Few people are simultaneously capable of navigating a “flatland” of atomically thin materials and their electrochemical reactions to afford chemical transformations that would support a clean energy economy. UC Berkeley Chemistry Professor Kwabena Bediako is part of that select group. Growing up near Accra, Ghana, he recalls attending the trade fair where his family bought their first solar-powered water heater. Upon seeing Accra’s efforts to power streetlamps with solar energy, he began to wonder, “Why don’t we do everything like this?” This curiosity about renewable energy motivated him as he pursued chemistry in the United States. He eventually joined Professor Daniel Nocera’s lab at MIT (now at Harvard) as a graduate student. It was “an exciting time to work with Nocera,” who, at the time, was already a renowned energy researcher. There, Bediako honed his skills in electrochemistry and developed critical components for a “bionic leaf”—notable highly efficient self-repairing films that generate oxygen from water. Despite this track record in electrochemistry and the opportunities it afforded to manipulate energy at the molecular scale, he wanted a change of pace upon completing his PhD. “I think after six years becoming specialized in one thing, for me, at least, it felt very natural to get exposure to a very different field.”

Bediako has always allowed his curiosity to coexist in the background with his active pursuits. As a third-year graduate student, he found himself drawn to other fascinating topics in condensed matter physics, especially the unique class of materials that can be described as “two-dimensional.” These nearly atomically flat structures demonstrate novel properties that are tunable by chemical means, such as generating heterostructures, varying composition, intercalation with other ions for energy storage, and more. These properties are often surprising—for instance, “you could layer two insulators and get a metal or superconductor at low temperature, among other things.”

Fascinated by their exciting properties, Bediako pursued this interest as a postdoctoral researcher under renowned materials physicist Phillip Kim, who needed an electrochemist. Together, they generated several breakthroughs in the control of electrointercalation of van der Waals heterostructures, precisely controlled sequences of atomic planes which allow for deliberate engineering of chemical and physical properties. This piqued Bediako’s curiosity about how electronic charge is localized in these well-defined materials, and he went on to launch his career as an independent researcher at UC Berkeley.

Here, Professor Bediako has turned his attention to studying fundamental questions about energy transfer in these heterostructures, leveraging his roots in catalysis to push forward the understanding of design principles for controlling their electronic properties. “The more we can synthesize new materials that are well-defined and controllable, the more chances we have to probe these fundamental processes,” he says. His group has repeatedly demonstrated fine control over the construction of “twisted” multilayered heterostructures, which perform impressive feats of electrochemistry. Recently, they published results showing that with their approach to “twistronics,” they could tune the rate of an electron transfer reaction over several orders of magnitude by simply varying the relative angles of several layers of graphene, an achievement that also prompts further fundamental questions about and applications for tailoring electrochemical reactions at interfaces. In some cases, the rate enhancement exceeded predictions by existing theoretical models, indicating that something is being underestimated in the interfacial electrochemical models we use today. “We’re learning about what has always contributed to interfacial electron transfer, but in ways that maybe we haven’t fully appreciated.”

Professor Bediako feels that the study of 2D materials has transformative potential for technologies that involve electronic manipulation—including, of course, computing and energy storage. However, his lab continues to ask questions that are decidedly fundamental, pursuing his curiosities and “brilliant ideas from my students or postdocs.” He finds that “these days I get way more excited by the fundamental details of these reactions and learning new tricks to play with materials or molecules at interfaces.” Because few labs in the world are as well-equipped as his to study questions about material design and their effects on electrochemistry, we expect to learn many more tricks from the Bediako lab.