Stable Electrochemiluminescence of CsPbBr₃ Perovskite Nanocrystals Assisted by Graphene Oxide for Ultrasensitive Sensing

Lead halide perovskite nanocrystals (PNCs) have led to a growing number of studies focusing on electrochemiluminescence (ECL) due to their excellent optical characteristics, making them promising candidates as ECL emitters for high performance. However, because of their ionic salt nature, PNCs even protected by ligands will be dissolved rapidly in polar solvents as electrolytes. Meanwhile, the contact of interfaces among PNCs, the electrode, and the electrolyte (three-phase interface) is required to guarantee effective carrier transfer and sufficient excited-state species, leading to stable ECL signals and ultrasensitivity. Herein, a fast and convenient preparation method is first proposed for fabricating abundant three-phase interfaces by anchoring CsPbBr3 PNCs to graphene oxide (GO) functionalized with amino groups, which stabilizes the PNC structure and provides carrier transfer pathways. Consequently, the GO-assisted CsPbBr3 PNC three-phase interfaces exhibit brilliant ECL intensity in acetonitrile containing 10 mM tripropylamine (TPrA) and remain stable after more than 1 h continuous cyclic potential scans with an RSD of 6%. Finally, the method has been applied to detect cupric oleate with the detection limit down to the attomolar (10–18 M) level. This work further validates the vital role of interface state in PNCs’ ECL response and has potential in ultrasensitive analysis.