Metal-organic frameworks (MOFs) with tunable room temperature phosphorescence (RTP) exhibit unique photophysical properties, showing significant potential in the fields of bioimaging, optoelectronics, and optical anti-counterfeiting. Herein, a ligand halogen-functionalization strategy is proposed to synthesize three pillar-layer MOFs (namely Zn-TRZ-XBA, TRZ = 1, 2, 4-Triazole; XBA = 4-Chlorobenzoic acid, 4-Bromobenzoic acid, and 4-Iodobenzoic acid). The halogen atoms, serving as functional groups, not only ensure structural consistency across the isostructural frameworks but also enable the MOFs to display tunable phosphorescence emission wavelengths (505-550 nm) and adjustable lifetimes (30.8-159.4 ms). Leveraging the distinct afterglow colors and lifetimes of these MOFs, effective optical information encryption applications were realized. The ligand halogen-functionalization strategy not only provides a simplified and efficient platform for the elucidation of factors governing phosphorescence characteristics but also offers a novel approach for the precise design of materials with tunable phosphorescence properties through the strategic introduction of halogen atoms.
Miao et al. (Thu,) studied this question.