Multifunctional Applications of a Novel Ru-Metal Mixed PVAL Flexible Composite for Limiting Absorption and Varistor: Synthesis, Optical, and Electrical Characterization

Composite films with vital multifunctional properties for optoelectronic and varistor applications were prepared via casting procedures. Herein, the present novel composites are based on semi-crystalline polyvinyl alcohol, PVAL, mixed with different contents of Ruthenium-metal. The structure of the films has been fully identified through Fourier Transform (FT-IR), diffraction analysis of X-ray (XRD), and microscopy of scanning electron (SEM). They confirm significant interactions between Ru-metal and PVAL, which leads to a decrease in polymer crystallinity. Ru-metal’s impact on the optical performance has been studied using spectroscopy of UV–Vis–NIR, whereas the applicability of these films for varistor devices was investigated by measuring the electrical conductivity and I–V curves. The crystallite length (D), the spacing of interplanar (d), dislocation density (δ), internal strain (ε), and separation of interchain (R) parameters were calculated from the measurement of XRD. The active absorption band in FTIR spectra shows a significant interaction of Ru-metal with the PVAL via OH groups. The cluster of metal on the composite surface increases with the doping concentration, as illustrated via SEM. Optical bandgaps (E_gi & E_gd) are estimated from Tauc and absorption fitting (ASF) are nearly equal and reduced with ruthenium addition. Limiting optical absorption (LOA) performance tested using two laser sources showing the reduction of optical transmission via high doping concentration films. With rising Ru-metal content and frequency, the dielectric and AC conductivity tends to be enhanced. Also, the I-V characteristic was improved, and the conductivity follows the fitting of Jonscher. The collected result reflects the consideration of flexible Ru/PVAL as a promising polymeric film in varistor, micro-optics, optical fibers, and CUT-OFF laser applications.