Framework-Induced\nElectrochemiluminescence Enhancement\nof an AIEgen-Based MOF Coupled with Heterostructured TiO<sub>2</sub>@Ag NPs as an Efficient Coreaction Accelerator for Sensitive Biosensing

In conventional metal–organic framework (MOF)\nluminophore-involved\nelectrochemiluminescence (ECL) systems, the aggregation-caused quenching\n commonly exists for the organic luminescent ligands, limiting the\nECL efficiency and detection sensitivity. Herein, by employing the\naggregation-induced emission luminogen (AIEgen) 1,1,2,2-tetra­(4-carboxyl­biphenyl)­ethylene\n(H<sub>4</sub>TCBPE) as a ligand, one high-efficiency ECL emitter\n(Zr-MOF) was synthesized through a simple hydrothermal reaction. Compared\nwith H<sub>4</sub>TCBPE monomers and their aggregates, the resultant\nZr-MOF possesses the strongest ECL emission, which is mainly attributed\nto the framework-induced ECL enhancement. Specifically, the heterostructure\nwas prepared by the deposition of silver nanoparticles on TiO<sub>2</sub> microflowers and utilized as an efficient coreaction accelerator.\nRemarkably, the formative heterojunction can increase the interfacial\ncharge transfer efficiency and promote the carrier separation, facilitating\nthe oxidation of coreactant tripropylamine. In this way, a novel aptamer-mediated\nECL sensing platform is constructed, achieving the sensitive analysis\nof adenosine triphosphate with a low detection limit of 0.17 nM. As\na proof-of-concept study, this work may enlighten the rational design\nof new-type MOF-based ECL materials and expand the application scope\nof the ECL technology.