Improved optical characteristics of PEO polymer integrated with graphene oxide

In this study, graphene oxide (GO) was synthesized via a modified low-temperature Hummer's method and incorporated into a poly (ethylene oxide) (PEO) matrix to fabricate PEO/GO nanocomposite thin films using a casting technique. This work explores how GO incorporation affects the structural and optical properties of PEO, with emphasis on its suitability for optical switching and other optoelectronic applications. The films were prepared with varying GO concentrations and characterized using XRD, UV–Vis spectroscopy, and other standard techniques. XRD confirmed successful GO incorporation by revealing intercalation-induced structural changes. Optical transmittance dropped from 88% (pure PEO) to 18% (7 wt% GO), demonstrating strong UV-blocking ability. UV–Vis analysis showed a red-shift in the absorption edge with increasing GO content, and Tauc's method indicated a reduction in the optical bandgap from 5.82 eV to 2.12 eV. Key optical constants improved significantly: the refractive index rose from 1.72 to 2.21, the absorption edge decreased from 5.63 to 2.27 eV, and the extinction coefficient increased with GO loading. Wemple–DiDomenico analysis revealed a decrease in dispersion energy (from 13 to 12.7 eV) and oscillator energy (from 6.52 to 3.29 eV). Nonlinear optical properties also improved, with third-order susceptibility increasing from 0.57 × 10⁻⁵ to 2.98 × 10⁻⁵ esu and nonlinear refractive index from 4.4 × 10⁻⁵ to 5.2 × 10⁻⁵ at 7 wt% GO. Drude model analysis showed a substantial rise in the carrier concentration-to-effective mass ratio from 1.50 × 10⁵⁴ to 11.58 × 10⁵⁴ m⁻³·kg⁻¹. These enhancements demonstrate that GO-doped PEO films are promising candidates for next-generation optical switching and optoelectronic devices.