Introducing Methoxy Functionality to Modulate the Lead Halide Dimensionality in Robust Metal–Organic Frameworks for Enhanced Broadband Emission

Abstract Achieving hybrid lead halides with high stability and tunable dimensionality is essential for advancing their optoelectronic applications. While numerous studies have investigated ligand functionality to modulate lead halide dimensionality and enhance photoluminescence (PL) efficiency, most efforts remain limited to labile, ionically bound structures with stability issues. Herein, two new members of lead halide‐based metal–organic frameworks are successfully synthesized by employing dimethoxy‐functionalized benzenedicarboxylate acid (2,5‐dmbdcH 2 ) as a bridging linker. This functionalization increases steric hindrance, effectively isolating 1D lead halide chains into 0D lead halide units. The 0D [Pb 4 X 2 ] 6+ (X = Cl, Br) cluster‐type units, are coordinatively linked by 2,5‐dmbdc to form two robust 3D frameworks, Pb 4 X 2 (2,5‐dmbdc) 3 . The structural deformation of the 0D lead halide units enhances photoluminescence quantum yields (PLQYs) of broadband emissions, increasing from 1.5–8.0% for TMOF‐5 to 33.4–34.6% for TMOF‐15, while maintaining excellent long‐term photostability and environmental durability. Mechanistic studies reveal that the strong interaction between charge carriers and phonons within the deformable [Pb 4 X 2 ] 6+ clusters promotes the formation of self‐trapped excitons (STEs), leading to the enhanced broadband emission observed in TMOF‐15. This work presents an effective linker‐functionalization strategy for synthesizing lead halide MOFs with both high stability and excellent PL performances.