A Highly Fluorescent Dinuclear Aluminium Complex with Near-Unity Quantum Yield.

Area of Science:

• Materials Science
• Photochemistry
• Inorganic Chemistry

Background:

• Aluminium complexes are attractive for optical applications due to aluminium's natural abundance.
• Previous aluminium complexes have not achieved photoluminescence quantum yields (PLQY) above 0.7 in solution.
• Developing efficient aluminium-based fluorophores remains a key challenge.

Purpose of the Study:

• To synthesize and characterize a novel dinuclear aluminium(III) complex with enhanced photoluminescence properties.
• To investigate the photoluminescence quantum yield and excited-state lifetime in solution and solid states.
• To explore the potential of the complex in practical applications, such as fluorescent fabrics.

Main Methods:

• Facile one-pot synthesis using a readily available precursor and trimethyl aluminium.
• Photoluminescence quantum yield measurements in solution and solid state.
• Characterization of aggregation behavior (J-aggregation and aggregation-caused quenching).
• Fabrication of fluorescent fleece by embedding the complex in electrospun non-woven fabrics.

Main Results:

• The dinuclear aluminium(III) complex achieved an unprecedented photoluminescence quantum yield near unity (Φ_absolute 1.0±0.1) in solution.
• An excited-state lifetime of 2.3 ns was recorded for the complex in solution.
• In the solid state, quantum yields of 0.6 were observed despite J-aggregation and aggregation-caused quenching.
• The fluorescent fleece exhibited a high quantum yield of 0.9±0.04.

Conclusions:

• The novel dinuclear aluminium(III) complex demonstrates exceptional photoluminescence efficiency in solution, surpassing previous benchmarks.
• The complex maintains significant fluorescence in the solid state and when incorporated into non-woven fabrics.
• This work opens new avenues for developing advanced aluminium-based fluorophores for diverse optical applications.