Highly Efficient Ultralong Organic Phosphorescence through Intramolecular-Space Heavy-Atom Effect

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Metal-free organic phosphorescent materials are crucial for organic electronics and bioelectronics.
• Achieving high quantum efficiency in single-component organic phosphors remains a significant challenge.

Purpose of the Study:

• To design and synthesize novel organic phosphors with ultralong organic phosphorescence (UOP).
• To investigate the factors contributing to high phosphorescence quantum efficiency in these materials.
• To explore the potential applications of these UOP materials in flexible electronics.

Main Methods:

• Design and synthesis of two organic phosphors: PDCz and PDBCz.
• Characterization of photophysical properties, including emission lifetime and quantum efficiency.
• Experimental and theoretical studies to elucidate the mechanism of UOP.

Main Results:

• Both PDCz and PDBCz exhibited ultralong emission lifetimes exceeding 200 ms.
• The PDBCz crystal achieved an absolute phosphorescence quantum efficiency of up to 38.1%.
• Intramolecular space heavy-metal effect was identified as the key factor for highly efficient UOP, enhancing intersystem crossing.

Conclusions:

• A new platform for rationally designing highly efficient UOP materials has been established.
• The developed organic phosphors demonstrate significant potential for applications in flexible electronics.
• The findings contribute to the advancement of metal-free organic phosphorescent materials.