Optical characterization of rubrene preparation thin films with spin coating method

In this thesis study, rubrene organic semiconductor thin films preparation by spin coating technique and optical characterization were aimed. The optical properties of rubrene thin film were investigated using a spectrophotometric measurement of transmittance and reflectance at normal incidence of light in the wavelength range 200?700 nm. The optical transmittance of the film was obtained ranging of 90?96% in the visible region. The type of optical transition near the edge of the band gap from optical absorption measurements is found to be indirect allowed transition. The onset optical and transport energy gaps were found to be 2.31 and 2.93 eV, respectively. Wemple-DiDomenico single oscillator model and single term Sellmeier dispersion relation were used to analyze the optical dispersion parameters. From the optical dielectric constants analysis, the loss tangent, the electric modulus, the optical conductivity, the volume and surface energy loss functions, and the relaxation time were also discussed. The third order of nonlinear polarizability parameter is found to be of the order 10-12 esu. Scanning electron microscopy (SEM) was also used to image the surface morphology of the prepared rubrene thin film. Key Words: Organic Semiconductors, Rubrene Thin Film, Transmittance, Absorption, Reflection Spectrum, Absorption Coefficient, Dipersion Parameters, Dielectric Properties.