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Providing molecular-scale details at electrode interfaces through interpretation of X-ray spectroscopy

Speaker: 
David Prendergast (The Molecular Foundry, Lawrence Berkeley Natl. Lab., USA)
Date: 
Tue, 09/06/2015 - 11:00am to 12:00pm
Location: 
Physics Conference Room (S13-M01-11)
Host: 
Quek Su Ying
Event Type: 
Seminars

Abstract

The control of energy flow in devices is often dictated by materials interfaces and a detailed understanding of such interfaces under working conditions is required for their further optimization. Soft X-ray spectroscopy is an intrinsic surface sensitive probe capable of revealing molecular scale details at interfaces. Coupled with first-principles modeling of the structure and dynamics at the junction between two materials, one can begin to interpret measured spectra and to make direct connections between structure and function. Here we present details of recent studies relevant to various model electrode interfaces in the context of electrochemistry [1] and photoelectrochemistry [2], indicating the importance of first-principles theoretical simulation in the interpretation of X-ray spectroscopy and the associated insight into the processes behind interfacial energy transfer and storage.

[1] The structure of interfacial water on gold electrodes studied by x-ray absorption spectroscopy J.-J. Velasco-Velez, et al., Science 346, 831 (2014).
[2] Atomic Scale Perspective of Ultrafast Charge Transfer at a Dye-Semiconductor Interface. K. R. Siefermann, et al., J. Phys. Chem. Lett. 5, 2753 (2014).

Speaker's bio

Dr. David Prendergast is the Facility Director for Theory at The Molecular Foundry, a US Department of Energy Nanoscale Science Research Center and User Facility at Lawrence Berkeley National Laboratory. He received his PhD in Physics from University College Cork, Ireland in 2002, under Prof. Stephen Fahy, and worked as a postdoctoral fellow in the groups of Giulia Galli (then at Lawrence Livermore National Laboratory) and Steven Louie (at the University of California, Berkeley) before joining the scientific staff at The Molecular Foundry in 2007. His research focuses on the development and application of first-principles theory and high-performance computing resources to the modeling of nanoscale phenomena in materials systems. He has specific expertise in the direct simulation of X-ray spectroscopy using these methods and provides prediction and interpretation of measured X-ray spectra in complex and dynamic systems of relevance to energy harvesting and storage.

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