introducing the 50 Eurocent tariff for PV-harvested electric power fed back into the Utility Grid, that permitted Germany to become the world leader with 40% electric power from solar. His initiative spread rapidly to many European countries.

2011: to Prof. Richard Swanson, USA: Stanford professor, who is the inventor of Si-single crystal solar cells with all contacts moved from the sun side to the back of the cell, improving the conversion efficiency by more than 2% and the life expectancy to a century.

2013: to Prof Zhores Alferov, Nobel Laureate, and Prof VlacheslavAndreev, Russia, who invented and further developed multi-layer poly-crystalline III/V solar cells that, on top of each other, converted additional parts of the polychromatic sunlight and herewith increased substantially the use of the solar spectrum into electric power.

With these Awardees, the Karl W. Böer Solar Energy Award has become the most prestigious award for the global solar energy community. The proposed awardees have presently a waiting list for an average of five years.


Introduction to Special Issues of Progress in Photovoltaics: The Thin Film Photovoltaic Symposium Commemorating the 25th Anniversary of the Institute of Energy Conversion at the University of Delaware.Editors: Robert W. Birkmire and Steven S. Hegedus. Newark, Del.: IEC, University of Delaware, 1997.

"Karl Böer." The Complete Marquis Who's Who. Marquis Who's Who, 2003. Reproduced in Biography Resource Center. Farmington Hills, Mich.: The Gale Group, 2003.

"Karl Böer." Who's Who in Technology. Detroit: Gale, 1989. 6th ed. Okonowicz, Ed. "Karl W. Boer appointed to German scientific board."

UpDate. Newark, Del.: University of Delaware. 8 February 1996. 1-3.

Additional biographical information supplied by Dr. Böer, e-mail to the Library, November 10, 2014.

Career Summary






Scope and Contents

The Karl Wolfgang Böer papers, 1945-2003, document the life work and professional career of this German-American physicist, inventor, university professor, and solar energy pioneer. Böer's work in solid state technology, understanding the photoconductivity and structure of cadmium sulfide, and photovoltaics are seminal to twentieth-century advances in solar energy conversion and the modern energy conservation movements. Dr. Böer's papers are integrally related to his career at the University of Delaware, where he has been since 1961. The collection reflects a relationship with the institution that allowed Böer to fulfill his academic role and conduct scientific research, while also allowing him every opportunity to build research laboratories and pursue entrepreneurial initiatives applying advances in technologies resulting from his research.

The Karl Böer papers include technical data and laboratory notes related to the science of his work, but they also document to a large extent the process of research in the latter half of the twentieth century. Böer's management style of team research is reflected in many cases, from his early establishment of a laboratory system at the Section of Dielectric Breakdown at the German Academy of Science in the late 1950s, to the founding of the Institute for Energy Conversion and the venture with SES, Inc. Critical funding support for such initiatives came from government and industry, who saw the benefits of partnerships with universities to take scientific proposals through the stages of proof and laboratory experiments to commercially viable manufacturing. The boon for such development during the energy-conscious decade of the 1970s coincided with a government program called Research Applied to National Needs (RANN).

Other aspects of twentieth-century scientific research are demonstrated in Böer's papers as well. The international network of scholars and scientists is shown through Böer's activities in professional organizations and contributions to conferences. The role of publishing is well-documented through Böer's editorial work with journals and conference proceedings, as well as his authorship of more than 300 scientific papers and articles. The research laboratory system and sources of funding are represented through Böer's grant and contract files, research reports, and his extensive library of technical reports.

The Karl Wolfgang Böer papers span the dates 1945-2003, and comprise 148 linear feet. The collection includes all manner of documents and materials related to teaching, research, and professional activities: brochures, charts, computer disks, conference programs, correspondence, drawings, financial documents, general office files, manuscripts, news clippings, notebooks, pamphlets, patents, photographs and slide transparencies, posters, programs, published journals and publications, specifications, teaching materials, tests, theses and dissertations, travel documents, and sample CdS solar cell modules.