Two Are Better than One: A Design Principle for Ultralong Persistent Luminescence of Pure Organics

Because of their innate ability to store and then release energy, long persistent luminescence (LPL) materials have garnered strong research interest in a wide range of multidisciplinary fields, such as biomedical sciences, theranostics, and photonic devices. Although many inorganic LPL systems with afterglow durations of up to hours and days have been reported, organic systems have had difficulties reaching similar timescales. We propose in this work a design principle based on the successes of inorganic systems to produce an organic LPL (OLPL) system through the use of a strong organic electron trap. The resulting system generated detectable afterglow for up to 7 hours, significantly longer than any other reported OLPL system. The design strategy demonstrates an easy methodology to develop organic long persistent phosphors, opening the door to new OLPL materials.