"Enlightenment" on the Subject of Solar Cells
Lawrence Kazmerski delivers the 2006 Taylor Lecture
On the 50th anniversary of the development of the first practical solar cell, at Bell Labs in 1956, Lawrence Kazmerski, director of the National Center for Photovoltaics at the National Renewable Energy Laboratory at Golden, Colorado, came to Penn State to deliver the 2006 Taylor Lecture. With humor and a tremendous breadth of knowledge on the past, present, and future of solar cell technology, Dr. Kazmerski enlightened and entertained an enthusiastic audience in the HUB-Robeson Center with a multimedia presentation that included footage of old newsreels, an original solar transistor radio from the 1950s, and a current European television commercial that portrays solar energy raining from the sky in the form of batteries.
Lawrence Kazmerski (Photo credit Mike Fleck)
Kazmerski expressed the belief that the use of solar energy worldwide is at a "tipping point" for explosive development. In Germany, for instance, solar panels have been installed on 700,000 roofs and a "feed-in" tariff has been established by the German government that guarantees a high rate of return to consumers for generating electricity and returning it to the energy grid. He warned, however, that the U.S. may be losing out as other countries forge ahead with government support. "The United States is losing photovoltaic market share," Kazmerski told the audience. "We need to maintain consistent federal research funding or scientists will leave this field."
He also expressed concern with the slow process of commercializing solar technology in this country. He passed around a 1950s-era solar-powered transistor radio for the audience to inspect. "This solar-powered radio was in production within a year of the development of the first solar cell," Kazmerski said. "We don't do that anymore. We have to cut the time to market, which is currently eight years. We need to get going."
Questioning the lack of urgency Kazmerski joked, "Maybe it's all in the name. Bell called them solar batteries. That sounds better than photovoltaics."
A second generation of solar technology, with either much greater conversion efficiency or lower materials cost, is ready to come to the market, he said. This technology, which includes thin films, organics, concentrators, thin silicon wafers, will have a disruptive effect on the energy field. This is a critical time for research and development in materials science and chemistry. "If we don't invest in 3rd and 4th generation solar cell research, in 25 years we won't own them."
Penn State faculty call for aggressive energy research
In presentations given prior to Kazmerski's talk, Penn State professors Harold Schobert, Thomas Mallouk, and Digby Macdonald presented both overviews of the current energy crisis and details of their energy-related research. Schobert, who recently stepped down as director of the Penn State Energy Institute, offered a history of various energy crises that began with the Hittites 3500-4000 years ago. The Hittites, the first civilization to smelt iron, cut down all of the trees in their region to make charcoal for their iron furnaces. This led to the first energy crisis and the collapse of the Hittite civilization.
Today we are in the midst of a energy crisis of our own, Schobert told the audience. There is good reason to believe that petroleum availability will be a growing problem, as a result of civil unrest, growing demand, and Hubert's peak, which predicts a peak in production followed by a rapid depletion of finite resources. The best way to find "new" energy is to conserve what we've got and use energy more efficiently, according to Schobert. Carnot's equation suggests that the best way to raise efficiency in a closed system such as an engine or furnace is to raise the temperature. This requires new materials, "superalloys for ultrasupercritical systems."
Tom Mallouk, Dupont Professor of Materials Chemistry and Physics, agreed that energy security is a national concern but believes that the environmental problem from the accumulation of greenhouse gases may be more serious. With the growth in energy use, which is expected to double by 2050, we could be facing environmental disaster in 10 to 50 years, he said. "For students thinking about what to do with your life, this is the most important problem," Mallouk asserted.
In his solar cell research, Mallouk is using an approach that involves photonic crystals that can slow light so that it stays in the dielectric material of the solar cell longer and enhances the absorption of the red wavelengths. So far, this method has shown a 25 percent increase in the current 10 percent efficiency of traditional dye-sensitized solar cells. By contrast, silicon solar cells are already 25 percent efficient, he said, but cost too much in materials. With Penn State colleague Joan Redwing, Mallouk is trying to lower the materials cost by using silicon nanowires.
Digby Macdonald, professor of materials science and engineering, directs the Center for Electrochemical Science and Technology at Penn State. MacDonald is interested in the degradation of electrodes in fuel cells. Fuels cells are a promising technology that could produce clean energy by combining hydrogen and oxygen to produce electricity. The oxygen electrode reaction, Macdonald suggested, is one of the Achilles heals of fuel cell technology.
Within the cell, energy is produced by an electrochemical reaction that also produces hydrogen peroxide, which degrades the electrodes and reduces the fuel cell performance. The actual catalysis process is still not well understood, he said. New methods for investigating the effect of the thin oxide films (5 to 10 angstroms) that form on the platinum electrodes needed to be developed. "It's hard to measure that thin a film," Macdonald said. His group developed a formula to measure oxide film thickness by the current voltage. "Our conclusion " the thickness of the film is the most important factor in electrode efficiency in a fuel cell. Now we can try to engineer a better electrode."
Bayer makes grant for graduate fellowship
At a break in the lectures, Greg Babe, president and CEO of Bayer Material Science LLC, Pittsburgh, PA, presented Professor Gary Messing, head of the Department of Materials Science and Engineering, with a $300,000 check to endow the Bayer Graduate Fellowship in Materials Science. Mr. Babe remarked that there are 200 Penn State graduates working at Bayer Material Science and Bayer has donated $2.2 million to Penn State over the past 23 years. In thanking Mr. Babe for the gift, Dr. Messing noted that "These last few years have been special ones in our relationship with Bayer."
The Nelson W. Taylor Lecture Series in Materials Science and Engineering was established in 1969 in memory of the former head of the Penn State Department of Ceramics, who was the individual most responsible for establishing the College of Earth and Mineral Sciences as a major center for ceramic research. The Taylor Lectures consistently attracts scientists of international prominence to speak at Penn State.
