Citation
Michelsen, Jonathan Malte Zschiegner (2024) Measuring Charge Carrier and Structural Photodynamics at Solar Energy Material Surfaces Using Transient Extreme Ultraviolet Reflection Spectroscopy. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/73h7-kg35. https://resolver.caltech.edu/CaltechTHESIS:05082024-165921385
Abstract
Electronic and vibrational degrees of freedom, and their interactions, control the chemical and physical properties of solids. Core-level spectroscopies, such as transient extreme ultraviolet (XUV) spectroscopy, provide detailed information on the electronic structure and local coordination environment of a material. In this work, we employ transient XUV reflection spectroscopy to measure surface carrier and structural dynamics in solar energy materials. To interpret experimental spectra, excited state valence effects are incorporated into the OCEAN code (Obtaining core excitations from ab initio electronic structure and the NIST Bethe-Salpeter equation solver). The modeling of core-level spectra from first principles enables the extraction of carrier kinetics via the robust assignment of spectral features. Moreover, this thesis explores experimental and theoretical methods for understanding carrier-structural coupling in solids relevant to solar energy applications.
Specifically, we explore the chemical and physical information contained in core-level spectra for various solar energy material systems and present guiding principles for designing a core-level electronic spectroscopy experiments to determine photoexcited carrier and structural dynamics. We report on experimental measurements of ultrafast surface carrier and structural dynamics in photocathodes zinc telluride and copper iron oxide. Further, complementary excited state theory is presented to extract excited state valence dynamics from experimental core-level spectra based on ground state implementations of the Bethe-Salpeter equation.
| Item Type: | Thesis (Dissertation (Ph.D.)) | |||||||||
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| Subject Keywords: | spectroscopy, photodynamics, solar energy materials, excited state dynamics, carrier-phonon coupling | |||||||||
| Degree Grantor: | California Institute of Technology | |||||||||
| Division: | Chemistry and Chemical Engineering | |||||||||
| Major Option: | Chemistry | |||||||||
| Thesis Availability: | Public (worldwide access) | |||||||||
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| Defense Date: | 2 October 2023 | |||||||||
| Record Number: | CaltechTHESIS:05082024-165921385 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechTHESIS:05082024-165921385 | |||||||||
| DOI: | 10.7907/73h7-kg35 | |||||||||
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| Default Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 16375 | |||||||||
| Collection: | CaltechTHESIS | |||||||||
| Deposited By: | Jonathan Michelsen | |||||||||
| Deposited On: | 14 May 2024 18:28 | |||||||||
| Last Modified: | 28 May 2024 16:41 |
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