Fool’s gold could shine in solar cells

Photonics : Although iron pyrite, otherwise known as iron sulfide or fool’s gold, was tossed aside by miners more than a century ago, it may prove to be worth its weight in gold as a thin-film solar cell material. Researchers at Oregon State University have found that iron pyrite, which contains two of the most abundant elements on Earth, is an excellent absorber of solar energy and can be made into extremely thin layers. Unfortunately, the substantial heat required to create solar cells causes the pyrite to decompose. So the researchers tried an inverse design approach. “We identified the failure mechanism of pyrite, formulated a few design rules that preserved the favorable aspects of pyrite, and identified [iron silicon sulfide] and [iron germanium sulfide] as new absorber candidates,” said Douglas Keszler, coauthor of a paper published in Advanced Energy Materials. But much more work remains to be done. It could take at least 10 more years to fine-tune a marketable alternative to traditional solar cell materials.