Carborane-Decorated Siloles with Highly Efficient Solid-State Emissions - What Drives the Photophysical Properties?

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Carboranes and siloles are known for aggregation-induced emission (AIE).
• Developing novel AIE materials with tunable properties is crucial for advanced optical applications.

Purpose of the Study:

• To synthesize and characterize new hybrid molecules linking carborane and silole units.
• To investigate the structure-property relationships governing the photophysical behavior, particularly AIE, in these novel hybrids.

Main Methods:

• Synthesis of carborane-silole hybrids.
• Photophysical characterization (quantum yield measurements in solution, aggregated state, and solid-state).
• Single-crystal X-ray diffraction (SC-XRD) for structural analysis.
• Density functional theory (DFT) calculations to understand electronic properties.

Main Results:

• Most synthesized hybrids showed weak emission in solution and aggregated states but strong solid-state emission.
• Achieved solid-state quantum yields up to 100%.
• SC-XRD data revealed that molecular packing, influenced by carborane and phenyl moieties, is key to tailorable quantum yield.
• DFT calculations indicated that the silole unit primarily dictates photophysical properties, while carborane acts as a steric scaffold.

Conclusions:

• The carborane-silole hybrids demonstrate significant potential for solid-state emissive applications.
• Molecular packing in the crystal lattice is a critical factor for achieving high quantum yields in these systems.
• The silole moiety is the primary driver of photophysical properties, whereas the carborane unit influences molecular arrangement and steric effects.