X-aggregates and their Influences on Solid-state Emission of Organoc Luminophores

The organic luminophores consist of a diverse array of compounds exhibiting well understood conventional emission behaviour. Though their solution-state luminescence is well established, few luminophores are capable of exhibiting bright solid-state emission. Therefore, various theories to afford high solid-state emission from organic compounds, are currently under development. The formation of cross aggregate or X-aggregate is a novel way, where the energy-consuming pi-pi stacking of planar luminophores are disrupted using steric requirements. In this review, the recent reports on the X-aggregates along with their luminescence mechanism and effect of packing on emission behaviour are discussed.