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 $\acute\AA$ and c = 9.82 $\acute\AA$. 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.