Boosting the structural, optical, and dielectric properties of a polyvinyl polymer by hematite NPs and DPC addition: Nanocomposites for optoelectronics and microelectronic devices

This work studies the reinforcing influence of hematite nanoparticles ( α -Fe 2 O 3 NPs) and the addition of 1,5-Diphenylcarbazide (DPC) on the structural, band structure, and dielectric features of a polyvinyl chloride (PVC)-polyvinyl acetate mixed matrix. Hexagonal α -Fe 2 O 3 NPs, 18 nm in size, were prepared by a facile and cost-effective chemical method. XRD spectra indicated the alteration of the amorphous nature of the matrix upon loading α -Fe 2 O 3 NPs and DPC addition. FTIR, SEM, and EDX analyses showed the (physical) interaction and complexation between the additives and matrix functional groups. UV-vis-NIR analyses revealed the decrease in the matrix transmittance from 82% to 34% upon loading α -Fe 2 O 3 NPs. In addition, the co-addition of DPC prohibited any transmittance below 660 nm. Moreover, there is a reduction in the direct/indirect band gaps from 4.2/4.0 eV of the matrix to 4.15/3.9 eV for α -Fe 2 O 3 /matrix, then to 3.0/2.0 eV upon the co-addition of DPC. The corresponding Urbach tail increased from 0.081 to 0.773 eV. Dielectric properties were investigated by applying frequencies from 10 2 to 8 × 10 6 Hz and temperatures from 300 to 410 K. The of the matrix at 10 2 Hz is in the range of 4.52−6.0, increased to 5.4−11.5 upon loading α -Fe 2 O 3 NPs. There is a strong correlation between DC conductivity and . The conduction mechanism in the films was governed by the correlated barrier hopping and the quantum mechanical tunnelling. The impacts of α -Fe 2 O 3 and DPC on the extinction coefficient, Urbach energy, dielectric modulus, energy density, and Cole-Cole profiles of the films are reported. The results indicate that DPC/ α -Fe 2 O 3 /matrix is the best for optical applications, while α -Fe 2 O 3 /matrix can be developed for supercapacitors.