Investigation on the highly fluorescent IRMOF-3/thiol-ene polymer and its ligand-based composite with 76 % quantum yield

The isoreticular metal organic frameworks-3 (IRMOF-3)/non-stoichiometric thiol-ene (OSTE) and 2-aminoterephthalic acid (BDC-NH 2 )/OSTE composites were synthesized via a photo-induced click reaction. Interestingly, through polymerization with OSTE, both the fluorescence lifetime and intensity of IRMOF-3 increased. Moreover, its two lifetimes merged into one, which could be ascribed to the inhibition of the dynamic non-radiative quenching process by the OSTE network. In contrast, the ligand maintained a single lifetime with only minor changes. The dilution effect of the thiol-ene mixed solution could effectively reduce the static photo-induced electron transfer process between the ligand and toluene molecules. After the post-synthetic polymerization (PSP) treatment, the photoluminescence quantum yield (PLQY) of IRMOF-3 was increased from 7.2 % (in toluene) to 42.3 %, and that of the pure BDC-NH 2 ligand was significantly enhanced from 1.8 % (in toluene) to 76.0 %. Moreover, when a commercially available 370-nm light-emitting diode (LED) chip was individually encapsulated by the two composites, it could emit intense indigo light. This rapid PSP treatment via the OSTE polymer holds promise for application in other excellent luminescent MOFs.