Influence of nature melanin on the structural, linear/nonlinear optical properties and electrical conduction mechanism of PVA/CMC/PPy blended polymers for optoelectronic applications

Polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) have been used as polymeric matrices to create polymeric nanocomposite films that contain polypyrrole (PPY) and melanin as fillers. The structure of the PVA/CMC/PPy/x wt % melanin blends was analyzed using the X-ray diffraction technique. The scanning electron microscopy technique was used to investigate the morphologies of the blends. The highest absorbance and reflectance spectra were observed when the melanin content reached 0.25 and 0.2 % wt %, respectively. The smallest direct and indirect optical band gaps are (4.91, 4.44) eV and (4.22, 3.79, 2.34) eV, respectively, achieved when the melanin content was 0.25 wt%. The blend doped with 0.15 wt% PANi yielded the highest refractive index values (1.396 at λ = 600 nm). The optical dielectric constant values of the blends exhibited irregular improvement when the PVA/CMC/PPy blended polymer was filled with varying quantities of melanin. The blend doped with 0.15 wt% melanin exhibits the highest optical conductivity values in the visible range. The blend of PVA/CMC/PPy with a melanin concentration of 0.15 or 0.2 wt% demonstrated the highest nonlinear optical parameters. The blend of PVA/CMC/PPy with a melanin concentration of 0.15 or 0.2 wt% demonstrated the highest nonlinear optical parameter. Based on the observed behavior of the I-V characteristic, the possibility of ohmic conduct ions or space charge limited conduct ions is ruled out in all blends. The charge transport mechanisms that take place in different blends under varying temperatures were examined. These outcomes suggest the opportunity of employing the created blended polymer in capacitive energy storage, optoelectronic devices and photocatalytic application.