Structural Softness-Rigidity Mediation Enables Multicolor Emission and Long-Lived Phosphorescence in Hf/Zr Halides.

Multicolor fluorescence, typically favored by soft environments, and phosphorescence, which relies on rigid lattices to stabilize triplet excitons, are fundamentally incompatible and hard to coexist within a single material. Here, we report a crown-ether-directed lattice assembly that integrates [HfCl6]2‒/[ZrCl6]2‒ octahedra and DB18C6@M(K+/Rb+) supramolecular, yielding four unknown organic-inorganic hybrid Hf/Zr halides. Notably, (DB18C6@K)2(CH3CN)2HfCl6 achieves an exceptional room-temperature phosphorescence (RTP) quantum yield (Φp) of 54.43%, a long lifetime of 0.8 s, and a visually discernible afterglow persisting up to 6 s. Moreover, these materials exhibit excitation-dependent multicolor emission, producing green and blue-white outputs under 302 and 365 nm irradiation, respectively. This unique multimodal luminescence originates from the synergistic interplay between the balanced soft-rigid lattice provided by the crown-ether framework and heavy-atom Hf/Zr centers, which facilitates intersystem crossing, enabling both efficient RTP and tunable multichannel pathways. It has been confirmed by the high-pressure synchrotron angle-dispersive x-ray diffraction and Raman results. Overall, this work establishes a heavy-atom-based structural mediation which may offer a generalizable route to high-efficiency, multichannel, and stimuli-responsive RTP materials.