Solar Energy Gaining Ground on Fossil Fuels

What if we could harness sunlight by converting it into usable electric power for a price that’s competitive with fossil fuels? Unlike the traditionally bulky and expensive solar panels available now, solar cells would be flexible, mass-produced and printed like newspapers. Such a scenario would lead to an energy source that’s not only green – it’s free and infinite.

The potential of solar cells, or photovoltaics, has been known since the late 1800s after a French physicist discovered that light creates an electric current when exposed to certain materials. The practical applications of solar cells were first demonstrated in 1958, when they were used to help power the Vanguard 1 satellite, but what’s not been realized since is how to transform this technology into an affordable, easy and large-scale technique for producing electricity.

Research on photovoltaics is taking place all around the world, but few institutions are better positioned than The University of Texas at Austin at creating the technology that enables large-scale solar production to be achieved.

Solar cell research at the university crosses all disciplines, pairing mechanical engineers with physicists, materials science experts and chemical engineers, among others. At the heart of this hybrid collaboration is a newly established center funded by the National Science Foundation (NSF) and largely by participating industry partners.

Known as the Center for Next Generation Photovoltaics, the center is the first and only of its kind in NSF’s Industry and University Cooperative Research Program, which partners the innovative capabilities of strong research universities with the needs and expertise of industry.

The university was selected along with Colorado State University, another leader in solar cell research, to launch the center less than a year ago.

“There is a lot of pressure for us to do well,” said Brian Korgel, director of the center and chemical engineering professor in the Cockrell School of Engineering. “The goal of our center is coming up with the next generation photovoltaic technology that will be cost competitive with fossil fuels, and we have a roadmap for how to do that.”

Printing solar cells liA researcher demonstrates spraying on a solar cellke newspaper

Researchers at the center are working on a radically new approach to solar cells – one that they hope will cut manufacturing costs to one-tenth of their current price by replacing the standard process used for producing photovoltaics.

Currently, most solar cells are produced using relatively expensive materials in deposition processes that require high temperatures and are time consuming. The very nature of the process, and its costs, makes it difficult to manufacture solar cells on large area substrates, the supporting material on which a circuit is formed or fabricated, and it also limits which substrates can be used.

Through the research partnership enabled by the center, researchers at The University of Texas at Austin and Colorado State University (CSU) are developing technology that could overcome many of these challenges.

W.S. Sampath, director of CSU’s Materials Engineering Laboratory, has developed a continuous, automated manufacturing process for solar panels that uses glass coating with a cadmium telluride thin film instead of the standard high-cost crystalline silicon used in most solar cells.

Crystalline silicon is energy intensive to produce, generates a lot of waste, and requires thick layers of silicon to absorb sunlight, Korgel said. Cadmium telluride, on the other hand, needs only thin layers of materials to absorb sunlight and is drastically more affordable.Professor Brian Korgel and Graduate Researcher Vahid Akhavan in the lab

Over the past five years, Korgel and his team have developed solar cells out of nanomaterial “inks” that can be printed like newspaper or painted and sprayed onto virtually any surface, including buildings, rooftops and plastics. The inks are semitransparent, meaning they could also potentially be used on building windows.

“We’re trying to process materials that have some of the same properties as cadmium telluride but we’ll do it in a different way than anybody is doing or has done,” Korgel said. “Our partnership with Colorado State is good because we can each leverage the other’s expertise and there is a good synergy between us.”

The inks developed by Korgel were listed in Reader’s Digest top 10 list of the Next Big Things that could transform the world. Currently, the inks are converting about 6 percent of the sun’s potential energy. To be a viable commercial product, the inks must achieve at least 10 percent efficiency – a milestone that they aim to reach in the next couple of years, Korgel said.

“The technology works but photovoltaic power is still about a factor of four more expensive than coal-fired power plants,” Korgel said. “But since solar energy is much more sustainable and we don’t have the pollution problems associated with fossil fuels, there is a major incentive to research and integrate photovoltaic power into the energy grid by creating the next generation technology.”

Through the collaboration between the two universities and their industry partners, the researchers are closer than ever at reaching this goal.

How to get involved

The Next Generation Photovoltaics Center is industry funded, and research projects pursued within the center are agreed upon by industry partners and researchers at the two universities. Intellectual property generated within the center is shared by its member companies.

For more information, or to become an industry partner, view the center’s membership page.

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