Tailorable Matryoshka-Type Metal-Organic Framework-Upconversion Nanoparticle Composites

Metal-organic framework (MOF)-upconversion nanoparticle (UCNP) composites show tremendous potential in biomedical and photocatalytic applications owing to the synergetic effects between MOFs and near-infrared light-activated UCNPs. However, conventional MOF-UCNP composites suffer from inadequate control over components, structure, and properties, due to architectural limitations. Herein, we develop a novel matryoshka-type MOF-UCNP composite with high design flexibility through a modular strategy. The constructed matryoshka-type (MOF@UCNPs)_n (n > 1) composites feature periodically ordered MOF and UCNP modules. The unique architecture enables orthogonal control over individual modules, allowing customized integration of diverse MOFs and UCNPs into distinct layers, and endows the composites with enhanced upconversion luminescence and efficient energy transfer. In addition, the matryoshka-type architecture can spatially isolate luminophores in the composites to suppress energy crosstalk between luminophores. Furthermore, matryoshka-type composites can serve as versatile templates to synthesize MOFs with hierarchically ordered and tunable pores. These results should provide a paradigm for designing the multifunctional MOF-UCNP composite, advancing applications of MOF/UCNP-based materials in photonics, catalysis, and separation systems requiring customizable energy transfer and porosity.