Synthesis and Characterization of Novel Sprayed Ag-Doped Quaternary Cu2MgSnS4 Thin Film for Antibacterial Application.

In this work, the effects of silver doping with different Ag/(Ag + Cu) ratios (i.e., 2%, 5% and 10% at.% in the spray solution) on the structural, morphological, optical, electrical and antibacterial properties of Cu2MgSnS4 (CMTS) thin film grown by spray pyrolysis have been studied. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) results have shown that the kesterite phase of CMTS thin films has a maximum crystallite size of about 19.60 nm for 5% Ag/(Ag + Cu). Scanning electron microscopy (SEM) images have shown spherical grain shapes. The transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) microscopy observations confirmed the intrinsic reticular planes of CMTS thin film with (112) as a preferred orientation and interplanar spacing value of 3.1 Å. The optical properties showed high absorbance and an absorption coefficient of about 104 cm-1 in the visible region with an optical band gap energy of 1.51 eV. Impedance analysis spectroscopy demonstrated good electrical properties of the CMTS film obtained using 5% Ag/(Ag + Cu). The antibacterial activity of the undoped and Ag-doped particles of CMTS obtained using 5% Ag/(Ag + Cu) against different strains of pathogenic bacteria was tested using the agar well diffusion method. These results showed a significant antibacterial activity of the Ag-doped CMTS particle, which was much higher than the undoped CMTS particles. These experimental findings may open new practices for the Ag-doped CMTS compound, especially the one obtained using 5% Ag/(Ag + Cu), in antibacterial application.

Physical Investigations of (Co, Mn) Co-Doped ZnO Nanocrystalline Films.

Undoped as well as (Co, Mn) co-doped Zinc oxides have been effectively developed on glass substrates, taking advantage of the spray pyrolysis procedure. The X-ray diffraction XRD as well as X-ray photoelectron spectroscopy (XPS) measurements have recognized a pure hexagonal wurtzite form of ZnO, and no other collateral phases such as MnO2 or CoO2 have been observed as a result of doping. The calculated values of the texture coefficient (TC) were between 0.15 and 5.14, indicating a dominant orientation along the (002) plane. The crystallite size (D) varies with the (Co, Mn) contents. The dislocation density (δ) as well as the residual microstrains increased after Co and Mn doping. Furthermore, the surface morphology of the films has been affected significantly by the Co and Mn incorporation, as shown by the scanning electron microscopy (SEM) investigation. The study of the optical properties exhibits a red shift of the band gap energy (Eg) with the (Co, Mn) co-doping. The magnetic measurements have shown that the undoped and (Co, Mn) co-doped ZnO thin films displayed room-temperature ferromagnetism (RTFM).