NREL’s Jerry Olson Wins Prestigious Cherry Award from IEEE
Golden, Colo. A physicist from the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) who was a pioneer in multi-junction solar cells for use in outer space and on Earth has been awarded the prestigious Cherry Award by the Institute of Electrical and Electronics Engineers (IEEE).
Jerry Olson, a principal scientist at NREL, received the award at the IEEE’s annual Photovoltaic Specialists Conference in Seattle. See the feature article on Olson at www.nrel.gov.
Olson opened the door for multi-junction solar cells by showing that a top cell of gallium indium phosphide (GaInP) and a bottom cell of gallium arsenide (GaAs) can capture and convert photons more efficiently into electricity than previous attempts at using other materials.
He and his co-workers showed that the multi-junction concentrator cells not only use a fraction of the precious electronic materials used by the thicker flat plate cells, but that they can capture more light through the course of a day.
Olson’s 1984 breakthrough was embraced by NASA, which uses multi-junction solar cells based on his invention to power most space satellites, as well as the Mars rovers, Spirit and Opportunity.
Olson, then a rookie in multi-junction solar, reviewed some technical reports on the subject and had a brand new thought. Most groups working in the field were looking for band gap combination that would yield maximum theoretical efficiency with less emphasis on the chemical and structural compatibility of the different semiconductor layers.
In essence they were “trying too hard to hit the bull’s eye,” he said.
The key was to find materials that were compatible (and more likely to be manufactured) but that still had a band gap combination that would deliver high theoretical efficiency. That combination was a top cell of GaInP with a band gap of 1.9 eV and a bottom cell of GaAs with a band gap of 1.4 eV. These two semiconductors are chemically compatible and have the same lattice constant, a measure of their structural compatibility.
The Cherry Award is named in honor of William R. Cherry, a founder of the photovoltaic community. In the 1950s, he was instrumental in establishing solar cells as the ideal power source for space satellites and for recognizing, advocating, and nurturing the use of photovoltaic systems for terrestrial applications. The William R. Cherry award was instituted in 1980, shortly after his death. The purpose of the award is to recognize individual engineers or scientists who devoted a part of their professional life to the advancement of the science and technology of photovoltaic energy conversion.
It is only awarded to scientists who are still actively contributing to the field.
Today’s PV concentrators, which can extract 30 to 40 watts out of a small 1-square-centimeter solar cell by using lenses to focus the power of a thousand suns on the cell, are a direct descendant of Olson’s multi-junction breakthrough.
Sarah Kurtz, NREL’s acting director of the National Center for Photovoltaics at NREL, joined the lab a couple years after Olson’s watershed invention. The pair has been instrumental in clearing hurdles to ensure that the GaInP/GaAs solar cell remains the top cell for efficiency.
“Jerry wasn’t dissuaded by things in the literature that might give erroneous directions,” Kurtz said. “The brilliance of his achievement was partly that he was willing to set that aside even in the face of people telling him that his approach would never work.”
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