Structure, Composition and Optical Properties of Thin Films of Copper Sulphide and Bismuth Sulphide Deposited on Various Textiles by the SILAR Method

The synthesis of thin films in multilayer structures on different textiles is of interest due to their potential use in flexible solar absorber coatings and thin-film solar cells. The aim of the study was to deposit bismuth(III) sulphide and copper(II) sulphide thin films on various textiles at the same time. This was achieved using the sustainable and cost-effective successive ionic layer adsorption and reaction (SILAR) method. The study examined how the elemental distribution, phase composition, crystallinity, surface morphology, and optical features of the resulting films are determined by the intrinsic structure and material makeup of structural textiles. The analysis used data from scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD), as well as ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy. Depending on the textiles used, the formed films were polycrystalline and rich in copper. According to the findings, the normalised atomic percentages were as follows: Cu, 57.66–68.75%; Bi, 1.19–5.26%; S, 30.06–38.63%. The direct transition optical energy gap values varied from 1.3 to 2.88 eV, while the indirect varied from 0.9 to 2.25 eV, and the refractive index from 1.3 to 1.8. These properties were influenced by the composition of the textiles and the films themselves. These properties directly impact the films’ applications.