The Growth Mechanism And Properties Research On Cu₂O Micro/Nano-structures

In this thesis, several Cu2O micro/nanostructureswith different novel and complex structures were successfully synthesized via a template-free hydrothermal method. Due to the unique morphologies of Cu2O crystals, they are promising in the application areas of photocatalyst and field emission. Their time-dependent growth mechanism was proposed, and the controllable synthesis of Cu2O micro/nanostructures was achieved, which enriched the morphologies and the evolution procedure of Cu2O crystals in previous researches. The quasi-1D Cu2O micro/nano-structures were synthesized for the first time. The optical, electrical properties of as-prepared Cu2O crystals and their applications in the photocatalyst and field emission displays were studied in this thesis to explore the relationship between morphologies and their different properties. The investigation results indicated that the as-obtained Cu2O crystals had excellent photocatalytic performance for the degradation of Methyl Orange (MO). Besides, they also had very good field emission properties, which provided new promising candidate for the building blocks of field emission displays and high-efficiency electrical devices. The main contents and innovations of this thesis are as follows:1. All Cu2O micro/nano-crystals were synthesized via facile hydrothermal method. By adjusting and changing experimental conditions, such as source of copper, different solvent or surfactant, solution concentration, reaction temperature, and time, CU2O crystals with different morphologies, namely, micro/nano-particles, micro/nano-flowers, nanowires, micro-porous cubes etc., were successfully synthesized. The meso-1D hierarchical micro/nano-rods (be called as nano-bamboo shoots) were obtained for the first time.2. Field Emission Scanning Electron Microscopy (FESEM) and High Resolution Transmission Electron Microscopy (HRTEM) were applied to characterize the structures, sized and morphologies of as-prepared Cu2O crystals. X-Ray Diffraction (XRD) and Photoluminescence measurement (PL spectra) were used to analyze the structures, compositions, defects and optical properties of Cu2O crystals.3. The influence of experimental parameters on the evolution process, the initial and final morphologies of Cu2O micro/nano-crystals were discussed in detail in this thesis. Moreover, the controllable synthesis of Cu2O micro/nano-crystals was achieved, which improved the ability to artificially control the growth of complex micro/nano-structures.4. As to application, the photocatalytic activities of Cu2O crystals were measured by a UV-vis spectrophotometer for the degradation of MO solutions. Furthermore, the field emission properties of large scale Cu2O crystals were investigated by field emission measuring equipment with diode model. The relationship between the morphologies of Cu2O structures and their properties were further studied in detail. The Cu2O nano-bamboo shoots structures with large surface area and high aspect ratio had both excellent photocatalytic and field emission performance, indicating its potential application in these areas. The field emission performance of the Cu2O crystals was investigated for the first time, and the testing results were very promising.