Efficient Room-Temperature Phosphorescence of a Solid-State Supramolecule Enhanced by Cucurbit[6]uril

Area of Science:

• Materials Science
• Organic Chemistry
• Supramolecular Chemistry

Background:

• Efficient organic room-temperature phosphorescence (RTP) is crucial for optoelectronics and photobiology.
• Controlling phosphorescence in organic molecules remains a challenge.

Purpose of the Study:

• To investigate the enhancement of organic single-molecule phosphorescence through supramolecular assembly.
• To explore the role of counterions and host-guest complexation in modulating RTP efficiency.

Main Methods:

• Synthesis and characterization of bromophenyl-methyl-pyridinium (PY) derivatives with various counterions.
• Single crystal X-ray diffraction to analyze molecular structure and interactions.
• Host-guest complexation studies using cucurbit[6]uril (CB[6]) to form nanosupramolecular assemblies.
• Measurement of phosphorescence quantum yields under ambient conditions.

Main Results:

• PY derivatives with different counterions showed phosphorescence quantum yields ranging from 0.4% to 24.1%.
• The PY iodide (PYI) derivative exhibited higher efficiency, potentially due to halogen-bond interactions.
• Nanosupramolecular assembly of PY chloride with CB[6] resulted in a significantly enhanced quantum yield of 81.2%.

Conclusions:

• Supramolecular assembly via host-guest complexation is a powerful strategy to enhance organic RTP.
• Encapsulation by CB[6] effectively suppresses non-radiative decay pathways and promotes intersystem crossing (ISC).
• This approach offers a novel method for designing high-efficiency RTP materials.