Ultrathin‐N 2 C‐Deficient Carbon Nitride for Stabilized Enhancement of Electrochemiluminescence

Abstract In the realm of electrochemiluminescence (ECL), the issue of weak signal intensity and instability linked with pure graphitic carbon nitride (CN) is widely recognized. This study suggests a method to produce nitrogen‐deficient (N 2 C) porous ultrathin CN (UACN) using ammonium acetate and ultrasonication. The ultrathin porous nature of UACN provides numerous N 2 C defects as catalytic sites, aiding in the decomposition of K 2 S 2 O 8 , a conclusion supported by density functional theory (DFT). Importantly, N 2 C defects serve as electron traps, assisting in electron localization and enhancing the recombination of electron‐hole pairs, thereby achieving stable and intensified luminescence from UACN. In practical use, UACN, acting as an ECL emitter, is utilized in detecting the tumor marker carcinoembryonic antigen (CEA), effectively establishing a highly sensitive immunosensing platform. This study elucidates the correlation between UACN structure and ECL performance, offering crucial insights for comprehending ECL mechanisms and designing high‐performance ECL materials.