Optical parameters of epoxy-CoSO4.7H2O polymer hybrid material

Epoxy-CoSO4.7H2O polymer hybrid films were prepared with various loading levels (from 0.28 wt% up to 5.00 wt%) of inorganic component (CoSO4.7H2O). UV-vis absorption spectra of these hybrid films, in the wavelength range starting from 200 nm up to 800 nm were analyzed to estimate their band gap. Interestingly, drastic reduction in the band gap was observed for hybrid film containing 0.56 wt% of CoSO4.7H2O, compared to pure epoxy film. Various optical parameters such as transmittance (T’), reflectance (R), absorption coefficient (α), extinction coefficient (k), refractive index (n), real and imaginary parts of optical dielectric constant (εr and εi), skin depth (δ) and optical conductivity (σ) for these films are determined and analyzed. Variation of εi with respect to energy is also employed to confirm the types of optical transitions in the material. Single oscillator model was also adopted to obtain various optical parameters of importance. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.