Multifold Enhanced Photon Upconversion in a Composite Annihilator System Sensitized by Perovskite Nanocrystals

Area of Science:

• Materials Science
• Photochemistry
• Nanoscience

Background:

• Photon upconversion via triplet-triplet annihilation (TTA-UC) offers a route to surpass thermodynamic efficiency limits in single-junction solar cells.
• Harvesting sub-bandgap photons is crucial for improving solar energy conversion.
• Perovskite nanocrystals (CsPbX₃) are emerging as efficient sensitizers for photophysical processes.

Purpose of the Study:

• To investigate the enhancement of TTA-UC efficiency using mixed halide perovskite nanocrystals as triplet sensitizers.
• To explore the role of composite systems of triplet annihilators in improving upconversion performance.
• To demonstrate the potential of perovskite-sensitized TTA-UC for various light-harvesting applications.

Main Methods:

• Utilizing mixed halide perovskite nanocrystals (CsPbX₃, X = Br/I) as triplet sensitizers.
• Employing 9,10-diphenylanthracene (DPA) and 9,10-bis[(triisopropylsilyl)ethynyl]anthracene (TIPS-An) as triplet annihilators.
• Comparing upconversion efficiency in single-acceptor systems versus a composite system of both annihilators.

Main Results:

• A five-fold increase in upconversion efficiency was observed with a composite system of DPA and TIPS-An compared to individual systems.
• Perovskite nanocrystals effectively sensitized triplet-triplet annihilation upconversion.
• The study highlights the synergistic effect of using multiple annihilators.

Conclusions:

• Composite systems of triplet annihilators are crucial for enhancing TTA upconversion efficiency.
• Perovskite-sensitized TTA-UC demonstrates significant promise for applications in solar energy, biomedical imaging, and photocatalysis.
• This work provides a novel approach for efficient light harvesting and energy conversion.