Characterization and optical properties of polymer nanocomposite films for optoelectronic applications

Polymer nanocomposite films combining polyaniline (PANI) and lead (II) sulfide (PbS) nanoparticles (PbSNPs) were effectively synthesized using a casting solution approach for use in optical energy applications. Transmission electron microscopy, X-ray diffraction and infrared spectroscopy showed that PbSNPs were successfully introduced into the PANI matrix. Scanning electron microscopy images revealed that lead (II) sulfide was homogenously loaded and distributed in the PANI chain. Using ultraviolet–visible optical absorbance, the optical parameters of PANI/PbSNPs were evaluated, including absorption edge (E _d), bandgap (E _g), carbon cluster number (N) and Urbach energies (E _u). PbSNPs were investigated for their impact on PANI polymer linear optical as well as non-linear optical characteristics, including refractive index, non-linear susceptibility and dielectric parameter. When comparing the PANI/PbSNP film to the pure PANI film, the bandgap of the PANI/PbSNP samples was found to be reduced significantly. However, the addition of PbSNPs increased the predicted value of optical conductivity and the carbon cluster number. The addition of PbSNPs to the PANI polymer improved its optical characteristics, resulting in a synthetic composite that can be used in energy applications as well as optoelectronic devices.