High efficient room temperature phosphorescent materials constructed with methylene molecular configuration

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Room temperature phosphorescence (RTP) is crucial for advanced optical and electronic applications.
• Developing efficient and long-lived organic RTP materials remains a challenge.
• Donor-acceptor (D-A) configurations are widely explored for RTP materials.

Purpose of the Study:

• To investigate the impact of methylene functional groups on the quantum efficiency of organic RTP materials.
• To elucidate the underlying mechanisms responsible for enhanced phosphorescence.
• To provide insights for designing high-efficiency, long-lifetime RTP materials.

Main Methods:

• Synthesis and characterization of pure organic RTP materials with donor-methylene-acceptor configurations.
• Experimental investigation of photophysical properties, including quantum efficiency.
• Computational calculations to understand the role of methylene groups and heavy atoms.

Main Results:

• The incorporation of methylene groups significantly enhances phosphorescent quantum efficiency in the crystal phase.
• Methylene groups suppress molecular deformation during excited state transitions, leading to improved interactions.
• Heavy atom effects (e.g., bromine) promote π-π interactions, accelerating intersystem crossing (ISC) and increasing the ISC rate.

Conclusions:

• Donor-methylene-acceptor molecules are promising for boosting RTP quantum efficiency.
• The addition of heavy atoms is beneficial for prolonging RTP lifetime.
• This study offers a valuable reference for the rational design of high-performance organic RTP materials.