Donor-Acceptor MOF Enabling Efficient Electrochemiluminescence Based on TSCT-TADF

Electrochemiluminescence (ECL) is an extensively studied luminescence technique recognized for its efficacy in investigating surface energy states. Effective utilization of ECL to explore and probe the charge transfer mechanisms facilitated by novel luminescent materials is crucial. In this study, we demonstrate thermally activated delayed fluorescence (TADF) based on spatial charge transfer through the precisely controlled synthesis of luminescent materials, which is achieved by incorporating phenyl-carbazole derivatives as donor guests within acceptor-hosted metal-organic frameworks (D-A MOFs). These hybrid structures exhibit superior ECL intensities compared with their monomeric counterparts. Mechanistic investigation by DFT calculation reveals that the physically separated yet spatially closed D-A configuration induces efficient intermolecular through-spatial charge transfer (TSCT), leading to efficient ECL through tuning of the dihedral angle of the guest molecules to enhance π-π interactions. This study introduces a strategy for precise modulation of spatial charge transfer at the molecular level in the programmable synthesis of ECL luminophores.