Achieving Hour‐Long Organic Afterglow in Donor‐Sensitizer‐Acceptor System via Molecular Engineering of Sensitizers

Comprehensive Summary The development of pure organic long persistent luminescence (OLPL) materials with hour‐scale duration remains a formidable challenge, as their design principles are still elusive. Building upon our donor‐sensitizer‐acceptor (DSA) system, herein, we report the achievement of hour‐long OLPL by engineering the molecular structure of the sensitizer. We designed three difluoroboron β‐diketonate (BF₂bdk) sensitizers featuring biphenyl‐derived motifs with incremental modifications. All corresponding three‐component systems exhibited significant room‐temperature OLPL with remarkable afterglow durations exceeding 2 h under ambient conditions. This work demonstrates the successful realization of hour‐scale OLPL within the DSA system and underscores the pivotal role of sensitizer molecular design in enabling ultralong organic afterglow, providing a clear design blueprint for future materials.