Influence of Lanthanum on Fluorescence Properties of Ag-BaO Thin Films

【Abstract】 Ag BaO thin films doped with lanthanum were prepared by vacuum deposition. Compared with the normal Ag BaO thin film, there is almost no change with the shape and the peak site of the fluorescence spectrum; however, fluorescence emission strength of the whole observation band(325～600 nm)increases about 40%, and the increase of short wavelength range is more remarkable than that of long wavelength range, which we named “blue stronger” phenomenon. Analytic results show that, with the forming of intermetallic compounds between silver and lanthanum, the 4f state energy levels lie just below the Fermi level within 5 eV. It is the energy exchange between the 4f energy levels and the conduction band that causes the increase effect of fluorescence emission, and it is the optical absorption cross section of 4f electron, which increases with the increase of energy of incidence photon, that gives rise to the “blue stronger” phenomenon.更多还原