Abstract
The energy crisis highlights the need for innovative materials and technologies to advance renewable energy and sustainability. Luminescent nanomaterials are at the forefront of this effort, offering unique properties for applications such as miniaturized light-emitting devices, solar energy conversion, and super-resolution imaging. This thesis explores two classes of luminescent nanomaterials: semiconductor quantum dots (QDs) and lanthanide-doped nanocrystals (NCs), focusing on their excited-state dynamics under strong optical excitation. The first class of materials––semiconductor QDs––exhibit size-dependent electronic and optical properties driven by quantum effects. We investigated the emission of CdSe-based QDs under strong optical excitation, investigating key challenges such as nonradiative losses due to trap states and Auger recombination. Our findings reveal how excitonic interactions influence the QD emission efficiency and stability. Additionally, we investigated the role of ultrafast trapping processes in InP-based QDs, identifying their impact on the performance of QDs as color converters for displays and as potential gain media for lasing. Lanthanide-doped NCs are the second class of materials, which are studied in this thesis for their upconversion properties, enabling infrared-to-visible light conversion. Upconversion has important applications in biological imaging and sensing. However, our findings show that local photonic effects can distort upconversion emission, complicating temperature sensing and other light-based applications in nanostructured environments. Furthermore, we find that the excited-state dynamics of upconversion are influenced by structural variations, such as core–shell vs. core-only architectures, which determine the balance between internal feeding and decay processes. Through theoretical and experimental analyses, this thesis provides insights into the behavior of QDs and lanthanide-doped NCs. This research addresses open questions on the nonradiative losses and excitation pathways under strong optical excitation. The findings advance the fundamental understanding of luminescent nanomaterials and their potential role in enabling sustainable and energy-efficient technologies.
Original language | English |
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Qualification | Doctor of Philosophy |
Awarding Institution |
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Supervisors/Advisors |
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Award date | 6 Jan 2025 |
Place of Publication | Utrecht |
Publisher | |
Print ISBNs | 978-94-6506-713-1 |
DOIs | |
Publication status | Published - 6 Jan 2025 |
Keywords
- spectroscopy
- nanomaterials
- quantum dots
- lanthanides
- excited-state dynamics