Understanding the limits of hybrid optoelectronic semiconductors : photothermal techniques and beyond
Abstract/Contents
- Abstract
- Some of our earliest artisans were pioneers of nanoengineering, building the stained-glass windows of Notre-Dame before anyone knew to define the length scale. But, today, there are fewer nano-artisans than scientists studying life at the sub 10nm scale. In this dissertation, we leverage and develop sensitive characterization techniques to further push the limits of functional devices at the nanoscale and hopefully walk away with new and exciting materials. We begin with the history and fundamental chemical developments of nanoscience, from the early days of extracting metal and semiconductive crystals from sintered glass. Followed by the vital Brus equation for quantum confinement and its optical properties. We then explore the kinetics and surface chemistry that makes up 20 yrs of scientific advancement in semiconductive nanocrystals chemistry. There is an overview of some of the standard techniques used in this work to characterize and study nanocrystals. We introduce transverse photothermal deflection spectroscopy, a very sensitive photothermal absorption spectrometer, invented by Warren Jackson at LBNL in the 1980's to study thin film single crystals, polycrystals and amorphous glasses. Photothermal deflection spectroscopy measures the photothermal heat-wave propagating into a deflection fluid and can indirectly measure optical absorptivities over the range of (0.1 -10000.0 1/cm). We review the fundamental principles and limitations of a modern-day photothermal deflection spectrometer, and how to use one of the world's most sensitive optical thermometers. Then we look at how photothermal deflection spectroscopy (PDS) can be used to study modern-day thin films and solution process materials. We show new ways to apply ultra-sensitive absorption techniques towards making better optoelectronic materials. In doing so, we introduce our first look at semiconductive nanocrystals in the form of lead sulfide. I aim to use PDS as a new tool to overcome some of the fundamental limitations still hindering the development of better near-IR materials for solar-cell and transistors. Finally, we take what we learned about studying photothermal absorption and lensing at the nanoscale to push the fundamental limits of solid-state luminescence in core-shell nanocrystals. We run into the significant challenges associated with the upper limit of the uncertainty in absolute integrating sphere techniques, based on Richard Friend's photons in and photons out approach. By borrowing inspiration from the solid-state optical refrigeration community, we develop a new calorimetric quantum yield technique that uses a heat out/ light out increasing accuracy 100x when measuring highly luminescent systems. Finally, we take advantage of this increased accuracy to synthetically build and benchmark the world's brightest quantum dot emitters. All of this builds on the hope of pushing for better and more advanced nanomachines through chemistry and spectroscopy
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 | Hanifi, David Andrew |
|---|---|
| Degree supervisor | Salleo, Alberto |
| Thesis advisor | Salleo, Alberto |
| Thesis advisor | Pecora, Robert, 1938- |
| Thesis advisor | Waymouth, Robert M |
| Degree committee member | Pecora, Robert, 1938- |
| Degree committee member | Waymouth, Robert M |
| Associated with | Stanford University, Department of Chemistry. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | David Andrew Hanifi |
|---|---|
| Note | Submitted to the Department of Chemistry |
| Thesis | Thesis Ph.D. Stanford University 2020 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by David Andrew Hanifi
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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