What if you could, atom by atom, build any material you wanted? That’s the principle behind the groundbreaking work of Rebekka Klausen, the Second Decade Society Associate Professor in the Department of Chemistry. 

Chemists refer to themselves as one of three types, Klausen says: makers, modelers, and measurers. “I’m a maker,” she says, explaining her work as one of very few investigators who apply the concepts of rational organic synthesis to other elements in the periodic table such as silicon, thereby pushing the frontiers of materials science. Rational organic synthesis involves posing a hypothesis about how carbon-carbon bonds can be formed, and how to control the three-dimensional shape of a molecule, to make a target structure. 

More Sustainable Substitutes

Klausen’s lab develops innovative synthetic chemistry for energy-relevant materials. Specifically, the researchers are exploring the properties of carbon and silicon molecules, polymers, and other materials with the aim of making more sustainable substitutes for existing materials. One of their interests involves interactions with light. 

Consider large, rigid solar panels, for example. Today’s versions are thick partly because they’re inefficient at absorbing light, Klausen says. If they could be produced with different materials with different structures that absorb different wavelengths of light, they could be thinner, portable, more efficient, and less wasteful, she says. 

In work funded by the Department of Energy and published this year in the Journal of the American Chemical Society, Klausen’s lab demonstrated how to use structure and shape to control how silicon absorbs light. Her team found that linking together hexagon-shaped silicon molecules in a zig-zag fashion was more effective than linking them in a straight chain. 

“It really is making something that’s never been made before,” she says of her work. “It’s a unique privilege being a scientist and a synthetic chemist, and I love that I get really excited by new structures and thinking about what we can accomplish with those structures.” 

Organic Molecules as Catalysts

Klausen completed her PhD in organocatalysis—a field that uses organic molecules as catalysts for chemical reactions, and which was the subject of research which won the 2021 Nobel Prize in Chemistry. “I learned so much about synthesis and the special ability chemists have to make things really precisely,” she says. “I became very interested in how do I take that skill set and bring it in a new direction?” When Klausen joined the Johns Hopkins faculty in 2013, she began exploring the creation of synthetic materials using silicon—the Earth’s second-most abundant element after oxygen. 

One important focus of her work is sustainability. New projects underway are investigating methods to extend the life of single-use plastics, to potentially keep them out of landfills. Another in water remediation is exploring how to remove and destroy fluorinated polyfluorinated alkyl substances (PFAS), such as Teflon, that accumulate in water and don’t degrade, some of which have been associated with cancer clusters. 

Beyond training a new generation of creative thinkers, Klausen hopes to make her mark in science in a hands-on manner: “I want to be able to show that through chemistry, through synthesis, you can find new materials that create new technological opportunities,” she says. “That combination is what’s really important to me.”