Iron-based Chalcopyrite CuFeX₂ Nanocrystals and Surface Passivated CuFeX₂/ZnS (X = S and Se) Core/shell Architecture: Synthesis, Structural, Morphological, Optical and Biological Activities

Abstract: The iron-based chalcopyrite (I-III-VI₂) of CuFeX₂ nanocrystals (NCs) and their surface passivated CuFeX₂/ZnS core/shell NCs were prepared by hot injection method. The existence of broad absorption peaks in the Ultraviolet-visible (UV-Vis) spectroscopy analysis as well as the higher peak intensity in PL study compared to unpassivated CuFeX₂ NCs confirms the ZnS passivation over CuFeX₂. The UV-Vis and Cyclic voltammetry (CV) measurements confirm the band gap in the range of 1.78 eV (CuFeS₂) and 1.35 eV (CuFeSe₂) for surface passivated CuFeX₂ (X = S, Se), which are much higher than those of the bulk materials of their counterpart. X-ray diffraction (XRD) analysis reveals that both CuFeX₂ and CuFeX₂/ZnS have similar tetragonal structure. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis also confirm the ZnS passivation over CuFeX₂ (X = S, Se) NCs, by the appearance of a quasi-cubes with significant proportion of irregular shapes. Their EDX measurement agrees with the elemental composition present in the existing systems. The bioimaging study of CuFeX₂/ZnS NCs were analyzed by recording their cytotoxicity study for micelle encapsulated CuFeX₂/ZnS core/shell NCs with various concentrations on human lung cancer cells (A549) using the MTT assay, and it reveals that cell viability increases with the increased core/shell NCs concentrations. Their antibacterial study was also revealed the same trend.