Tailoring the Energy Levels and Cavity Structures toward Organic Cocrystal Microlasers

Organic
cocrystals with unique energy-level structures are potentially
a new class of materials for the development of versatile solid-state
lasers. However, till now, the stimulated emission in cocrystal materials
remains a big challenge possibly because of the nonradiative charge-transfer
(CT) transitions. Here, for the first time, we report organic cocrystal
microlasers constructed by simultaneously tailoring the energy levels
and cavity structures based on the intermolecular halogen-bonding
interactions. The intermolecular interactions triggered different
self-assembly processes, resulting in distinct types of high-quality
resonant microcavities. More importantly, the halogen-bonding interactions
alleviated intermolecular CT and thus brought about a favorable four-level
energy structure for the population inversion and tunable lasing in
the cocrystals.