In this study the effect of annealing at 400oC and gamma irradiation at 30 kGy doses with the rate of 2.4 Gy/s as post treatments on optical properties and dimension of Ag nanoclusters were investigated. Ag nanoclusters were formed by ion-exchange process during which SLS substrates immersed in to the AgNO3 salt bath at 400oC. Grazing incidence x-ray diffraction analysis demonstrated the presence of Ag on Ag-ion exchanged substrates. The ion-exchanged substrates were then annealed and gamma irradiated as post treatments. The effect of post treatments on optical properties of samples including absorption spectra and linear refractive index, examined by analyzing optical density as a function of wavelength curves and Brewster angle determination. The results of absorption spectra indicated broadening and shift of ionic (Ag+N), and neutral (Ag0N) silver nanocluster peaks after post treatments. It was revealed about peak displacement as blue shift in annealed and red shift in gamma irradiated samples. Calculation of Ag nanocluster dimensions and refractive index of substrates revealed that post treatments procedures and especially gamma irradiation process caused non linear reduction in both of their values. However the linear refractive index of ion-exchanged and subsequently post treatments caused increase of linear refractive index of SLS substrate (n≈1.5).
Keywords: Ag nanocluster, gamma ray, Ion-exchange, linear refractive index, optical absorption spectroscopy.
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