Brian Korgel tests one of his printed solar cells. (UT Austin)
Using nanoparticle “inks” developed at University of Texas at Austin, solar cells could be printed more cheaply - with a roll-to-roll printing process on a plastic substrate or stainless steel. The prospect of painting the inks onto a rooftop or building is not far-fetched.

Brian Korgel, a University of Texas at Austin chemical engineer, is hoping to cut costs to one-tenth of their current price by replacing the standard manufacturing process for solar cells – gas-phase deposition in a vacuum chamber - which requires high temperatures and is relatively expensive.

Korgel and his team have been working on the solar cell–manufacturing process for the past two years. He is collaborating with professors Al Bard and Paul Barbara, of the Department of Chemistry and Biochemistry, and professor Ananth Dodabalapur of the Electrical and Computer Engineering Department.

“You’d have to paint the light-absorbing material and a few other layers as well,” Korgel said. “This is one step in the direction towards paintable solar cells.” Korgel uses the light-absorbing nanomaterials, which are 10,000 times thinner than a strand of hair, because their microscopic size allows for new physical properties that can help enable higher-efficiency devices.

In 2002, he co-founded a California-based company called Innovalight, which is producing inks using silicon as the basis. Now, Korgel and his team are using copper indium gallium selenide (CIGS), which is cheaper and more benign in terms of environmental impact.

“CIGS has some potential advantages over silicon,” Korgel said. “It’s a direct band gap semiconductor, which means that you need much less material to make a solar cell, and that’s one of the biggest potential advantages.”

His team has developed solar-cell prototypes with efficiencies at one percent. “If we get to 10 percent, then there’s real potential for commercialization,” Korgel said. “If it works, I think you could see it being used in three to five years.” Korgel also said that the inks, which are semi-transparent, could help realize the prospect of having windows that double as solar cells.

(University of Texas at Austin)