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

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.