High-efficiency electrophosphorescent copolymers containing charged iridium complexes in the side chains.

Area of Science:

• Materials Science
• Organic Electronics
• Photochemistry

Background:

• Developing efficient red-emitting materials is crucial for advanced optoelectronic applications.
• Charged iridium (Ir) polymers offer potential for tunable emission properties.

Purpose of the Study:

• To develop novel charged Ir polymers for red emission in optoelectronic devices.
• To investigate the performance of these polymers in device configurations.

Main Methods:

• Synthesis of charged Ir polymers (PFPIrPiq and PFCzIrPiq) using 2-(pyridin-2-yl)benzimidazole ligands and 1-phenylisoquinoline (1-piq).
• Fabrication and testing of multi-layer and single-layer optoelectronic devices incorporating these polymers.
• Characterization of device performance including external quantum efficiency (EQE), luminous efficiency (LE), and luminance.

Main Results:

• The charged Ir polymers exhibited exclusive Ir(1-piq)(2){N-[2-(pyridin-2-yl)benzimidazole]hexyl}(+)BF(4)(-) (IrPiq) emission, peaking at 595 nm.
• Optimized devices achieved a maximum EQE of 7.3% and LE of 6.9 cd A(-1).
• High efficiencies were maintained at high current densities, and single-layer devices also showed promising results.

Conclusions:

• The developed charged Ir polymers are effective red emitters for optoelectronic devices.
• These materials demonstrate excellent performance metrics, including high efficiency and stability.
• The study proposes a charged Ir polymer as a promising candidate for future polymer optoelectronic applications.