Performances of effective medium model in interpreting optical properties of polyvinylcarbazole:ZnSe nanocomposites

Abstract

The effective medium model is applied to investigate the optical properties of hybrid nanocomposite layers of Polyvinylcarbazole (PVK) and nanoparticles of Zinc Selenide (ZnSe). Thin films of PVK:ZnSe nanocomposites show a porous microstructure with pore diameters of 500 nm. Numerical calculations led to the determination of optical constants such as the refractive index n, the extinction coefficient k, the dielectric permittivity ε, and absorption coefficient α. Using common theoretical models, we have determined the Cauchy parameters of the refractive index, namely, static εs and lattice ε∞ dielectric constants as well as the plasma frequency ωp, carrier density to effective mass ratio Nme*, and the optical conductivity σoc. We show that the optical band gap energy Eg of the nanocomposite structure decreases slightly upon the increase of the nanoparticles volume fraction and is in good agreement with the Vegard law.