Boosting One- and Two-Photon Excited Fluorescence of Interpenetrated Tetraphenylethene-Based Metal-Organic Frameworks (TPE-MOFs) by Linker Installation.

Immobilizing organic chromophores within the rigid framework of metal-organic frameworks (MOFs) augments fluorescence by effectively curtailing molecular motions. Yet, the substantial interspaces and free volumes inherent to MOFs can undermine photoluminescence efficiency, as they partially constrain intramolecular dynamics. In this study, we achieved optimization of both one- and two-photon excited fluorescence by incorporating linkers into an interpenetrated tetraphenylethene-based MOF (TPE-MOF). This linker installation strategy enables fine-tuning of both crystal packing density and ligand conformations. Strikingly, the desolvated MOFs exhibit remarkable two-photon absorption (TPA) cross-sections, reaching an impressive 8801 GM. Consequently, these materials demonstrate exceptional performance in one- and two-photon excited cellular imaging of HepG2 cells. Our work introduces an innovative approach to enhancing two-photon excited fluorescence (TPEF) and broadens the scope of research into one- and two-photon excited fluorescence (1/2 PEF).