Highly efficient phosphorescent materials based on Ir(iii) complexes-grafted on a polyhedral oligomeric...

Area of Science:

• Materials Science
• Organic Chemistry
• Photochemistry

Background:

• Development of advanced phosphorescent materials is crucial for efficient optoelectronic devices.
• Iridium(iii) complexes are widely studied for their photoluminescent properties.
• Polyhedral oligomeric silsesquioxane (POSS) offers a unique core for creating well-defined nanostructured materials.

Purpose of the Study:

• To synthesize novel phosphorescent polyhedral oligomeric silsesquioxane (POSS) materials by covalently attaching an iridium(iii) complex.
• To investigate the photophysical properties and device performance of these new POSS-based materials.
• To explore the impact of the bulky POSS core on intermolecular interactions and luminescence.

Main Methods:

• Synthesis of a new iridium(iii) complex with coumarin and carbazole-functionalized ligands.
• Covalent attachment of the iridium(iii) complex to a POSS core via hydrosilylation reaction using a platinum catalyst.
• Characterization of the synthesized POSS materials using photoluminescence spectroscopy.
• Fabrication and testing of solution-processed light-emitting devices.

Main Results:

• Successful synthesis of three new phosphorescent POSS materials with good thermal stability and solubility.
• Photoluminescence studies revealed reduced intermolecular interactions and concentration quenching due to the bulky POSS core.
• Light-emitting devices fabricated with these materials achieved a maximum external quantum efficiency (EQE) of 9.77%.

Conclusions:

• The bulky POSS core effectively mitigates aggregation and concentration quenching in iridium(iii) complexes.
• The synthesized phosphorescent POSS materials are promising candidates for solution-processed optoelectronic applications.
• This work demonstrates a viable strategy for designing high-performance phosphorescent organic materials using POSS scaffolds.