Rational preparation of broadband-light-emitting lead-halide materials
Abstract/Contents
- Abstract
- Among the various properties that two-dimensional lead-halide perovskites exhibit, their ability to emit strong, tunable photoluminescence at room temperature is particularly attractive for solid-state lighting applications. These materials' emission originates from the recombination of excitons (bound electron-hole pairs). For the majority of lead-bromide and iodide perovskites, excitonic recombination results in a narrow emission feature with a small Stokes' shift. However, in a small subset of perovskites, an additional broadband emission feature is observed which covers most of the visible light spectrum. This behavior has been attributed to exciton self-trapping, a process by which an exciton produces a lattice distortion around itself and, subsequently, becomes trapped in that distortion. The combination of the narrow free excitonic emission and broad self-trapped emission results in a photoluminescence spectrum which appears white to the human eye. While the ability for perovskites to emit broadband white light is attractive, it is currently not possible to reliably prepare perovskites which exhibit white-light emission at room temperature. In an effort to develop rational routes to obtaining white-light emission in lead-halide materials at room temperature, I studied the emission properties of lead-chloride perovskites and non-perovskite lead-bromide materials. Through observation of the lead-chloride perovskites, I find that all the materials examined exhibit broadband emission at room temperature. Further, I demonstrate that the (001) perovskites, the most common structure type, can reliably emit white light at room temperature when prepared as mixed chloride-bromide materials. I then sought to expand the search for broadband-light emission to octahedral lead-bromide materials in general. After surveying a wide variety of lead-bromide hybrid materials with varying dimensionality and interoctahedral connectivity, I find that broadband emission is common across this large and diverse family despite the differences in material dimensionality or interoctahedral connectivity. Additionally, I also find that there is no correlation between any ground state structural parameters and the broadband emission's position or breadth. These data contradict ideas which have previously been proposed for perovskites and non-perovskite materials and suggest that more detailed study of these materials is required.
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 | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Crace, Ethan James |
|---|---|
| Degree supervisor | Karunadasa, Hemamala |
| Thesis advisor | Karunadasa, Hemamala |
| Thesis advisor | Solomon, Edward I |
| Thesis advisor | Waymouth, Robert M |
| Degree committee member | Solomon, Edward I |
| Degree committee member | Waymouth, Robert M |
| Associated with | Stanford University, Department of Chemistry |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Ethan James Crace. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/cv744wt5515 |
Access conditions
- Copyright
- © 2021 by Ethan James Crace
- License
- This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).
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