Event

Title: Controlling Materials at the Level of Electrons: A Journey in Ultrafast Science from Artificial Photosynthesis to Valleytronics

Abstract: Controlling materials at the level of electrons is an outstanding scientific challenge that is ubiquitous in applications ranging from solar energy conversion to information storage. The processes that govern the behavior of electrons often occur on ultrafast timescales, necessitating the use of short laser pulses to either probe or manipulate material properties. I will first discuss my previous work using tunable metal oxide solid solutions to control electron transfer dynamics in artificial photosynthetic systems. In this work, I found that using a mixed metal oxide photoanode material altered both the conduction band density of states and the electronic states in the dye sensitizer, resulting in tunable electron transfer that I studied using a variety of tools ranging from ultrafast transient absorption to X-ray spectroscopy. Building on the description of electronic structure discussed in the first part, I will describe how new methods in solid-state high harmonic generation (sHHG) spectroscopy can provide detailed insight into the band structure, topology, and symmetry of emerging materials. I will focus on my recent efforts developing time-resolved sHHG spectroscopy to probe valley polarization and transient symmetry changes in MoSe2 before providing a brief outlook on how sHHG can be applied to contemporary problems in materials chemistry.

Bio: Dr. Jacob A. Spies is currently an Arnold O. Beckman Postdoctoral Fellow in Chemical Instrumentation at the University of California, Berkeley working with Prof. Michael Zuerch where he also serves as co-director for the California Interfacial Science Institute. At Berkeley, his research focuses on the development of time-resolved solid-state high harmonic generation spectroscopy as a new tool to study quantum materials.

Jacob earned his B.S. in Chemistry from The Pennsylvania State University in 2016 and his Ph.D. in Chemistry from Yale University in 2022 working with Prof. Charles Schmuttenmaer and Prof. Gary Brudvig. While at Yale, he also worked at SLAC National Accelerator Laboratory on the development of a synchrotron-based time-resolved X-ray spectrometer through the Department of Energy Office of Science Graduate Student Research (SCGSR) program. His Ph.D. research focused on understanding charge transport control water splitting photoelectrochemical cells using a variety of ultrafast spectroscopic probes ranging from the terahertz regime (meV) to hard X-rays (keV) under near operating conditions. 

Broadly speaking, Jacob’s research interests seek to understand the dielectric environment at solid-liquid interfaces and how emergent quantum phenomena can be leveraged in next-generation materials for energy conversion and catalysis.