Nonlinear behavior of the current-voltage characteristics for erbium-doped PVA polymeric composite films

The universal casting method for an aqueous solution has been used to synthesize PVA solid samples with 0, 0.037, 0.37, 3.7, 18.5, and 37wt% of Er3+-ions. The semi-crystalline nature of solid films was proved by analyzing the pattern of the XRD, while the complex formation has been confirmed via FTIR spectroscopy. SEM shows the formation of clusters oftheEr(3+)-ions on the superficiality of PVA. The optical parameters, dielectric permittivity, and I-V characteristics have been studied. The incident light is completely absorbed in UV-region by PVA: 37wt% Er3+-sample. Moreover, the indirect energy,E-g1, gap decreased from 4.98 to 4.74eV, whereas the index of refraction increased from 1.53 to 2.85 with Er3+-ions concentration. Dielectric permittivity decreases with a high proportion of Er3+-ions in PVA and an interesting nonlinear behavior of I-V characteristics is observed in PVA: 37wt% Er3+-sample. The characteristics of synthesized materials revealed that it can be used for manufacturing cheaper varistor device, UV-protector, and optoelectronic applications.