Date of Award
8-2024
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
School
Polymer Science and Engineering
Committee Chair
Dr. Xiaodan Gu
Committee Chair School
Polymer Science and Engineering
Committee Member 2
Dr. Derek L. Patton
Committee Member 2 School
Polymer Science and Engineering
Committee Member 3
Dr. Sarah E. Morgan
Committee Member 3 School
Polymer Science and Engineering
Committee Member 4
Dr. Zhe Qiang
Committee Member 4 School
Polymer Science and Engineering
Committee Member 5
Dr. Yoan C. Simon
Abstract
High efficiency photon upconversion via triplet-triplet annihilation (TTA-UC) is challenging to achieve in glassy materials due to hindered mobility of the upconverting chromophores and increased back Förster resonance energy transfer (back-FRET) to the triplet sensitizer at the chromophore concentrations necessary to facilitate sensitizer- annihilator energy transfers. In this dissertation, we demonstrate how to prevent back- FRET to the sensitizer by decoupling the annihilation and emission mechanism through the introduction of a third highly emissive singlet sink: 9-phenyl-10-(p-tolylethynyl)- anthracene (PTEA). The addition of PTEA dramatically improves the overall upconversion quantum yield (out of 50%) from 2.7% to 5% for compression-molded PMMA films containing a platinum (II) octaethylporphyrin (PtOEP) sensitizer and a 9,10- diphenylanthracene (DPA) annihilator. We then illustrate that by covalently tethering DPA and PTEA to the polymer backbone we can increase the practical chromophore load past the previous limits of doped systems. Acrylate-based DPA and PTEA monomers were synthesized and prepared via reversable addition-fragmentation chain transfer polymerization (RAFT), permitting facile tunability of chromophore load and placement. Direct polymerization of these aromatic chromophores makes advanced thermal processing unnecessary for manufacturing strictly glassy upconverting films. Additionally, we demonstrate that attaching chromophores directly to the polymer chain permits facile tunability of amorphous upconverting systems through the application of a sensitizer- containing chain transfer agent with reduced aggregation tendencies - thereby permitting increased sensitizer concentrations while theoretically limiting aggregation-induced quenching and back-FRET towards the full potential of TTA-UC.
Copyright
2024, Sonia T. Stanciu
Recommended Citation
Stanciu, Sonia, "Enhancing Light Upconversion by Singlet-Sink-Type Triplet-Triplet Annihilation in Polymer Glasses" (2024). Dissertations. 2270.
https://aquila.usm.edu/dissertations/2270
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