April 27, 2023
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4:00 PM
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5:00 PM
Dr. Thomas Kempa
Department of Chemistry and Department of Materials Science and Engineering
Johns Hopkins University
Host: Professor Dan Rhodes (MS&E)
Precision Synthesis of Quantum Material Building Blocks
Abstract
Quantum materials promise to transform the development of next-generation sensors, analytical instruments, information processing systems, and energy conversion platforms. Realizing these goals will require low-dimensional crystals whose size, shape, structure, and composition can be tailored to atomic levels of precision. Chemistry will play a vital role in creating these crystalline building blocks of quantum matter. In this vein, the Kempa group has focused on the precision synthesis of 2-dimensional (2D) materials to harness quantum phenomena. Our synthetic and spectroscopic work with 2D atomic lattices and 2D molecular frameworks has revealed that even subtle manipulations of the dimensionality and morphology of these materials yield large property changes. Notably, we can dramatically manipulate the structure of 2D transition-metal dichalcogenides by growing them on chemically tailored surfaces. The resulting nanoribbons emit light whose energy and profile show an unusual progression with crystal size. Seeking to expand the palette of available 2D materials, we have also prepared and examined new 2D metal-organic frameworks and their corresponding devices. Reversible phase switching can be induced in these frameworks with concomitant modulation of electronic transport. Because of these efforts we can now create unprecedented heterointerfaces between 2D atomic lattices and 2D molecular frameworks. These interfaces provide a platform on which to chemically tailor quantum emission, thermal transport, mechanical properties, and cooperativity among catalytically active surface sites.
Biography
Thomas J. Kempa is an Assistant Professor of Chemistry and of Materials Science and Engineering (by courtesy) at Johns Hopkins University. After receiving a bachelor’s degree in chemistry from Boston College (2004) and after being awarded a Marshall Scholarship, Tom completed two years of post-graduate study at Imperial College London. Returning to the United States, he began graduate studies under the direction of Prof. Charles Lieber at Harvard University and earned his PhD in 2012. Thereafter, Tom conducted postdoctoral studies in the laboratory of Prof. Daniel Nocera, first at MIT and then Harvard. Professor Kempa’s research group develops new methods to prepare and study low-dimensional (low-D) inorganic crystals from nanoparticles (0D) to few-atom thick sheets (2D) whose exceptional properties render them intriguing platforms for optoelectronic, energy conversion, and quantum science studies. Professor Kempa is the recipient of numerous awards including a DARPA Young Faculty Award, an NSF CAREER Award, a Toshiba Distinguished Young Investigator Award, a Dreyfus Foundation Fellowship in Environmental Chemistry, two Hopkins Discovery Awards, and a Hopkins Catalyst Award. He was also named an Emerging Investigator by the Journal of Materials Chemistry A and was recently selected by Matter as one of 35 early career PIs leading breakthroughs in materials science. Tom was also recently appointed a member of the Nano Letters Editorial Advisory Board.