Comparable optical properties and dispersion parameters of monomeric axial ruthenium phthalocyanine thin films

Abstract

The ruthenium phthalocyanine complex [(n-hexyl)8PcRu] (2) and their derivatives [(n-hexyl)8PcRu(t-buNC)2] (3) and [(n-hexyl)8PcRu(Mepyr)2] (4) have been synthesized and characterized. The optical properties of their films have been studied by spectrophotometer measurements of transmittance and reflectance at normal incidence of light in the spectral range of 200-2500 nm. Absorption spectra of the films showed B and C absorption bands in the UV region followed by a Q-band in the visible region. The absorption parameters such as molar extinction coefficient, oscillator strength and electric dipole strength have been reported. The type of electronic transition is determined from an analysis of the absorption coefficient and found to be indirect allowed transition with onset energy gap and optical energy gap. The single oscillator model has been applied to calculate the dispersion parameters. The oscillator energy, the dispersion energy, the high frequency dielectric constant, the lattice dielectric constant and the ratio of free charge carriers concentration to their effective mass were evaluated. The dielectric properties of the films were also determined, showing that peripheral and axial ligand substituents on the complexes have a significant effect on their surface coverage. © 2013 Elsevier B.V.