Stimulated Emission Properties of Sterically Modified Distyrylbenzene-Based H-Aggregate Single Crystals

J-aggregation has been shown to be beneficial for light amplification in single crystals of π-conjugated organic molecules. In the case of H-aggregation, the criteria for such processes are still under debate. It has also been shown that H-aggregate arrangements with considerable π–π overlap are detrimental for light amplification. We show here that a proper alignment of the molecules in the crystal lattice, which minimizes π–π overlap between adjacent molecules, gives rise to (random) stimulated emission from cofacial arrangements similar to that of the herringbone aggregates.