Synthesis, optical, and electrical properties of starch/chitosan/NaTiO3 bio-nanocomposites modified with ErCl3

Solid polymer electrolytes (SPEs) based on nanocomposites are attracting increasing attention due to their technological and industrial applications. In the present work, a facile aqueous casting method was utilized for the preparation of a starch-chitosan blend loaded with nanosized NaTiO3 (NTO) and co-mixed with ErCl3 (EC) salt. The interactions between OH group of starch and N-H group of chitosan with NTO and EC, and the films' crystallinity and surface morphology were studied by FTIR, XRD, and SEM. UV-Vis-NIR measurements showed the indirect (direct) optical band gaps decreased from 3.4 to 2.0 eV (4.5 to similar to 2.5 eV), i.e., similar to 41%-44% shrinking. At the time that the films maintained a reasonable transmittance. The optical constants of the films; extinction coefficient, refractive index, and the carrier's concentration to the electron effective mass (N/m*) are reported. N/m* of the pure blend was 4.85 x 10(39) (kg(-1) m(-3)) increased to 1.64 times and 2.8 times after loading with 1.0% NTO and 20% EC, respectively. Various dielectric parameters (dielectric constant epsilon', dielectric loss epsilon '', ac conductivity sigma(ac), and dielectric moduli M'& M '') were evaluated in the frequency range 5Hz-1MHz and temperatures of 298-353 K. The conductivity (sigma(ac)) of the blend increased from 1.10 x 10(-3) S cm(-1) to 8.17 x 10(-3) S cm(-1) after modifying with 20% EC, i.e., became 8 times greater. Moreover, the influence of NTO and EC on the conduction mechanism and Cole-Cole plots are discussed. The improvements in the optical and electrical properties of EC/NTO/blend illustrate the possibility of extending the applications of these smart materials to include optoelectronic devices, batteries, and supercapacitors.