Spectroscopic characterization of natural dye derived from hybrid poplar waste leaves to enhance the optical characteristics of PVA biopolymer

C NMR spectroscopy were used to obtain insights about the functional groups that appeared in the HP dye. The PVGHPC films were prepared by a solution casting method. The XRD pattern verifies that the addition of HP dye reduces the crystalline phase of PVA. The UV-Vis study proves that there is an increase in absorbance, a decline in transmittance, and an increase in reflectance for PVGHPC films. It was found that incorporating HP dye into PVA results in a significant reduction in the optical band gap from 5.92 eV to 2.12 eV. The increase of the extinction coefficient and boost in refractive index establish that HP dye enriched the (PVGHPC) with a huge number of localized states ascribing to color centers. Improvement of optical dielectric parameters is attributed to an increase of charge carriers in the doped films. The volume energy loss function (VELF) and surface energy loss function (SELF) were examined for microscopic measurements. The HP dye is compared to several dyes that have distinct properties related to the reduction of the band gap process of the polymer composites.