Marbella, Lauren
(2016)
NMR Characterization of Metal Nanoparticle Formation, Structure, and Performance.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Analytical methods with high chemical, spatial, and temporal resolution are crucial to understanding and controlling nanoparticle properties as well as translating these discoveries into society-shaping technologies. However, approaches for the characterization of solid inorganic materials and solution phase molecular species are often disparate. One powerful technique to address this gap is nuclear magnetic resonance (NMR) spectroscopy, which can facilitate routine, direct, molecular-scale analysis of nanoparticle formation and morphology in situ, in both the solution and solid phase. This dissertation describes the application of NMR to study metal nanoparticle formation, structure, and performance with unprecedented chemical detail.
In Chapter 1, the dissertation is introduced by highlighting recent developments in the application of NMR spectroscopy to the study of noble metal nanoparticle growth, surface chemistry, and physical properties. In Chapter 2, the formation of bimetallic Au-Cu nanoparticles is studied by solution NMR techniques (in conjunction with mass spectrometry and X-ray absorption spectroscopy) to reveal the chemical mechanisms driving metal atom distribution in the final particle. Building on hypotheses tested in Chapter 2, Chapter 3 describes one of the first syntheses of Au-Co alloys at any length scale with fully tunable compositions. The magnetic and optical properties of the resulting Au-Co nanoparticle alloys are evaluated with NMR and photoluminescence spectroscopies, respectively, and are found to exhibit both high relaxivity and high brightness, making them ideal bimodal imaging agents.
Building on these studies of nanoparticle formation, NMR spectroscopy is then used to study final particle structure and physical properties. In Chapter 4, NMR is used to probe ligand shell architectures on phosphine-terminated Au nanoparticles and allow the identification of 31P-197Au coupling for the first time in nanoparticle systems – a feature which may ultimately be used to study previously NMR-inaccessible nuclei such as 197Au. This utility is highlighted in Chapter 5 where the impact of local and global crystallographic environments in Au nanoclusters are probed using 31P NMR. In Chapter 6, solid-state NMR is used to characterize the emergence of metallic behavior in degenerately doped Cu2-xSe nanoparticles as well as to reveal the structural evolution of the particle as a function of this doping.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
30 September 2016 |
| Date Type: |
Publication |
| Defense Date: |
26 July 2016 |
| Approval Date: |
30 September 2016 |
| Submission Date: |
2 August 2016 |
| Access Restriction: |
2 year -- Restrict access to University of Pittsburgh for a period of 2 years. |
| Number of Pages: |
273 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
NMR, metal nanoparticle |
| Date Deposited: |
30 Sep 2016 20:41 |
| Last Modified: |
30 Sep 2018 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/29096 |
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