Crystal Structure of a Highly Luminescent Slice Crystal Grown in the Vapor Phase: A New Polymorph of 2,5-Diphenyl-1,4-distyrylbenzene

We prepared a large slice crystal of trans-DPDSB with a regular shape by the physical vapor transport method and determined its crystal structure, which is different from the needle-like crystal grown in a mixture of chloroform and methanol. In the slice crystal, all of the molecules are packed in layer-by-layer mode with the same molecular orientation, and in one molecular layer, the molecules are packed in a “brick wall” motif (J-aggregate). The crystal has a very high luminescence efficiency of 48 ± 4%, attributed to the special molecular dipole stacking mode, and stimulated emission is observed under optical pumping.