Preparation And Properties Of Rare Earth/Bridged Polysilsesquioxane

Rare earth complexes possess the advantages of high quantum efficiency,high color purity,long lifetimes and rich spectrum lines.However,they have been excluded from optical field and other fields due to their poor thermal stabilities and low mechanical strength.To solve this problem,a new type of hybrid materials is concerned,namely the bridged Polysilsesquioxane(BPS).This kind of materials combines the characteristics of both organic and inorganic components,which makes its application range increase.Another kind of materials called cyclodextrin inclusion has also aroused people's interest.Cyclodextrin(CD)whose inner cavity is hydrophobic and outer wall is hydrophilic,as the host molecule,can package a variety of guest molecules to form inclusions.In this article,?-cyclodextrin(?-CD)and BPS were combined to prepare rare earth hybrid luminescent materials and study their properties.The main contents are as follows:(1)The raw material pyromellitic acid was prepared into pyromellitic acid chloride,which was modified by(3-aminopropyl)triethoxysilane(APTES),and coordinated with rare earth ions.The binary rare earth/ pyromellitic acid bridged polysilsesquioxane with three dimensional network structure was synthesized by the method of sol-gel.The second ligand 1,10-Phenanthrolinemonohydrate(Phen)was introduced to produce ternary hybrid materials.The four hybrid materials was characterized,the result of which showed that the hybrid materials had excellent thermal stabilities as well as high mechanical strength,and that the luminescent intensity and lifetimes of ternary hybrid materials were higher than those of binary hybrid materials.(2)The ?-CD was chosen as the host molecule and modified by TESPIC.The modified ?-CD was reacted with ?-Thenoyltrifluoroacetone(TTA)coordinated with europium ion.The ternary hybrid materials were synthesized by the introduction of Phen and PMA respectively.The modified hybrid material ?-CD-TESPIC-TTA-Eu possessed homogeneous structure,higher luminescent intensity and longer lifetime compared with ?-CD-TTA-Eu inclusion.However,properties of ternary hybrid materials with the second ligands weren't as good as the modified binary hybrid materials.(3)?-CD-Coumarin-Eu inclusion was prepared by ?-CD as the host molecule and coumarin as the guest molecule.Then Phen and PMA as the second ligands were respectively added to the system to synthesize the corresponding europium inclusions.?-CD modified by TESPIC was reacted with coumarin,Phen and PMA respectively to form two kinds of modified hybrid materials.The luminescent intensity,lifetime and homogeneity of ?-CDCoumarin-Phen-Eu improved greatly.In the two types of modified materials,the hybrid materials introduced by PMA had higher thermal stability,longer lifetime and excellent homogeneity.