Enhanced Fluorescence and Stability of CsPbBr3 Perovskite Nanocrystals via MOF-5 Encapsulation with Hierarchical Pore Structures

All-inorganic perovskite nanocrystals (CsPbX 3 NCs, X = Cl, Br, I) have emerged as promising candidates for applications in light-emitting diodes (LEDs), solar cells, photodetectors, and backlight displays, owing to their exceptional optoelectronic properties, including high photoluminescence quantum yield (PLQY), long carrier lifetimes, and narrow emission bandwidths. However, the intrinsic ionic nature of these nanocrystals renders them highly susceptible to environmental degradation, limiting their practical applications. Herein, we report the synthesis of CsPbBr 3 @MOF-5 composites through a physical mixing method: room-temperature supersaturated recrystallization of CsPbBr 3 NCs, followed by encapsulation within a hierarchical porous zinc-based metal-organic framework (MOF-5). By incorporating poly(ethylene oxide)-block-poly(propyleneoxide)-block-poly(ethylene oxide) Pluronic (P123) and 1,3,5-trimethylbenzene (TMB) as structure-directing agents, the pore architecture of MOF-5 was tailored to exhibit hierarchical porosity (2-35 nm), significantly enhancing both the PLQY and stability of CsPbBr 3 NCs. The CsPbBr 3 @MOF-5 composites achieved a remarkable PLQY improvement from 22% to 56%, retained 55% of their initial PL intensity after 60 days of ambient storage, and maintained 65% of PL emission under thermal stress (298-498 K). In contrast, pristine CsPbBr 3 NCs experienced complete quenching under identical conditions. Additionally, the composite exhibited superior resistance to anion exchange when combined with CsPbBr x I 3-x NCs. A white LED (WLED) device fabricated using CsPbBr 3 @MOF-5 composite and K 2 SiF 6 :Mn 2+ (KSF) red phosphor exhibited a luminous efficiency of 20.71 lm/W, a correlated color temperature (CCT) of 5486 K, and a broad color gamut covering 133.3% of the National Television Standards Committee (NTSC) standard, underscoring its potential for advanced lighting and display technologies.