New Iron Molecule Key to Cheaper Solar Energy

A newly created metal molecule developed in Sweden could be used in solar-energy and fuel applications to make them more cost efficient.

Researchers have created a metal molecule that could bring down the cost of solar cells by replacing the more expensive and rarer metals used in their production today. Specifically, a team at Lund University in Sweden has created an iron molecule that can work both as a photocatalyst to produce fuel and in solar cells to produce electricity, they said in a Lund University news release.

iron molecule
This illustration depicts a new iron molecule that could be used in the design of solar cells to make them less expensive. (Image source: Nils Rosemann, Lund University, Sweden)

Iron Is Easier

With iron present in six percent of the Earth’s crust, the metal is significantly easier to source than rare metals, such as ruthenium, osmium, and iridium, typically used in this type of technology, said chemistry professor Kenneth Wärnmark of Lund University, who led the research. “Our results now show that by using advanced molecule design, it is possible to replace the rare metals with iron, which is common in the Earth’s crust and therefore cheap,” he said in the news release.

Some photocatalysts and solar cells are based on a technology that uses metal complexes to absorb solar rays and use their energy. The problem is, these metals are typically rare and thus expensive and difficult to source, driving up the cost of the technology in which they are used.

For some time, Wärnmark and his team have worked to find alternatives to expensive metals, focusing on iron because of its prevalence. In previous research, they already produced their own iron-based molecules and proved that they could potentially be used for solar-energy applications, he said.

Glowing Long Enough

Their latest research demonstrates the development of a new iron-based molecule that can capture and use the energy of solar light for a long enough time that it can react with another molecule. The molecule also can glow long enough so researchers can, for the first time, see iron-based light with the naked eye at room temperature. Researchers published a paper on their work in the journal Science.

This new molecule shows versatility in its uses, researchers said. Its key application could be in new types of photocatalysts for the production of solar fuel in two ways—either as hydrogen through water splitting or as methanol from carbon dioxide, researchers said. Another potential use is in the production of light-emitting diodes.

Indeed, even researchers were surprised at how quickly they were able to turn an iron molecule into a material for photochemical applications, with properties on par with far more expensive and much rarer metals, Wärnmark said. “We believed it would take at least ten years," he said. His team—which also included researchers from Uppsala University and the University of Copenhagen—managed to do it in five.

Elizabeth Montalbano is a freelance writer who has written about technology and culture for 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco, and New York City. In her free time, she enjoys surfing, traveling, music, yoga, and cooking. She currently resides in a village on the southwest coast of Portugal.

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