Triplet-Fusion Upconversion Using a Rigid Tetracene Homodimer

Area of Science:

• Photochemistry
• Materials Science
• Organic Chemistry

Background:

• Triplet fusion upconversion (TUC) typically uses monomeric molecules.
• Solution-phase TUC often suffers from concentration-dependent efficiency.
• Developing new molecular architectures is crucial for advanced TUC applications.

Purpose of the Study:

• To investigate the potential of a structurally rigid molecular dimer as a replacement for monomeric annihilators in TUC.
• To explore the unique photophysical properties of a norbornyl-bridged tetracene homodimer in TUC.
• To circumvent the concentration dependence of solution-phase TUC.

Main Methods:

• Excitation of a triplet sensitizer at 730 nm.
• Observation of emitted photons at 540 nm from the molecular dimer.
• Analysis using steady-state spectroscopy, kinetic simulations, and Stern-Volmer quenching experiments.

Main Results:

• The molecular dimer functions as an effective annihilator for TUC.
• The dimer exhibits distinct photophysics compared to its monomer, with reduced diffusion-mediated triplet transfer but enhanced triplet fusion.
• The dimer's performance is less dependent on concentration.

Conclusions:

• Structurally rigid molecular dimers can serve as efficient alternatives to monomers for TUC.
• The unique photophysics of the dimer enable more efficient triplet fusion.
• This approach offers a pathway to overcome concentration limitations in solution-phase TUC.