General Model Nonconventional Luminophores with Well-Defined Cluster Architectures via Scaffold Confinement

Nonconventional luminophores, characterized by their nonconjugated or small conjugated structures and unique photophysical properties, have garnered significant attention owing to their fundamental scientific importance and promising applications. Despite significant progress, a persistent challenge lies in establishing model systems with well-defined cluster structures and sizes, which are crucial for in-depth mechanism understanding and quantitative structure-luminescence relationship studies. Here, we successfully overcome this limitation by employing 3D-shaped cyclic hydrocarbon scaffolds to confine electron-rich moieties, thereby preventing the formation of extensive through-space conjugation (TSC) networks. This strategy enables the construction of emissive clusters with a defined number of electron-rich units (e.g., oxygen atoms). Our findings demonstrate that clusters with as few as four oxygen atoms can generate excitation-dependent emission with green afterglow, implying the presence of diverse emissive species with varied TSC even within these well-defined, isolated clusters, likely associated with the intrinsic complexity and sensitivity of through-space electronic interactions. This strategy thus establishes a robust platform for excluding impurity-induced emission, precisely identifying cluster structures/sizes, and moreover elucidating the correlations amongst chemical structure, electronic configuration, and photophysical property in nonconventional luminophores.