Boosting the structural, electrical properties, and optical features of porous starch/poly(ethylene oxide) reinforced with NiMoO4 nanocrystals

Abstract

Synthesizing and characterizing novel flexible polymeric bio-nanocomposites for advanced applications in the medical, optoelectronic, and energy sectors has become an interesting topic of research worldwide. This work reports the influence of nickel molybdenum oxide nanocrystals (NiMoO₄ NC) on the structure, electrical features, and optical factors of a starch/polyethylene oxide (St/PEO) blend. The analyses carried out by the transmission electron microscope X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and FTIR techniques displayed that the sol–gel prepared NiMoO₄ composed of nanoparticles/nanorods, crystallized in a monoclinic structure with high purity. XRD, FTIR, and scanning electron microscopy, field-emission mode, (FE-SEM) showed that the semi-crystalline and porous structure of the nanocomposites was influenced by the uniform filler distribution. The effect of NiMoO₄ NC level on the dielectric permittivity, loss factor, and ac conductivity of St/PEO was studied under heating, and at frequencies up to 7 MHz. Moreover, various optical factors (transmittance in the UV–vis-NIR wavelengths, extinction coefficient, band gap, optical-dielectric loss, and index of refraction (n)) were also evaluated and discussed. The films displayed dual direct/indirect \({\text{band gaps }E}_{g}^{op}\). The direct (indirect) \({E}_{g}^{op}\) narrowed from 4.8 to 4.3 eV (3.9 to 3.0 eV) for the high-energy region. NiMoO₄ NC changed the n behavior to a wave-like pattern with a significant increase to 3.5˗5.0. The structural changes, as well as the related dielectric and optical enhancements, make NiMoO₄/St/PEO materials ideal candidate semiconductors for high refractive index and energy-storing applications.