查看文章

We have studied and compared the optical properties of SrAl_1.7B_0.3O₄:Eu, R (R=Nd, Dy) pigments that present long-lasting phosphorescence obtained by different synthesis techniques. Samples obtained by ceramic methods, in our laboratories and by an industrial process, present better phosphorescent properties than those obtained by sol–gel technique. Raman spectra show that grinding produces severe damage of the lattice. We have obtained and analyzed the Eu³⁺ crystal field luminescence indicating that Eu³⁺ is found in quite different sites comparing ceramic and sol–gel samples. Codoping, with Nd or Dy is necessary in order to reduce the Eu³⁺ content, in all cases. The green luminescence band, obtained under UV illumination, can be fitted to two and three components in ceramic and sol–gel samples, respectively, due to different Eu²⁺ sites. Eu–Dy samples present the longest and the most efficient …