Co-crystallization and Clustering Afforded Simultaneously Boosted Efficiency, Lifetime, and Color Tunability of Organic Afterglows.

Pure organic persistent room-temperature phosphorescence (p-RTP) is in urgent demand for advanced optoelectronic and bioelectronic applications. However, it remains an enormous challenge to modulate the emission colors while simultaneously boosting the phosphorescence lifetimes and efficiencies. Herein, we report the co-crystallization between melamine and cyclic imide-based non-conventional luminophores, which affords co-crystals owning multiple hydrogen bonds and effective clustering of electron-rich units, thus resulting in diverse emissive species with highly rigidified conformations and promoted spin-orbit coupling. Consequently, p-RTP co-crystals with simultaneously enhanced efficiencies and lifetimes of up to 12.0% and 898 ms, alongside remarkably improved color tunability, are obtained. These results may spur the future rational design of high-performance p-RTP materials and advance the mechanism of understanding of the origin of color-tunable phosphorescence.