Exploration of spray pyrolysis technique in preparation of absorber material CFATS: Unprecedented hydrophilic surface and antibacterial properties

In this study, we achieve the production of nontoxic Cu2Fe1-xAlxSnS4 films (x = 0, 0.25, 0.50, 0.75 and 1) by substituting Fe with Al atoms. Physical properties of the investigated films were studied using: Energy dispersive X-ray spectrometry (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, spectrophotometer and drop shape analysis system (DSA). The formation of new quaternary Cu3Al0.6Sn1S6 (CATS) chalcogenide for x = 1 was proven from EDX study. Notably, the major diffraction peaks were located at 2θ = 28.34°, 47.43° and 55.93° which are respectively tagged as (1 1 2), (2 0 4), and (3 1 2) plans, confirming the stannite crystal structure of Cu3Al0.6Sn1S6 film. The morphological states show a nanofiber structure accompanied with voids and cavities for CATS films. Tauc-relation plot reveals direct energy bandgap, close to 1.52 eV, which proves the absorber film type of Cu3Al0.6Sn1S6. The effluent toxicity of the obtained thin films has been assessed using the inhibition of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and indicated good antibacterial activity of the CATS/SnO2:F heterojunction. The viability rates against S. aureus achieved 40 %, 31 % and 15% for SnO2:F, Cu3Al0.6Sn1S6 films and CATS/SnO2:F heterojunction. These results highlight the great antibacterial activity of coupled CATS/SnO2:F. Therefore this research underscores the effectiveness of CATS/SnO2:F surface which demonstrates self-disinfecting and self-cleaning with hydrophilicity and high antibacterial activity.