Donor-Sensitizer-Acceptor Three-Component System for Organic Long-Persistent Luminescence Materials

Room temperature organic long-persistent luminescence (OLPL) materials have garnered significant attention because of their long afterglow duration of up to minutes and even hours. However, since its discovery, only two strategies for OLPL have been developed, viz, donor–acceptor intermolecular charge transfer and two-photon ionization. Consequently, OLPL examples are quite limited, compared to others such as room temperature phosphorescence materials. Here we report a new strategy based on a donor-sensitizer-acceptor three-component system for OLPL material fabrication. <i>N</i>,<i>N</i>,<i>N'</i>,<i>N'</i>-Tetramethylbenzidine (TMB), a classic electron donor, was employed as a hole trap. The phenyl benzoate (PhB) matrix, which could capture a free electron by its ester group, was selected as an acceptor. Besides, the PhB matrix could protect excitons and radical intermediates by its crystalline structure. Importantly, we introduced difluoroboron β-diketonate (BF₂bdk) molecules as a photosensitizer to facilitate charge separation, producing TMB radical cations and PhB radical anions in the system. Eventually, the retarded charge recombination that happened at BF₂bdk gave the emergence of OLPL in the three-component system. Thanks to our large BF₂bdk library, a class of OLPL materials (20 examples) with diverse structures, controlled singlet/triplet emission nature, different colors; various afterglow duration times, and even excellent aqueous dispersity were obtained, exhibiting promising applications in information encryption and biomedical areas. © 2025 Chinese Chemical Society