Preparation And Luminescence Properties Of Rare Earth/Bridged Polysilsesquioxane

Bridged polysilsesquioxane is a new class of organic/inorganic hybrid materials with special properties. RE/bridged polysilsesquioxane have excellent luminescent properties,So it has important significance and application value into rare earth functional materials. As follows contents have been studied in this paper:(1) We have synthesized three kinds of bridged monomers, bridged groups are piperazine, triazine, 2, 2'-bipyridine respectively. New luminescent bridged polysilsesquioxanes were prepared by hydrolysis and polycondensation of the bridged monomers in the presence of lanthanide ions.(2) The bridged polysilsesquioxanes exhibited characteristic red emission and green emission upon the addition of Eu³⁺ ions and Tb³⁺ ions respectively.(3) The Nd³⁺ doped bridged polysilsesquioxane containing piperazine group shows luminescence in the near-infrared regions. In addition, the number of water molecules in the first coordination sphere of Eu³⁺ ions has been calculated on the basis of emission spectrum and lifetime of 5D0 state. The Tb³⁺ doped bridged polysilsesquioxane containing piperazine group is the longest lifetime in sol-gel-derived organic-inorganic hybrid material so far. FT-IR spectra and luminescence spectra confirm the coordination of Eu³⁺ (Tb³⁺) ions to the C=O groups.(4) The predicted structure of bridged polysilsesquioxane containing triazine group was given based on the FT-IR analysis, luminescence spectra and data from reference.(5) The luminescent intensity for Eu(TTA)₃·2H₂O doped bridged polysilsesquioxane containing 2, 2'-bipyridine group is much stronger than Eu³⁺ doped bridged polysilsesquioxane containing 2, 2'-bipyridine group. This suggests that Eu(TTA)3·2H2O was bound to the 2, 2'- bipyridine groups on the silica gel and the coordinated water was expelled. The predicted structure of bridged polysilsesquioxane containing 2, 2'-bipyridine group and Eu(TTA)3·2H2O were given based on the FT-IR analysis, luminescence spectra and data from reference.