Influence of γ-irradiation on the optical parameters of 4-tricyanovinyl-N,N-diethylaniline thin films

Thin films of 4-tricyanovinyl-N,N-diethylaniline (TCVA) were prepared by thermal evaporation technique. The spectral and the optical parameters have been investigated by using the spectrophotometric measurements of both transmittance and reflectance at normal incidence of light in the wavelength range 200–2500 nm. The effect of γ-irradiation on the optical parameters was investigated. It was observed that the increase in γ-irradiation dose caused an increase in the value of absorption index and a shift in the spectrum towards higher wavelengths. Therefore, the value of the optical band gap has decreased from 1.45 eV for as-deposited film to 1.39 eV for film exposed to γ-ray dose of 150 kGy and Urbach tail increased. On the other hand, the dispersion parameters of TCVA films were increased with the increase of the irradiation dose.