Growth of Robust Carbon Nitride Films by Double Inoculation with Exceptionally Boosted Electrochemiluminescence

Electrochemically generated chemiluminescence (ECL) has attracted significant interest over decades, ranging from fundamental studies of highly efficient electron-to-photon interconversion to practical bioassays. Nonetheless, the ECL efficiency of most emitters is low, which greatly hampers further development. Herein, we report a highly robust carbon nitride film with an unusually boosted ECL efficiency (2256 times higher than that of the reference Ru(bpy)3Cl2/K2S2O8. Double inoculation, which provided the primary interaction of carbon nitride with the substrate and the succedent growth, played a crucial role in preparation. The improved ECL efficiency was ascribed to few pinholes suppressing futile co-reagent reduction, maintenance of more orbit-delocalized heptazine subunit improving ECL kinetics, and transparency avoiding self-absorption. As a result of the exceptionally high ECL efficiency, an ultrasensitive visual DNA biosensor by the naked eye was further successfully developed.