Thermodynamically Stable Organic Dye Microcrystals for Highly Efficient Whispering-Gallery-Mode Lasing.

Area of Science:

• Materials Science
• Optics
• Organic Chemistry

Background:

• Organic laser dyes offer vast potential for miniaturized laser technology.
• Intermolecular quenching in dye aggregates hinders the realization of pure dye aggregate lasers.
• A universal strategy to activate optical gain in dye aggregates is crucial for developing miniaturized dye lasers.

Purpose of the Study:

• To propose and demonstrate a molecule-guided crystal engineering strategy.
• To synthesize thermodynamically stable organic dye microcrystals that can lase efficiently.
• To overcome the challenge of intermolecular quenching in organic laser dyes.

Main Methods:

• Introducing multiple alkyl substituents onto the organic dye molecule skeleton.
• Transforming strong intermolecular interactions into multiple weak intermolecular interactions.
• Synthesizing and characterizing organic dye microcrystals with distinct packing modes and geometries.

Main Results:

• Successfully activated optical gain in organic dye single crystals.
• Developed two types of microcrystals with different molecular packing and geometries, both enabling efficient lasing.
• Achieved highly efficient and stable whispering-gallery-mode lasing using hexagonal microcrystals with herringbone packing, exhibiting large optical gain, strong cavity confinement, and high stability.

Conclusions:

• The molecule-guided crystal engineering strategy is universally applicable to various organic laser dye skeletons and substituents.
• This approach facilitates the exploration of organic microlasers with improved performance and novel functions.
• The developed strategy provides a pathway for creating stable, high-performance organic dye lasers.