Size-selected and surface-passivated CsPbBr3 perovskite nanocrystals toward self-enhanced electrochemiluminescence in aqueous media

In this work, CsPbBr3 perovskite nanocrystals (NCs) synthesized via a ligand assisted reprecipitation method (LCPB) were discovered to emit self-enhanced electrochemiluminescence (ECL) with the surface oleylamine as both coreactant and stabilizer. Solvent regulation and tri-n-octylphosphine post-treatment were manipulated for size-selected and surface-passivated LCPB, which showed remarkable aqueous ECL performance with respects to efficiency and stability. Further thanks to the self-enhancement mode with shorter charge transfer pathway and less energy loss, ECL efficiency of this as-synthesized LCPB in aqueous solution without any extra coreactant was up to 57.08% with Ru(bpy)32+-tripropylamine system as the standard. As the proof-of-concept, the products were successfully employed for bioanalyses of hydrogen peroxide, ascorbic acid, and cancer cells based on inhibition, coreaction, and impedance detection principles, respectively. More importantly, the basic properties of LCPB in aqueous media including surface chemistry, charge transfer process, and ECL mechanism were studied systematically. Such efforts are aimed at perfecting the fundamental research of all-inorganic perovskite NCs and opening an avenue for the design of highly crystalline and luminescent perovskites as advanced ECL emitters applied in ECL domain.