Study On Preparation And Properties Of Nano-ZnO And ZnO/RE Particles

ZnO is one of the most attractive functional semiconductor materials. It has a wide band gap(3.37 eV) and a high exciton binding energy (60 meV) at room temperature. Due to its good optoelectronic properties, it can be widely applied in the fields of room-temperature ultraviolet lasing, sensor and photocatalysis etc. ZnO has many intrinsic point defects such as oxygen vacancy and zinc interstitial atom. Doping to ZnO is one of the methods to improve its performance.La-doped ZnO was synthesized by hydrothermal method. The effect of pH, doping content and reaction time on the size and morphology of the particles was evaluated. The products were characterized by XRD, SEM, EDS and UV-Vis. The results indicated that the growth of ZnO crystals was inhibited during the doping process. The ZnO/La₂O₃ composite powders with size of 20～40 nm were obtained; As the radius of La³⁺ is bigger than that of Zn²⁺, the doping with La into ZnO crystal lattice caused the distortion of lattice and the change of lattice parameters; The photocatalysis properties of ZnO were improved when the doping content was 3%.ZnO composite powers doped with La, Y and Nd were prepared by polymer network method. The influence of doping content and sintering temperature on the particles size and morphology was discussed. The samples were characterized by XRD, SEM, TEM, EDS and FT-IR. The results showed that the doping with La, Y and Nd can suppress the growth of ZnO, the particle size of the composite particles decreased with the increase of doping content, whereas the size increased with the increase of sintering temperature.ZnO nanometer powders were prepared by microwave method and microwave-hydrothermal method, the influence of pH on the size and morphology of the particles prepared by microwave-hydrothermal method and traditional hydrothermal method was studied. The characterization of the products by XRD and SEM showed that the microwave method had the advantage of energy saving and high efficiency during the reaction, and might directly synthesize homogenous morphology nanoparticle with the size of 37.8 nm.conducting composite materials were fabricated by using polyaniline to modify the surface of ZnO, ZnO/La₂O₃, ZnO/Y₂O₃ and ZnO/Nd₂O₃. The samples were characterized by XRD and SEM. The conductivity of ZnO-PANI was measured by four probe electrical conductivity instrument and equal to 2.326 s·m^-1, which was one order higher than that of RE-doped ZnO.