Effect of Er substituting sites on upconversion luminescence of Er3+-doped BaTiO3 films
(State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials,
Southwest University of Science and Technology, Mianyang 621010, China)
Southwest University of Science and Technology, Mianyang 621010, China)
Abstract: Erbium-doped BaTiO3 films on LaNiO3/Si substrates were fabricated by sol−gel method. The crystalline structure, morphologies and upconversion (UC) luminescence properties of films were respectively investigated by X-ray diffraction (XRD), atomic force microcopy (AFM) and photoluminescence (PL). The results indicate that both of the microstructure and luminescence are found to be dependent on Er3+ substituting sites. The samples with A-site substitution have smaller lattice constants, larger grains and smoother surface than those with B-site substitution. The photoluminescence spectra show that both of the samples have two stronger green emission bands centered at 528 and 548 nm and a weak red emission band centered at 673 nm, which correspond to the relaxation of Er3+ from 2H11/2, 4S3/2, and 4F9/2 levels to the ground level 4I15/2, respectively. Compared with B-site doped films, A-site doped films have a stronger integrated intensity of green emissions and a weaker relative intensity of red emissions. The differences could be explained by the crystalline quality and cross relaxation (CR) process.
Key words: Er3+ doping; BaTiO3 thin films; upconversion photoluminescence; sol−gel method