Copper And Copper Oxidation Nanocrvstals; Synthesis, Properties And Applications

In the past decade, enormous efforts have been devoted to develop highly conductive inkmaterials to meet the needs of flexible electronics, such as conductive polymers, organo-metalliccompounds, metal precursors, and nanoscale metallic particles.2-D Cu nanostructure, inparticular, is a promising novel metal material alternative for conductive ink due to its low priceand high conductivity. To our knowledge, a few strategies have been developed to synthesis2-DCu nanostructures. An environment-friendly aqueous synthesis strategy still remains as achallenge, which can be capable of generating large-area2-D Cu nanosheets for conductive ink.Herein, a Cu nanocrystal self-assembly strategy was developed to prepare large-area Cunanosheet. Furthermore, heteronanostructures of Ag-nanoparticles coated Cu nanosheet wereachieved by a galvanic displacement reaction, which can improve the thermal stability andconductivity of the Cu nanosheets at high temperature. As a kind of typical p-type semiconductormaterial, cuprous oxide (Cu2O) can adsorb the visible light and arouse electrons. As we knowthat the morphology and structure of nanomaterials has an important influence on their propertiesand applications, therefore, to prepare controlled morphology of Cu2O has important significancein different applications.In this thesis, large-area Cu nanosheets are synthesized by a strategy of Cu nanocrystalself-assembly in a facle condition. The effects of different reaction parameters, such as time,copper salts and PVP, on the morphologies and structures of Cu nanosheets were studied. Andthe reasonable growth mechanism was proposed. In addition, different morphology of nanocuprous oxide particles were prepared by chemical reduction methods and different factor effectson its scrystal growth were studied. The results achieved in this paper were listed as follows:1. Large-area self-assembled Cu nanosheets were prepared by a facile hydrothermalapproach. The effects of different reaction parameters on the morphologies of Cu nanosheetswere studied, such as time, copper salts and PVP. Cu nanoparticles, as the building block, wereself-assembled along with the <111> direction to form large-area Cu nanosheets. Then, aqueousconductive Cu-nanosheet ink was successfully prepared for the conductive circuits on flexibleelectronics. The conductive ink based on copper nanosheets with good capability in writing, were able to print any shape of circuits. The laminar structure of nanosheet ciruits can maintainthe stability of the conductivity under stress, no cracks and open circuit phenomenon appeared.2. Copper nanosheets coated by silver nanoparticles have been prepared by galvanicdisplacement. The effects of different reaction solvent on the morphologies of Ag nanoparticleswere studied. In aqueous solution, silver nanoplates on the surface copper nanosheets wereobtained. In ethylene glycol solution, silver nanoparticles on the surface copper nanosheets wereobtained. Aqueous conductive silver nanoparticles coated copper nanosheets ink is successfullyprepared for the conductive circuits on flexible electronics. Based on copper nanosheets coatedby silver nanoparticles, conductive ink has a good writing capacibility on paper and the stabilityof conductance under crumpling. Loading on the surface and edges of Cu-nanosheets, Agnanoparticles can effectively improve the area of contact between the layers. Two materials havea good thermal stability at high temperature.3. Octahedral Cu2O nanocrysyals, cubic Cu2O nanocrystals, hollow spheres Cu2Onanoparticles and hollow cubic Cu2O nanoparticles were prepared by using simple chemicalreduction and hydrothermal methods. The growth mechanisms of different morphologies ofCu2O nanocrysyals were also studied. Charaterization and photochemical catalysis of differentmorphologies of Cu2O nanocrysatl were also investigated. Cu2O has good degradation efficiencyof organic dyes in visible light, and degradation rate of methyl orange order can be listed as:nano cuprous oxide octahedral> hollow ball morphology of nano cuprous oxide> hollow cubecuprous oxide.