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Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light
Published on: September 12, 2014
Hypoxic condition-selective upconversion via triplet-triplet annihilation based on POSS-core dendrimer complexes
Kazuo Tanaka1, Hiroshi Okada, Wataru Ohashi
1Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
Bioorganic & Medicinal Chemistry
|April 16, 2013
Summary
Oxygen levels significantly impact triplet-triplet annihilation (TTA) upconversion efficiencies. Researchers found that TTA upconversion emission is strongest under hypoxic conditions and can be reversibly controlled by dissolved oxygen (DO) concentrations.
Area of Science:
- Photochemistry
- Materials Science
- Biomimetic Chemistry
Background:
- Triplet-triplet annihilation (TTA) upconversion is a process that converts lower-energy photons to higher-energy photons.
- Oxygen is known to quench excited triplet states, potentially affecting TTA efficiencies.
- Biomimetic conditions offer a relevant environment for studying molecular interactions.
Purpose of the Study:
- To investigate the influence of oxygen on TTA-supported upconversion efficiencies under biomimetic conditions.
- To explore the relationship between dissolved oxygen concentrations and anthracene emission intensity.
- To determine if TTA upconversion can be reversibly regulated by oxygen levels.
Main Methods:
- Utilized polyhedral oligomeric silsesquioxane (POSS)-core dendrimer complexes with platinum octaethylporphyrin (PtOEP) and anthracene in phosphate-buffered saline (PBS).
- Excited the solution with 540 nm light to induce TTA upconversion.
- Measured fluorescence emission of anthracene at varying dissolved oxygen (DO) concentrations.
Main Results:
- Observed strong fluorescence emission of anthracene only under hypoxic conditions.
- Demonstrated that emission intensity via TTA upconversion is reversibly regulated by DO concentrations.
- Quantified the impact of oxygen quenching on the upconversion process.
Conclusions:
- Dissolved oxygen significantly influences the efficiency of TTA-supported upconversion.
- Hypoxic conditions are optimal for achieving strong TTA upconversion emission in this system.
- The TTA upconversion system exhibits reversible oxygen sensing capabilities.
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