Exploring the optical properties of CuCo₂O₄-doped polyethylene oxide and carboxymethylcellulose for optoelectronic application

Nanocomposite films comprising polyethylene oxide (PEO) and carboxymethylcellulose (CMC) were fabricated via the solution casting process, with the incorporation of copper cobaltite nanoparticles (CuCo₂O₄ NPs). The study investigated the impact of CuCo₂O₄ NPs on the structural and optical properties of the PEO/CMC polymer blend, using X-ray diffraction, Fourier transform infrared (FTIR), and ultraviolet–visible spectroscopy (UV–Vis). The Debye–Scherrer equation was utilized to determine the size of the nanoparticles, and the results showed that the nanoparticle size decreased upon dispersion within the host matrix. The FTIR spectra of PEO/CMC blends revealed distinct vibrational spectral bands. These bands exhibited variations in their intensities, signifying interactions attributed to hydrogen bonds in the polymers. Various optical parameters, including energy gap, refractive index, Urbach energy, and extinction coefficient, were examined. The transmittance of the PEO/CMC blend exhibited a decrease from 88.6 to 18.8% following the dispersion of 3 wt% CuCo₂O₄ NPs. The optical analysis revealed an increase in the refractive index and a reduction in the optical band gap values, which reduced from 4.37 eV in the polymer blend to 3.77 eV in samples containing 3 wt% CuCo₂O₄. Furthermore, an increase in Urbach energy was observed with the rise in CuCo₂O₄ NPs content. The study also explored the influence of CuCo₂O₄ NPs on the fluorescence spectra of the PEO/CMC matrix and observed an increase in both optical dielectric and optical conductivity with increasing CuCo₂O₄ NPs content.