Optical absorption and linear/nonlinear parameters of polyvinyl alcohol films doped by fullerene

Abstract

New polymeric films were developed for optoelectronic devices by an interaction between Fullerene (C60) and polyvinyl alcohol (PVALC) via the casting method. The structure analysis was studied by Gaussian fitting of XRD patterns and SAED (Selected area electron diffraction). Using HRTEM and SEM, the particle shape and the nanocomposite surface on PVALC are investigated. The change in the functional group of the composites was observed via FT-IR and Raman spectroscopy. In this work, we calculated the bandgap and localized state's width, in the forbidden band, via the absorption coefficient obtained from the Beer-Lambert relation. The bandgap of nanocomposite films was reduced to 4.05 eV. Moreover, due to the surface plasmon absorption in nanocomposite films, k (Extinction index) increases with the doping concentration. The bandgap and refractive index (n) relations were studied via various empirical formulas to calculate the average value of n. The linear optical parameters, such as 1st-order susceptibility (χ(1)), high-frequency dielectric (e∞), and static dielectric (eo) constants, were calculated. The nonlinear susceptibility χ(3) raised from 0.928 × 10−12 esu to 1.779 × 10−12 esu. Also, the refractive index (n2) enhanced from 1.665 × 10−11 esu to 2.993 × 10−11 esu. The optical limiting performance and the ability of nanocomposite to absorb laser beams were tested. The result suggests that C60 has a considerable effect on the PVALC matrix, and the samples have the necessary guidance for laser CUT-OFF and photonic applications.