Support‐Free CdS Films from Electrospun PVP/CdCl ₂ Composite Fibers: (1) Exposure to Na ₂ S Solution Surface and (2) Gas–Solid Reaction with H ₂ S Gas Followed by Exposure to Water Surface

Abstract This work explores new pathways to obtain CdS semiconductor films capable of covering almost any kind of solid substrate. Water‐soluble polyvinylpyrrolidone (PVP) was used to prepare fibers of PVP/CdCl 2 and PVP/CdS composite materials, which are later dissolved to obtain support‐free CdS films on an aqueous surface, which can be collected thereafter with the desired substrate. The PVP/CdCl 2 fibers were produced by electrospinning, and the subsequent treatments for CdS formation followed two distinct routs: (1) a direct reaction between the electrospun PVP/CdCl 2 and a 0.10 M Na 2 S solution to produce a CdS film on the solution surface, and (2) a gas–solid reaction between PVP/CdCl 2 and H 2 S gas to form PVP/CdS, which is later exposed to distilled water to release the CdS from the PVP matrix. The CdS films produced from PVP/CdCl 2 and PVP/CdS treatments were characterized chemically, morphologically, structurally, and optically. X‐ray photoelectron spectroscopy results demonstrated the successful synthesis of CdS material by means of the two described pathways. According to energy dispersive X‐ray spectroscopy and X‐ray diffraction, in both cases the CdS was sulfur deficient and ordered in the hexagonal structure. Energy bandgap values of the CdS films obtained from PVP/CdCl 2 and PVP/CdS were 2.38 and 2.39 eV, respectively.