A Conjugated Carboranyl Main Chain Polymer with Aggregation-Induced Emission in the Near-Infrared

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Aggregation-induced emission (AIE) materials are crucial for solid-state applications due to their high emission efficiency.
• Developing AIE materials with emission beyond 700 nm for near-infrared (NIR) applications remains a significant challenge.
• Organic semiconductors (OSCs) are increasingly explored for advanced electronic and photonic devices.

Purpose of the Study:

• To investigate the potential of ortho-carborane as an AIE-active component for designing NIR-emitting OSCs.
• To synthesize and characterize conjugated polymers incorporating ortho-carborane for NIR emission.
• To evaluate the performance of these materials in organic electronic devices.

Main Methods:

• Incorporation of ortho-carborane isomers (ortho, para, meta) into the backbone of conjugated polymers.
• Photoluminescence spectroscopy to determine solid-state photoluminescence quantum yield (PLQY) and emission maxima.
• Fabrication and characterization of nondoped polymer light-emitting diodes (PLEDs).

Main Results:

• The polymer with ortho-carborane exhibited a high solid-state PLQY of 13.4% and a photoluminescence maximum at 734 nm.
• Para and meta isomers of carborane resulted in aggregation-caused quenching, highlighting the importance of isomer structure.
• Nondoped PLEDs using the ortho-carborane polymer achieved nearly pure NIR emission (86% > 700 nm) with an electroluminescence maximum at 761 nm.

Conclusions:

• Ortho-carborane is a promising building block for creating highly efficient NIR-emitting AIE materials.
• The specific isomeric structure of carborane significantly influences AIE properties and emission characteristics.
• The developed NIR-emitting OSCs demonstrate potential for practical electronic applications, particularly in PLEDs.