Influence of gamma irradiation on linear and nonlinear optical properties of nanocrystalline manganese(III) chloride tetraphenylporphine thin films.

ABSTRACT

90 nm thickness of MnTPPCl thin films were deposited by thermal evaporation technique on glass and quartz substrates under vacuum. The examined thin films were irradiated by 60Co γ-rays with 150 kGy. XRD and FTIR techniques are used to comprehend the structure of MnTPPCl thin films. The results confirmed that the structure of pristine thin films is nanocrystallites dispersed in the amorphous matrix and the irradiated films have an amorphous structure. Refractive index, oscillator's parameters (dispersion energy, Ed, oscillator energy, Eo), the absorption coefficient, optical energy gap, and Urbach energy were estimated before and after exposure to γ-irradiation by using spectrophotometric measurements. All mentioned parameters were influenced by the γ-irradiation process. The type of electronic transition was classified as a direct allowed transition. The gamma irradiation process was caused an increase in the fundamental band gap energy from 2.48 to 2.52 eV (blue shift) which is good for solar cells window. Third-order nonlinear optical susceptibility χ(3) and the nonlinear refractive index n2 of MnTPPCl thin films were studied before and after γ-irradiation. An increase in χ(3) and n2 with γ-irradiation is observed, so it is recommended to be used as optical switching applications.