Cocrystallization Tailoring Multiple Radiative Decay Pathways for Amplified Spontaneous Emission.

Area of Science:

• Organic electronics
• Materials science
• Photophysics

Background:

• Amplified spontaneous emission (ASE) is crucial for lasing but hindered in organic semiconductors by inefficient energy transfer.
• Multiple competing radiative decay pathways in organic materials complicate control over ASE.
• Molecular arrangement significantly impacts radiative decay and ASE properties, yet remains poorly understood.

Purpose of the Study:

• To achieve controllable molecular packing in organic semiconductors.
• To enhance radiative decay rate and ASE selectivity.
• To reduce the amplified spontaneous emission (ASE) threshold in organic materials.

Main Methods:

• Utilizing halogen-bonded cocrystallization to engineer molecular packing motifs.
• Investigating the relationship between molecular arrangements, vibration modes, and radiative decay profiles.
• Analyzing amplified spontaneous emission (ASE) properties and threshold reduction.

Main Results:

• Achieved controllable molecular packing through cocrystallization.
• Increased radiative decay rate by ten times and ASE radiative decay selectivity by four times.
• Significantly decreased the ASE threshold from 223 to 22 μJ/cm², despite a low photoluminescence quantum yield.

Conclusions:

• Cocrystallization is a powerful strategy for tailoring radiative decay pathways in organic semiconductors.
• Controlling molecular arrangements is fundamental for developing efficient organic ASE and lasing materials.
• This work provides insights into optimizing photon energy transfer for advanced organic optoelectronic devices.