Although persistent room‐temperature phosphorescence (RTP) emission has been observed for a few pure crystalline organic molecules, there is no consistent mechanism and no universal design strategy for organic persistent RTP (pRTP) materials. A new mechanism for pRTP is presented, based on combining the advantages of different excited‐state configurations in coupled intermolecular units, which may be applicable to a wide range of organic molecules. By following this mechanism, we have developed a successful design strategy to obtain bright pRTP by utilizing a heavy halogen atom to further increase the intersystem crossing rate of the coupled units. RTP with a remarkably long lifetime of 0.28 s and a very high quantum efficiency of 5 % was thus obtained under ambient conditions. This strategy represents an important step in the understanding of organic pRTP emission.

An asymmetric molecule created by molecular heredity exhibits remarkable mechanochromism and white-light emission.

Persistencep ays off:B right persistentr oom-temperature phosphorescence from pure organic molecules was achieved by intermolecular electronic coupling of selected units in crystals. The combined advantages of their different excited-state configurations (i.e., the np*s tate with ah igh intersystem crossing ratea nd the pp* state with al ow radiative rate) results in ah ybrid intersystem-crossing process that leads to efficient persistent room-temperature phosphorescence.

An effective strategy for the molecular design of AIE-ML materials is demonstrated based on tetraphenylethene with formyl substituents.

No abstract