Tailoring the linear and nonlinear optical characteristics of PVA/PVP polymeric blend using Co0.9Cu0.1S nanoparticles for optical and photonic applications

In this work, the linear and nonlinear optical characteristics of polyvinyl alcohol/polyvinyl pyrrolidone (PVA/ PVP) polymeric blend have been tailored via Co0.9Cu0.1S nanoparticles (CCS NPs) incorporation. Plain PVA/PVP polymeric blend and different (0.1, 0.5, 1.0, 5.0 and 10.0) wt% of Co0.9Cu0.1S NPs polymeric nanocomposites (PNCs) were prepared by solution casting technique. The samples' surface morphology, structures' variation, linear and nonlinear optical characteristics were explored using scanning electron microscopy, Fourier transform infrared (FT-IR) and UV-Vis-NIR spectrophotometry respectively. The FT-IR spectra analysis exposes the successful interaction and complexation of the CCS NPs with the host blend structure. The UV-Vis-NIR spectra analysis shows that the direct and indirect optical energy bandgap (Eg) of the host blend decreases from 5.15 eV to 4.94 eV-3.86 eV and 3.05 eV (10.0 wt% of CCS PNC) respectively. The Urbach energy of the plain blend increases from 0.41 eV to 1.18 eV (10.0 wt% of CCS PNC), which reveals the increase of the defects density due to CCS NPs incorporation. Also, the refractive index (n), dielectric constants (real epsilon r and imaginary epsilon i), optical conductivity, linear optical susceptibility (chi((1))), third-order nonlinear optical susceptibility (chi(3)) and nonlinear refractive index (n(2)) of the PVA/PVP blend are greatly enhanced due to CCS incorporation. The enhancement in the linear and nonlinear optical performance of the plain PVA/PVP blend via Co0.9Cu0.1S NPs incorporation nominates their applications in various optical and photonic devices.