–
February 22, 2024
In conjunction with the Black History Month Celebration, SCALACS invites you to a free Virtual Seminar.
Twists in the Tale: 2D Superlattices for Electrochemistry and Magnetism
FEBRUARY 22, 2024 • 2:00 - 3:00 PM PACIFIC TIME
presented by
PROF. DANIEL KWABENA BEDIAKO
Assistant Professor of Chemistry,
University of California, Berkeley, CA
Abstract:
Superlattice structures are a powerful means of tailoring the physical and chemical properties of materials. The modification of electronic structures at electrode–electrolyte interfaces is fundamental to efficient electrochemical energy conversion processes, and the intercalation of magnetic ions between van der Waals layers tunes the correlated electronic phenomena in these quantum materials, enabling the encoding of information for ultra-fast, ultralow-power, and non-volatile storage and retrieval. This talk will describe how azimuthal misalignment of atomically thin layers produces moiré superlattices that manifest a strong twist angle dependence of heterogeneous electrochemical kinetics in the case of twisted bilayer and twisted trilayer graphene electrodes with the greatest enhancement observed near the ‘magic angles’. These effects are driven by the angle-dependent engineering of moiré superlattice flat bands that dictate the electron transfer processes with the solution-phase redox couple. In addition, the talk will discuss how transition metal dichalcogenides intercalated with open-shell transition metals represent a family of materials allowing fine control over the chemical and electronic structure of a magnetic material to tailor the interplay between magnetic exchange, and magnetocrystalline anisotropy to bring about exotic magnetic orders in two-dimensional materials or bulk crystals. The design and manipulation of superlattice structures therefore shown to serve as a versatile platform for systematically interrogating and exploiting the dependence of physical and chemical phenomena on electronic structure.
About the Speaker:
Daniel Kwabena Dakwa Bediako is a Ghanaian-British chemist. He is currently an Assistant Professor at the University of California, Berkeley, and is the Cupola Era Professor in the College of Chemistry. His research considers charge transport and interfacial charge transfer in two-dimensional materials and heterostructures. He is also a member of the Editorial Advisory Board of the Journal of the American Chemical Society (JACS).
- Cupola Era Professor in the College of Chemistry, University of Berkeley, California
- B.S. Calvin College, MI (2008)
- M.S. Massachusetts Institute of Technology, MA (2013)
- Ph.D. Harvard University, MA (2015)
- Postdoctoral Fellow, Harvard University, MA (2015–2018)
References:
- Bediako et al, Nature Materials (2024): Local atomic stacking and symmetry in twisted graphene trilayers
- Bediako et al Nanomaterials (2023): Modulating the electrochemical intercalation of graphene interfaces with α-RuCl3 as a solid-state electron acceptor
- Bediako et al ACS Nano (2023): Consequences and Control of Multiscale Order/ Disorder in Chiral Magnetic Textures