An efficient chemiluminescent probe based on Ni-doped CsPbBr3 perovskite nanocrystals embedded in mesoporous SiO2 for sensitive assay of L–cysteine

This study presents an efficient chemiluminescence (CL) probe based on perovskite nanocrystals (NCs) for detection of L-cysteine (L-Cys). It consists of nickel-doped CsPbBr₃ NCs embedded in the mesoporous SiO₂ matrix as CL reagent and cerium (IV) as an oxidant in aqueous environment. The probe was designed for the highly selective determination of L-Cys based on its remarkable enhancing effect on the CL intensity. The colloidal nanocomposite of nickel-doped CsPbBr₃ NCs@SiO₂ with photoluminescence quantum yield of 58% was fabricated by ligand-assisted re-precipitation method and characterized by using UV-Vis absorption, FT-IR, X-ray diffraction, and transmission electron microscopy. The sensor was utilized to determine L-Cys in the linear concentration range of 20-300 nM with a detection limit of 12.8 nM. Direct chemical oxidation of Ni-doped CsPbBr₃ NCs@SiO₂ by Ce(IV) was the single cause of the formation of the excited-state NCs and subsequent production of CL. The developed probe provides outstanding selectivity towards L-Cys over structurally related compounds. Accurate determination of L-Cys in human serum samples was achieved without interference, and the results were confirmed by HPLC method.