Guest Molecules with Amino and Sulfhydryl Groups Enhance Photoluminescence by Reducing the Intermolecular Ligand-to-Metal Charge Transfer Process of Metal–Organic Frameworks

Micron-sized metal–organic framework (MOF) sheets were prepared using organic molecules with aggregation-induced emission (AIE) properties as ligands. The intermolecular ligand-to-metal charge transfer (LMCT) process occurs in MOF structures, resulting the disappearance of matrix coordination-induced (MCIE) effect and emergence aggregation-caused quenching (ACQ) effect. Here, we demonstrate that electron donors can compete LMCT thereby changing path excitation energy returning it to ground state, mainly form fluorescence. Organic amino or sulfhydryl groups act effective donors, reducing causing MCIE sheet. coexistence will strongly inhibit sheet, greatly enhancing Therefore, these types be used regulate photoluminescence intensity AIE-based materials. In addition, there are some multiple carboxyl hydroxyl which produce similar effects. Finally, was confirmed is highly sensitive, sheet showed distinguishable fluorescence results even addition small amount 10−9 M. Thus, a feasible idea use changes induced by sensitive sensing method for molecules.