Dynamic multi-color long-afterglow and cold-warm white light through phosphorescence resonance energy transfer in host-guest metal-organic frameworks

Dynamic tuning of single-color and multi-color (including white-light) luminescence has attracted much attention for applications in various fields; however, effective systems are still scarcity to date. Herein, we report the construction of host-guest metal-organic frameworks (MOFs) serves as an effective strategy to achieve the excitation- and time-dependent long afterglow and white light emitting, simultaneously. The guest-induced structural distortion modulates the single-triplet state intersystem crossing, promotes ligand-to-ligand charge transfer (LLCT) in layer-column MOFs, and further boosts multiple exciton generation of triplet states for multi-color ultralong phosphorescence, as indicated by both experiment and density functional theory (DFT) calculation. By further doping of dyes into MOFs, white-light emitting with tunable color temperature can be facilely obtained, which has been further fabricated into white-light light-emitting diode (LED) with color rendering index of 88.4, higher than that of most as-reported pure inorganics and inorganic-organic hybrid systems. Therefore, this work not only describes a host-guest energy transfer route for dynamic tailoring wide range of color-tunable long-afterglow, but also explores the application prospect of new white-light materials with high color rendering and low blue light for promising display and lighting applications.