<p>This study utilized the spray pyrolysis technique to fabricate KVO₃ layers of varying thicknesses at 230&#xa0;°C. The X-ray analysis of the KVO₃ layers indicated that these layers exhibit a polycrystalline structure through an orthorhombic phase. The EDX spectrum of the KVO₃ layers confirmed the presence of K, V, and O peaks at their respective energy levels, thereby validating the presence of stoichiometric components. The microstructural results indicate that the increase in film thickness increased the crystallite size of the as-prepared KVO₃ layers from 31.36 to 66.48&#xa0;nm while reducing the dislocation density and lattice strain of the investigated KVO₃ layers. The transmittance data for the KVO₃ layers demonstrated transmittance values exceeding 85%, which decreased with increasing thickness. The absorption coefficient analysis indicated a direct energy gap that decreased from 3.25 to 2.61 eV as the thickness of the KVO₃ layers increased. Furthermore, the optoelectrical parameters, including the values of optical dielectric constant, plasma frequency, electrical conductivity, and optical carrier concentration, were improved. The study of nonlinear optical characteristics of the KVO₃ layers refers to enhancing the nonlinear optical constants of the KVO₃ samples by increasing the thickness. Meanwhile, the hot probe procedure validated that KVO₃ layers exhibit n-type semiconducting characteristics. The results indicate that KVO₃ layers may serve effectively as a window layer for solar cells and as a viable option in optoelectronic applications. The ITO/KVO₃/Cu₂O/Al heterojunction was fabricated. This heterojunction device exhibits a solar conversion efficiency of 1.7%. The findings indicated that these KVO₃ samples may serve as a novel window layer.</p>