Structural and optical properties of iron (III) chloride tetraphenylporphyrin thin films

Abstract

Iron (III) chloride tetraphenylporphyrin (FeTPPCl) thin films are prepared on quartz and glass substrates at room temperature by thermal evaporation technique. The X-ray diffraction showed the amorphous nature for both the as-deposited and the annealed films at 423 K in air for 2 h, whereas the powder has the tetragonal form with lattice constants of a = 13.53 and c = 9.82 . The optical properties of FeTPPCl films are investigated using a spectrophotometric measurement of transmittance and reflectance at normal incidence of light in the wavelength range 190–2500 nm for the as-deposited and the annealed films. Absorption spectra of the films showed B, N and C absorption bands in the UV region followed by a Q-band in the visible region. The onset optical gap is determined from the analysis of the absorption coefficient values and found to be 1.53 eV for both the as-deposited and annealed films. The dispersion of the refractive index, n , is discussed in terms of Cauchy relation and the single oscillator model. The polarizability, the dispersion parameters, the ratio of free carrier concentration to the free carrier effective mass are also estimated.