Structural, Optical, and Opto‐Electrical Properties of PVA ‐ PVP : Sn Blend Films for Optoelectronic Applications

PVA‐PVP polymer blend films doped with varying concentrations of Sn were prepared using the solution casting method. X‐ray diffraction profiles of PVA‐PVP indicate that low Sn content exhibits a semicrystalline nature, whereas at higher concentrations, it transitions to an amorphous nature. The incorporation of Sn ions with the CO groups of PVP and the –OH groups of PVA serves as pseudo‐crosslinking centers, resulting in a reduction in the crystallinity of the films. SEM images reveal a homogeneous morphology with uniformly dispersed Sn ions. Increasing Sn concentration in PVA‐PVP reduces the optical band gap from 3.85 to 3.57 eV and enhances the refractive index because of the high polarizability of Sn 2+ . Optical dispersion parameters were evaluated using the Wemple–DiDomenico model. The linear and nonlinear optical parameters, including optical susceptibility ( χ (1) ), nonlinear refractive index ( n 2 ), third‐order optical susceptibility ( χ (3) ), and nonlinear absorption coefficient ( β c ) have been reported. The Sn dopant in PVA‐PVP introduces localized states that enhance charge‐transfer transitions, thereby improving both the linear and nonlinear optical responses of the films.