Aggregation-Induced Delayed Electrochemiluminescence Active Organic Dots Enable Ultrasensitive Analysis of...

Developing efficient, purely organic aggregation-induced delayed electrochemiluminescence (AIDECL) active emitters is attractive but remains a challenge. Herein, we developed a donor-acceptor-donor type of organic dot (OD) comprising dimethylacridine donors and a benzophenone acceptor, which exhibits AIDECL behaviors with a high ECL efficiency of 54.9% relative to the Ru(bpy)₃²⁺/TPrA system. Single-crystal data analysis in combination with theoretical calculation reveals that efficient ECL may arise from two synergistic effects: restriction of molecular rotation by multiple intermolecular interactions, favoring radiative decay of excited states, and promotion of intermolecular charge transport through compact molecular packing, both contributing to enhanced ECL efficiency. Significantly, an ECL sensor based on such ODs as emitters is constructed for ultrasensitive analysis of acetamiprid serving as one of pesticides, achieving a low detection limit of 4.5 aM. This work opens a window for the design of efficient organic ECL emitters and offers insights into the structure-performance relationships.