Supramolecular Charge-Transfer Approach for Tunable and Efficient Circularly Polarized Delayed Fluorescence and...

Area of Science:

• Organic electronics
• Photophysics
• Supramolecular chemistry

Background:

• Circularly polarized luminescence (CPL) in organic systems is crucial for advanced optical applications.
• Organic phosphors offer high quantum yields by utilizing triplet states.
• Supramolecular charge-transfer (CT) interactions can enhance CPL performance, but their use in triplet-harvesting systems is underexplored.

Purpose of the Study:

• To introduce a supramolecular strategy for efficient and tunable circularly polarized thermally activated delayed fluorescence (TADF) and phosphorescence.
• To explore the role of intermolecular triplet CT states in achieving high CPL performance.
• To demonstrate a modular design for tuning emission colors.

Main Methods:

• Utilized through-space intermolecular CT interactions between pyromellitic diimides (acceptors) and phenyl carbazole derivatives (donors).
• Employed heavy atom-substituted bis-chromophoric acceptors.
• Investigated achiral donor molecules for supramolecular assembly.

Main Results:

• Achieved one of the most efficient circularly polarized delayed luminescent systems.
• Obtained a high quantum yield of approximately 46%.
• Demonstrated a significant luminescence dissymmetry factor (|g_lum|) of ~3.6 × 10⁻².
• Showcased tunable emission from orange to deep-red by varying donor units.

Conclusions:

• The supramolecular strategy effectively utilizes intermolecular triplet CT states for efficient CPL.
• This approach provides a modular and tunable platform for designing organic phosphors with high performance.
• Opens new avenues for developing advanced CPL-active organic materials.