Abstract
Organic afterglow materials have drawn increasing attention for their great potential in practical applications. Until now, most of them just show the lifetimes in milliseconds or seconds, while the realization of long persistent luminescence (LPL) lasting for minutes or even hours is difficult. In 2017, Adachi and Kabe successfully realize the LPL with a duration longer than 1 hour in a purely organic system, which can be even comparable to some excellent inorganic materials. However, partially for the unclear structure-property relationship, organic LPL materials are still rather scarce, especially for the stable ones in air or aqueous solution. In this review, we present the recent progress in organic LPL, mainly focusing on the material design strategy and internal mechanism. It is anticipated that the deep understanding can be beneficial for the further development of organic LPL materials with good stability in air and even aqueous phase.