Beyond the Hill

University of Vermont professor researches possibility of printable solar cells

Courtesy of Matthew White

University of Vermont Professor Matthew White's research on solar cells is cost and energy-effective, but also — in the end — printable.

A professor at the University of Vermont is well on his way to creating solar technology that’s cheap, stable, highly efficient and as easy to implement as it is to click “Print.”

Matthew White, a professor of physics at the University of Vermont, has dedicated 12 years of scientific research toward the innovation of tiny, individual solar cells that will not only be cost and energy-effective, but also — in the end — printable.

The concept is rooted in two basic ideas, White said. The first: Colored inks are good candidates with which to create solar cells, since they’re extremely inexpensive, relatively stable and able to absorb light. The second: Newspaper printers, which use colored inks to create their final product, can print a large area very quickly and for very little money. Combine the two and you have printable solar cells.

“The long-term goal is to come up with a way to make solar energy from materials that are extremely cheap, not only in and of themselves, but easy to process so that you can make really large-scale power generation from the sun without having it be extremely expensive,” White said.

The search for the perfect material has been difficult, though. White said he and his team have spent plenty of time testing and analyzing a multitude of possibilities to ensure the chosen base meets the desired traits.

“We want materials that are also high efficiency and also very stable if you expose them to air and water — which is pretty much everywhere — and materials that are very cheap,” White said. “We’ve been looking at materials that meet all three of those criteria.”

He added that some prospective materials include the magenta color in inkjet printers, pink hair dye and the blue dye in denim jeans.

White said he and his team couldn’t just search for a base material at random — if they did that, they would be “stumbling in the dark forever.” Rather, they analyzed both materials they had a hunch about and materials toward which they were skeptical to make sure all bases were covered.

They began with pigmented options, since hue is a sign of light absorption.

“If you’re looking for materials that absorb sunlight, color is a real obvious one,” White said.

Less obvious, though, was the possibility of quinacridone — or the organic molecule found in pink hair dye and other pigmented products — as a successful material, White said. Either way, he’s glad his team tried it out.

“Some of the materials are shocking how well they work,” White said, “Just based on your intuition you would discard them and not try them any further, so there’s a certain advantage to saying, ‘Well let’s try it anyway.’”

Quinacridone molecules are hydrogen-bound, White said, allowing molecules to stack closely together and thus improve both performance and stability. He added that the material is cheap, too — just 25 cents a kilogram.

When all is said and done, White’s individual solar cells will revolutionize the way society uses and renews energy.

“These things are incredibly lightweight, incredibly thin. And you can stick them to almost anything,” he said. “You could use them just by themselves, if you were backpacking and wanted to carry solar cells with you. They weigh nothing.”

Or, he added, they could be rolled out to cover the top of an airplane and only add a few grams of weight.

Although White and his team weren’t the first to explore this avenue of solar energy, they’ve made strides in the right direction.

“People have been working on driving this direction for … 30 years or so, but I and some of the people I’ve been working with have been able to make some pretty significant impacts over the last couple years,” White said.


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