Synthesis and Characterization of Lanthanide-Based Nanocrystals for Novel Quantum Information and Bio-Imaging Applications

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dc.contributor.authorFrencken, Adriaan
dc.contributor.supervisorvan Veggel, Frank C. J. M.
dc.contributor.supervisorBlackburn, Arthur M.
dc.date.accessioned2023-03-21T19:48:04Z
dc.date.available2023-03-21T19:48:04Z
dc.date.copyright2023en_US
dc.date.issued2023-03-21
dc.degree.departmentDepartment of Chemistry
dc.degree.levelDoctor of Philosophy Ph.D.en_US
dc.description.abstractLanthanide ions show a wide variety of optical and magnetic properties due to their unique 4f-orbital occupations, allowing them use in e.g. telecommunication, ultra-strong magnets, and lasers. Incorporation of these ions into nanoparticles (NPs, materials sized 1-100 nm) further extends the range of applications by allowing use inside living tissue for optical and magnetic bio-imaging, and inside nano-optics. In this dissertation, the internal structure of select lanthanide-doped NPs is investigated, and novel applications in quantum information and bio-imaging are proposed. In chapter 3, the internal structure of up-converting (UC) NPs is investigated using high-resolution 2-dimensional elemental maps generated by energy dispersive x-ray spectroscopy. It was shown that ions involved in the up-conversion are not homogenously distributed inside the particles. Heating the NPs to annealing temperatures (590 °C) homogenizes ion distribution, but no increase in emission intensity was seen. The reduced emission intensity is attributed to internal OH- groups, for which evidence is shown in IR spectroscopy. Chapter 4 details trapping of UCNPs and NaYF4 NP doped with a single Er3+ ion with gold nanoapertures, and discrete emission levels are observed, suggesting the presence of individual Er3+ ions. These singly doped NPs are highly promising for use as single-photon emitters. In chapter 5, a potentially scalable and automatable method to anchor permanently singly doped NPs is presented, utilizing thiol-functionalization of the NP surface followed by capping with a photo-removable group. After trapping these NPs, removal of this group by UV light absorption results in permanent anchoring inside the gold nanoapertures, as verified with electron microscopy. Chapter 6 describes a novel bio-imaging technique that involves NPs that change their magnetic resonance imaging (MRI) contrast upon x-ray interaction with the dispersion. CaF2:Eu3+ and CaF2:Fe2+/Fe3+ NPs were made. Dose experiments at low energies (40 keV) suggest that CaF2:Eu3+ turns on as a contrast agent (CA) by reduction of Eu3+ to Eu2+ by a photo-electron. At high energies (6 MeV), CaF2:Fe2+/Fe3+ is suggested to increase contrast by oxidation of Fe2+ to Fe3+ by oxidative species. To quantify the simultaneous use of multiple CAs in mixtures, T1 (spin-lattice) and T2 (spin-spin) relaxation times are shown for mixtures of a Gd-complex and iron oxide nanoparticles in chapter 7. It is demonstrated that the contrasts of the CAs cannot be linearly added due the magnetic fields of CAs affecting each others relaxivities. It is suggested that a calibration curve needs to be used to quantify MRI CAs in a mixture.en_US
dc.description.embargo2024-08-14
dc.description.scholarlevelGraduateen_US
dc.identifier.urihttp://hdl.handle.net/1828/14917
dc.languageEnglisheng
dc.language.isoenen_US
dc.rightsAvailable to the World Wide Weben_US
dc.subjectNanomaterialsen_US
dc.subjectChemistryen_US
dc.subjectDosimetryen_US
dc.subjectElectron Microscopyen_US
dc.subjectSpectroscopyen_US
dc.subjectRare Earthsen_US
dc.titleSynthesis and Characterization of Lanthanide-Based Nanocrystals for Novel Quantum Information and Bio-Imaging Applicationsen_US
dc.typeThesisen_US

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