Rational Design of Covalent Organic Frameworks for Enhanced Reticular Electrochemiluminescence and Biosensing...

Electrochemiluminescence (ECL) has evolved into a powerful analytical technique due to its ultra-high sensitivity, low background noise, and precise electrochemical control. The development of efficient ECL emitters is central to advancing this technology for practical applications. Covalent organic frameworks (COFs) have recently emerged as promising candidates for constructing high-performance ECL systems. The tunable porosity, ordered π-conjugated structures, and versatile modular functionalities of COFs provide fast massive transport, effective electron transfer, rapid interfacial electrochemical reaction, and enhanced ECL emission performance. This review provides a comprehensive overview of the rational design strategies and structural engineering for COF-based ECL materials at the molecular level. Linkage chemistry, monomer selection (luminophores and π-conjugated non-ECL motifs), precise framework regulation, post-synthetic modification, composite formation, and other ECL enhancement strategies were discussed for developing COF-based ECL emitter. Both the incorporation of aggregation-induced emission and intramolecular charge transfer mechanisms are included to enhance ECL efficiency. Donor-acceptor conjugation, heteroatom element content, isomerism, substitution, and dimensional direction were regarded as effective strategies to regulate the electronic structure and band diagrams for designing high-performance ECL systems. The role of COFs as both active emitters and functional scaffolds for signal amplification is critically examined. Furthermore, their diverse analytical applications across biosensing, food safety, environmental monitoring, and chiral recognition are highlighted. By correlating structural features with ECL performance, this review offers insights into the design principles of next-generation reticular ECL materials and outlines future directions for their practical deployment in sensitive and selective sensing platforms.