Cation-π enhanced triplet-to-singlet Förster resonance energy transfer for fluorescence afterglow

The construction of triplet-to-singlet Förster resonance energy transfer (TS-FRET) systems has significantly contributed to the advancement of high-performance optoelectronic materials, particularly in the development of metal-free organic environmental afterglow materials. Despite these notable advancements, achieving highly efficient energy transfer between luminescent donor and acceptor molecules remains a formidable challenge. In this study, we present the utilization of cation-π interactions as an effective strategy to enhance TS-FRET efficiency, with the ultimate objective of further advancing fluorescence afterglow materials. Our results demonstrate that the cation-π interaction in 1D supramolecular nanorods (1D-SNRs) enhances the dipole-dipole coupling, a crucial parameter for regulating TS-FRET between the triplet state phosphorescent donor and singlet state fluorescent acceptor. As a result, we achieved an outstanding TS-FRET efficiency of up to 97 %. Furthermore, the 1D-SNRs exhibit a long-lifetime afterglow property, which suggests their potential application as a cost-effective and secure medium for information encryption. Thus, our findings highlight the promising prospects of cation-π interactions in enhancing TS-FRET efficiency and advancing the field of organic photo-functional materials.