Studies in structure and electrochemistry of halide perovskite semiconductors and covalently-functionalized carbon with applications in optoelectronic devices, energy storage, and CO₂ capture
Abstract/Contents
- Abstract
- Described here are the results of my efforts to understand and control the structural, electrochemical, and transport properties of materials under development for the field of energy generation and storage. I first give the results of transport and defect chemistry studies in halide perovskite semiconductors. These crystalline solids have risen to the forefront of applied materials science research owing to the high performance demonstrated in optoelectronic devices incorporating them as active layers and their easy synthesis at low temperatures. Despite their favorable electronic properties, defect chemistry can be shown to play a pivotal role in halide perovskite properties, and thus its understanding is crucial to the technology that uses these semiconductors. I have measured electronic and ionic conductivities in multiple perovskite compounds, and have found them to change significantly, even in nominally inert environments. The behavior of ionic and electronic transport has led to the development of defect chemistry models that successfully predict how material properties change with component activity, and point to methods to control doping, defects, and conduction in halide perovskites. I next report a method to modify the physical and electronic structure of two-dimensional halide perovskites, which are of interest for solid-state lighting and other optoelectronic applications. These materials have electronic band-gaps in the visible or near UV region of the spectrum, and typically have high exciton binding energies due to 2D electronic confinement. Zwitterionic alkylammonium molecules reliably modify the structure of 2D perovskites by incorporating additional metallic or nonmetallic ions between the 2D perovskite layers. I show that these ions modify the electronic properties; they lower exciton binding energy and introduce light emission from new photoluminescent defect states. I also give an account of the development of quinone-functionalized carbons, materials whose favorable electrochemical properties lead to potential applications as high-power lithium-ion battery electrodes and as a CO2 capture materials in electrochemical CO2 separation process. Due to the particular nature of halide perovskites and other materials included in this work, nonstandard electrochemical and synthetic methods have often been required. I end by describing the tools and techniques developed with the hope that they will help fellow researchers carry out rigorous measurements simply and effectively.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2018; ©2018 |
| Publication date | 2018; 2018 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Saldivar Valdes, Abraham |
|---|---|
| Degree supervisor | Karunadasa, Hemamala |
| Thesis advisor | Karunadasa, Hemamala |
| Thesis advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Thesis advisor | Suzuki, Yuri, (Applied physicist) |
| Degree committee member | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Degree committee member | Suzuki, Yuri, (Applied physicist) |
| Associated with | Stanford University, Department of Chemistry. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Abraham Saldivar Valdes. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis Ph.D. Stanford University 2018. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2018 by Abraham Saldivar Valdes
- License
- This work is licensed under a Creative Commons Attribution Non Commercial Share Alike 3.0 Unported license (CC BY-NC-SA).
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