Fourier-transform infrared and UV–vis spectroscopes of nickel phthalocyanine thin films

Abstract

The Fourier-transform infrared (FT-IR) technique has been applied to identify the polymorphs of phthalocyanine molecules. The infrared absorption (IR) spectra were recorded in the spectral range 400–1000 cm −1. A comparison of absorption spectra of powder, as-deposited and annealed films is presented. The powder absorption spectrum was identified as rich of β-NiPc, where the thermally deposited films at room temperature were identified as the rich of α-NiPc. Moreover, the main spectral peaks of the films, annealed at 573 K, were defined as rich of β-form. The absorption measurements recorded in the UV–vis region showed two well-defined absorption bands of phthalocyanine molecule, namely the Soret band (B) and the Q-band. The Q-band showed its characteristic splitting (Davydov splitting), and Δ Q was obtained as 0.21 eV. Some of the important optical absorption parameters such as the molar extinction coefficient, the oscillator strength, and the electric dipole strength have been evaluated.