Tuning Interfacial Electron Transfer for Boosting Electrochemiluminescence: Methods, Mechanisms, and Bioanalytical Applications

The interfacial electron-transfer process acts as a pivotal kinetic determinant of electrochemiluminescence (ECL) efficiency, governing the generation of excited-state emitters and thus dictating the intensity and stability of ECL signals. Currently, harnessing diverse nanomaterials has driven significant advances in the development of novel ECL luminophores and the activation of coreactants. However, most of these luminophores exhibit low ECL efficiency in aqueous media, and the intrinsic reaction and activation mechanisms remain ambiguous because of their complex structures and compositions. Notably, tuning electron-transfer pathways at the molecular/atomic level can not only enable efficient signal amplification but also facilitate the tracking of reaction pathways, thereby providing deeper insights into the fundamental mechanisms underlying ECL processes. This Review comprehensively summarizes advances during the past five years in tuning interfacial electron transfer to enhance ECL. Furthermore, we highlight progress in electron-transfer-mediated signal amplification strategies for highly sensitive ECL biosensing and bioimaging applications. Finally, we propose and discuss the challenges and perspectives associated with improving the ECL efficiency through the modulation of electron transfer processes. Precise regulation of interfacial electron transfer holds substantial promise for advancing ECL theories, clarifying reaction mechanisms, and expanding the scope of ECL-based bioanalytical applications.