Dimensional reduction of halide double perovskites
Abstract/Contents
- Abstract
- Dimensional reduction, or conversion of a three-dimensional (3D) structure to a lower dimensional derivative, can afford dramatic changes in a material's optoelectronic properties. While the effects of dimensional reduction on the family of lead-halide perovskites have long been studied, dimensional reduction of the more compositionally diverse family of halide double perovskites has remained largely unexplored. I investigate the effects of dimensional reduction on two electronically distinct 3D double perovskites, Cs2AgBiBr6 and Cs2AgTlBr6, through the synthesis and characterization of lower-dimensional analogues of mono- and bilayer thickness. These studies reveal that quantum confinement has a much larger effect on the optical properties of the Ag--Tl materials than on their Ag--Bi analogues due to the more delocalized electronic character of the Ag--Tl lattice. Interestingly, electronic structure calculations reveal a substantial change in bandgap symmetry upon dimensional reduction. At the monolayer limit, the indirect bandgap of Cs2AgBiBr6 becomes direct, while the direct bandgap of Cs2AgTlBr6 becomes indirect. To understand these changes, I develop a model to describe and predict the band structures of 2D halide double perovskites based on the atomic orbitals of their constituent elements which reveals the underlying factors that drive the bandgap transitions. Finally, I describe how the increased structural flexibility of the 2D perovskite framework can be used to expand the compositional and functional diversity of the perovskite family through the synthesis of a mixed-valence Cu+--Cu2+--In3+ 2D perovskite. The unusual composition of this material affords optoelectronic properties which are not commonly found in 2D perovskites of monolayer thickness
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 | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Connor, Bridget Ann |
|---|---|
| Degree supervisor | Karunadasa, Hemamala |
| Thesis advisor | Karunadasa, Hemamala |
| Thesis advisor | Bao, Zhenan |
| Thesis advisor | Solomon, Edward I |
| Degree committee member | Bao, Zhenan |
| Degree committee member | Solomon, Edward I |
| Associated with | Stanford University, Department of Chemistry. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Bridget Ann Connor |
|---|---|
| Note | Submitted to the Department of Chemistry |
| Thesis | Thesis Ph.D. Stanford University 2020 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Bridget Ann Connor
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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