August 16, 2023
John Cenker, Margherita Taddei, and Leo Zasada received the Clean Energy Institute’s 2023 Clean Energy Student Achievement Awards at the institute’s annual end-of-year seminar on May 25.
The Clean Energy Scientific Achievement Award recognizes UW graduate students who have demonstrated extraordinary productivity in clean energy research and scholarship, and have contributed meaningfully to the scientific community.
John Cenker is a fifth-year Ph.D. student in physics and a 2021-22 CEI Graduate Fellow, advised by CEI faculty member and professor of materials science & engineering and physics Xiaodong Xu. His thesis work includes several breakthroughs in 2D magnetic semiconductors, which could revolutionize energy-efficient electronics, photonics, memory, and computing technologies.
“It’s an honor to be recognized by CEI,” said Cenker. “As an undergrad, I was curious about new materials for energy applications, and it’s not uncommon for graduate students to lose sight of that when immersed in their research. But the Grad Fellowship reminded me of the big picture, and inspired me to think outside the box. It was also gratifying to engage young students with science!”
Notably, Cenker invented a technique to use mechanical strain to reversibly change the magnetic phase within a particular 2D semiconducting material, chromium sulfide bromide. CrSBr is an antiferromagnet, a type of magnetic material with the spins of its electrons aligned opposite to those of their neighbors, producing a net zero effect. But when he applied physical tension, not unlike a finger trap or a game of tug-of-war, he observed that the spins of the electrons within the material aligned to produce the familiar ferromagnetism — and reverted back when the tension was eased. Harnessing full control of the spins of electrons within semiconductors would mean information could be represented without having to move charge-carrying particles through physical features on a chip, a fundamental concept underpinning modern electrical and computer engineering.
A patent is pending for the strain device, and Cenker was invited to submit a single-author paper in Nature Review Physics on the topic. He has published five first- or co-first-author papers in Nature Physics, Nature Materials, and Nature Nanotechnologies while at the UW.
“John has shown exceptional creativity, independence, and motivation in research,” said Xu. “He has the personality to collaborate with anyone, and has been a terrific role model for several graduate, undergraduate, and high school students in our lab. For instance, an undergraduate student who he mentored for his thesis research is now pursuing a Ph.D. at Princeton Physics. These traits are major assets for a successful career as a PI!”
Cenker will complete his Ph.D. in 2023, and will continue his research into 2D materials as a postdoctoral researcher at Columbia University, advised by physics professor Cory Dean. The UW is a partner in the U.S. DOE Energy Frontiers Research Center (EFRC) on Programmable Quantum Materials (Pro-QM), which is hosted by Columbia. Xu leads the UW thrust, which includes CEI Member Faculty Alexandra Velian, Jiun-Haw Chu, David Cobden, and Matthew Yankowitz.
“I’m delighted to receive this award,” said Taddei. “I came to the UW to apply my background in photochemistry and nanomaterials to solutions for climate change, and I am grateful for CEI’s support for my research and opportunities for career development. But moreover, I’m motivated by this community of clean energy scholars!”
Taddei’s research focuses on developing perovskites, an emerging class of materials with versatile opto-electronic properties and inexpensive manufacturing costs, for thin-film solar photovoltaic (PV) cells. Perovskite PV conversion efficiencies are gradually approaching those of conventional silicon, but long-term stability remains a barrier to widespread commercialization.
Her first-author paper in ACS Energy Letters describes a new method of improving the performance of thin-film halide perovskites with ethylenediamine — a common chemical used as a building block in the industrial synthesis of consumer products like dyes, weed killers, and solvents. The thin films remained stable in ambient conditions for over 100 days, and Taddei’s new perovskite “recipe” achieved a record open current voltage for a wide-bandgap perovskite suited to perovskite-on-silicon tandem cells. Her second paper will focus on the kinetics of charge carriers within thin-film perovskites.
“Margherita is a dynamo,” said Ginger. “She is constantly in motion, and constantly elevating those around her, from Julisa Juarez, a former CEBR REU student who is now a UW PhD student on an NSF Graduate Research Fellowship, to the senior postdocs working on her project. Everyone is made better by working with her.”
Taddei is anticipated to complete her Ph.D. in 2024. To complete her thesis, she will visit the University of Oxford to collaborate with the research group of physics professor Henry Snaith, who pioneered the development of perovskites for solar PV with a landmark Science paper in 2012 and spun out the company that currently holds the commercial world record for PV conversion efficiency at 28.6%.
Outreach & Service
Leo Zasada is a fourth-year graduate student in chemistry, advised by chemistry professor and CEI faculty member Dianne Xiao. As a 2020-21 CEI Graduate Fellow, Zasada participated in virtual outreach events to integrate clean energy concepts with remote learning. In the process, he noticed that STEM outreach often excluded older audiences, so Zasada created the Science Outreach and Policy for Adults (SOPA) program. With help from UW graduate student volunteers, Zasada developed educational content related to CEI research and delivered the first series of seminars at Seattle-area senior and community centers. SOPA then surveyed attendees to find new directions for STEM and science policy presentations, such as climate change, the effects of pollution on local waterways, and the efficacy of recycling.
“Leo went above and beyond in developing SOPA,” said Danica Hendrickson, CEI’s associate director of education & workforce engagement. “This award recognizes his thoughtfulness in envisioning the program and actualizing the presentations, as well as his ability to engage his peers in community outreach — he exemplifies a Clean Energy Ambassador!”
Zasada thanked his peers in remarks at the end-of-year seminar:
“I’m humbled to be recognized, and I’m grateful for the support of all the volunteers,” he said. “I felt energized when I realized there was a platform for me to develop this program and serve a new community. I was inspired by my grandmother during the creation of this program, and was thrilled to see the enthusiasm of the volunteers who were connecting to a new audience. I’m excited for new presentations in years to come!”