Efficient and stable single-doped white OLEDs using a palladium-based phosphorescent excimer.

Area of Science:

• Materials Science
• Organic Electronics
• Photochemistry

Background:

• Phenyl-pyridine ligands are typically used for stable green and red phosphorescent emitters in OLEDs.
• Excimer emission in OLEDs has been primarily limited to platinum (Pt) complexes.
• Developing stable and efficient blue emitters remains a challenge for OLED technology.

Purpose of the Study:

• To synthesize and characterize a novel tetradentate palladium(II) complex, Pd3O3.
• To investigate the potential of Pd3O3 for efficient blue and white emission in OLEDs.
• To expand the use of excimer emission for white OLEDs beyond Pt complexes.

Main Methods:

• Synthesis and characterization of the tetradentate Pd(ii) complex, Pd3O3.
• Fabrication and testing of OLED devices incorporating Pd3O3.
• Evaluation of photophysical properties, including excimer emission and quantum efficiencies.

Main Results:

• Pd3O3 exhibits highly efficient phosphorescent excimer emission, achieving blue light output.
• OLED devices using Pd3O3 demonstrated peak external quantum efficiencies of up to 27.3%.
• Warm white devices achieved power efficiencies of 67.9 Lm/W, with stable devices reaching over 81 Lm/W.

Conclusions:

• Pd3O3 is a viable candidate for stable blue and white organic light-emitting diodes (OLEDs).
• The complex expands the application of excimer-based white OLEDs to palladium complexes.
• High efficiencies and operational stability suggest significant potential for commercial applications.