Preparation And Proprerhes Of Hierarchical ZnO And SnO₂ Nanostructures

Renewable energy sources represent a worldwide hot topic over recent years due to the inevitable exhaustion of traditional fossil energy sources and the accompanying serious environmental pollution. Solar energy as a recycle energy has attracted many attentions. Solar cells is one of the most important topics and photodegradation improve new route for serious environmental pollution problems. Among many materials, the wide-band-gap II-VI nanoscaled semiconductors have been extensively investigated because of their fndamental electronic and optical properties.ZnO and SnO2 are two important n-type wide-bandgap semiconductors with wide applications:ZnO owns the wide light absorption range which could be used as photocatalyst, SnO2 with a higher electron mobility (-125-250 cm2 V-11 S-1) can be used in solar cells. Different morphologies of low-dimensional ZnO and SnO2 nanostructures have been reported, such as zero-dimensional (OD) nanoparticles; one-dimensional (1D) nanowires and and two-dimensional (2D) nanosheets. Three dimensional (3D) nanostructures with complex morphology and high dimensionality have received great research interest due to the fact that their advanced geometric structure and atom arrangement on the specific facets of these nanostructures can offer novel properties. The synthesis of advanced functional nanomaterials in a controlled manner is thus of vital importance because it not only provides opportunities to reveal the relationships between material structure and property, but also helps to explore material fabrication techniques, as well as novel applications of such advanced nanostructures.In this paper, the main research is the preparation of ZnO and SnO2 hierarchical nanostructures. Then the structures and morphologies of as-prepared samples were investigated via XRD, SEM and TEM. Therefore, it is also explored that the properties of photocatalytic degradation and the photoelectric conversion efficiency of dye-sensitized solar cells. The main research can be divided into two systems:I Preparation and characterization of ZnO nanostructures.A novel zinc oxide with layer-stacked disc structure was prepared through a facile constant temperature bathing route. The physical properties of as-prepared samples were investigated. The results indicate that the sample phase belongs to wurtzite structure. The disk ZnO prepared with average diameter of 400 nm. The specific surface area of the disc structure was 28.14 m2/g and the average pore diameter is 10 nm. Moreover, the study focuses on optical properties and photocatalytic properties.II Preparation and characterization of SnO2 nanostructures.A SnO2 hollow nanosphere structure was prepared through a simple hydrothermal route. The physical performance test results indicate that the sample phase belongs to rutile phase structure. The SnO2 structures prepared with average diameter of 165 nm are superposed of nanoparticles with diameter of 10 nm. On the basis of the physical performance test, the photoelectric properties of the material are analyzed through the as-prepared structure as photoanode material of perovskite solar cells.III Preparation and characterization of ZnO NR/SnO2 NPs composite structure.The ZnO NR/SnO2 NPs composite structure was prepared through a two-step approach. The optical properties of the heterostructures were explored.