Influence of X-ray irradiation on the optical properties of ruthenium(II)octa-(n-hexyl)-phthalocyanine thin film

Ruthenium(II)octa-(n-hexyl)-phthalocyanine [(n-hexyl)8PcRu] (2) thin films have been deposited on different substrates by thermal evaporation technique under high vacuum. X-ray diffraction (XRD) pattern of [(n-hexyl)8PcRu] (2) in the powder form indicated that it has polycrystalline form with a triclinic structure. The XRD results for [(n-hexyl)8PcRu] (2) thin films confirm the amorphous nature for the as-deposited films. The optical properties of [(n-hexyl)8PcRu] (2) were investigated for as-deposited and irradiated films using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in the wavelength range from 200 to 2500 nm. The recorded absorption measurements in the UV–vis region show two well defined absorption bands of phthalocyanine molecule; namely the Q-band and the Soret (B-band). The refractive index (n) and the absorption index (k) were calculated. According to the analysis of dispersion curves, the parameters, namely; the optical absorption coefficient (α), molar extinction coefficient (ɛmolar), oscillator energy (Eo), oscillator strength (f), and electric dipole strength (q2) were also evaluated. The analysis of the spectral behaviour of the absorption coefficient (α), in the absorption region revealed indirect transitions.