The Preparation And The Effect Of Impurities On The Properties Of Lead Titanate Thin Films And Powders

The development of research on perovskite materials doped with ions and particles, sol-gel technique and sol-gel processing of PbTiO3 (PT) based materials were intensively reviewed. The luminescence theory of rare earth ions and the properties of carbon nanotube (CNT) were introduced briefly. According to the significant improvement in properties of ions and particles doped perovskite, Tb and CNT doped PT materials were prepared, and theproperties studied.Tb and CNT doped PT powders and films were successfully prepared by sol-gel method.By differential thermal analysis (DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), fluorescent analysis and dielectric constant analysis, the morphology and phase transformation, crystalline properties, fluorescent properties and dielectric properties of the materials were studied. And PbO single crystal nanowire was successfully prepared with new method.The results show that the amorphous matrix of the powders almost completely transforms into crystalline perovskite phase after 600 calcinations. The mean grain size in PT/Tb powder is about 23nm that is smaller than that of PT powders. Tb substitution of Pb induces lattice aberrance. This not only lowers the crystallization ability, butAlowers the tetragonality of the powders as well. It seems that a pseudo cubic phase was formed. The pyrochlore phase is effectively restrained in PT/Tb powders. Fluorescent properties of PT/Tb sol and powders were investigated. The fluorescence intensity of Tb observed in PT/Tb sol was stronger than that in powders. The network madeof O, Ti, such as sol and noncrystalline powders, determined the fluorescence intensity of Pb.The fluorescence intensity of Pb became weak when the crystal phase began to form in thathe lattice vibration absorbed the energy induced by the fluorescent transition.Tb doped PT thin films with highly (100) orientation were prepared. Rapid Thermal Annealing process was used to supply enough energy for the movement of the atoms. So perovskite phase began to form at (100) orientation which had the lowest surface energy. It shows that the interface energy and the heterogeneous nucleation barrier were changed by thedoping of Tb. So the relationship between crystal content and Tb doped concentration can be 'described as:y = 1 - exp(K1 exp(k cos( (x + )3)It shows that the crystal content will reach a maximum with increasing Tb dopedconcentration because of the influence of heterogeneous nucleation barrier variation.The dielectric constants of PT/Tb films were influenced by the lattice aberrance and crystal content. The dielectric constants were relatively high either lattice aberrance was tiny or crystal content was large.The synthesis of a single-crystal, ultra-long, uniform lead oxide nanowires were observed in a high vacuum chamber with the electron beam bombard in the Tb doped PT thin films derived from sol-gel process. With this method, single crystal lead oxide nanowires up to 600 nm in length were made.Sol-gel derived MCNT(mutiwall carbon nanotube) doped PT films and PLT were prepared. The content of MCNT in PT can be stabilized by controlling the viscosity of sol. The seemingly MCNT content in PT can be controlled by repeating the coatings of the film and increasing the MCNT doped concentration of the sol. The heterogeneous nucleation at the interface between MCNT and PT was induced by the doption of MCNT. The films which were calcined at 500 癈 had formed perovskite and large crystal content, means that perovskite formed at the lower temperature,In conclusion, the crystalline ability of PT was improved by the doption of Tb andMCNT. And the highly (100) oriented PT/Tb films was successfully prepared, the orientationmechanism can be-bfeadened-to the appirea|i other oriented films pfePT/Tb thin films as raw materials, the single-crystal, ultra-long, uniform lead oxide nanowires were successfully prepared w...