Study the effect of nano NiCo2O4 doping on the optical and dielectric properties of PMMA/PEO/MWCNTs

Abstract

In this study, NiCo2O4 nanoparticles were prepared using a hydrothermal process and examined by x-ray diffraction. After that, using the casting technique, blends of polymethyl methacrylate (PMMA)/poly(ethylene oxide) (PEO) were loaded with multi-walled carbon nanotubes (MWCNTs) and different amounts (x) of NiCo2O4 nanoparticles. The obtained blends were characterized using X-ray diffraction and scanning electron microscopy techniques. Utilizing diffuse reflectance measurements, various optical parameters, including energy gap, refractive index, extinction coefficient, optical dielectric constant, optical conductivity, and nonlinear optical parameters, were investigated. Following incorporation of MWCNTs/NiCo2O4 in the blend, the transmittance of the PMMA/PEO blend (90 %) displayed a drop reaching 21 %, the reflectivity and refractive index increased. The direct/indirect optical band gap values of PMMA/PEO (5.07/4.8 eV) decreased attaining 4.96/4.54 eV for the blend with 2.5 wt% NiCo2O4. The optical conductivity greatly enhanced, and the linear and nonlinear optical parameters increased as the amount of NiCo2O4 doping increased. The dispersion parameters for all blends were also calculated. Fluorescence spectra (FL) measurements revealed a reduction in the FL intensity with increasing the NiCo2O4 content (x). Through the dielectric measurements, the impact of increasing NiCo2O4 content on the ac conductivity, dielectric properties, energy density, and electric modulus was analyzed for all blends. Remarkably, a significant increase in AC conductivity was obtained upon loading with 1.5 wt% NiCo2O4. Overall, variation in the dielectric and optical features of the PMMA/PEO/MWCNTs/x wt.% NiCo2O4 blends makes them appropriate for optoelectronic and energy storage applications.