Continuous Wet-process Growth Of ZnO Nano-array Based Wire-shaped Photoanode For Photovoltaic Cells

As a renewable, low-cost, green energy, solar energy is extremely expected to become a global energy, which would replace the fossil fuels. The traditional rigid flat photovoltaic cells have some problems with poor resistance of external force and restriction of large space which restricts the diversity of product and hinders the product development of industrialization. Recently, researchers try to use conductive fibers as electrode substrate to assemble into new photovoltaic cells through the winding or braiding method. Fiber photovoltaic cells with its unique flexible woven feature have brought great convenience to the application of solar cells.ZnO has a higher binding energy of electronic excitation and optical gain coefficient. ZnO nanorod arrays in nano-devices and solar cells extensively applied. The fiber photovoltaic cell substrate having a high surface curvature affects the growth of nanometers, making it difficult to shape regular, uniform, and this demand the growth process of ZnO nanorod array more difficulty.To enhance the fiber photovoltaic cell performance and reduce costs, the study basis on the Traditional Hydrothermal Method and introduction of the Continuous Wet-process Growth of new technologies to improve the quality of the electrode. It is more suitable for large scale growth. In this paper, research content mainly includes the following:(1)Aim at fiber photovoltaic cells base, based on the conventional batch hydrothermal method to grow ZnO nanorod arrays and optimize the concentration of zinc ion, reaction time, reaction temperature and other parameters.Then, the aspect ratio of the best prepared ZnO nanorod arrays samples assembled into fiber photovoltaic cells. But based on the experimental conditions optimized, single hydrothermal growth cannot further improve the thickness of the nano ZnO film, and zinc ionic concentrations have become an important factor restricting to grow nano ZnO film, the assembled battery performance is also difficult further enhanced.(2)Based on a single optimized conventional hydrothermal process and multiple hydrothermal growth of ZnO nano structure to break constraints of the zinc ionic concentrations, extending the growth time intermittently. Results showed that multiple hydrothermal growths made the length of nanorods increased significantly, nearly fourfold than a single thickness increased. In multiple hydrothermal growth process, the additive PEI can effectively inhibit lateral growth of nanorods. But multiple hydrothermal growth of ZnO nanorod array gives rise to form a fault structure, which would go against enhancing the fiber photovoltaic cell performance.(3)To meet the fiber photovoltaic cell application requirements and improve the quality of the electrode, this paper puts forward a continuous liquid phase growth method under normal pressure for preparing fiber photovoltaic cell anode light for the first time, ensuring that the course of the reaction solution composition uniformity and stability. Then, the flow field structure stable and controllable, this will be conducive to fine control the growth of ZnO nanorod array and large-scale. Experimental system optimize process parameters effect on the electrode structure, combined with CFD simulation system also analyzes the impact of the flow field structure on the electrode morphology. Results showed that Continuous Wet-process Growth and multiple hydrothermal have the same thickness for preparing ZnO-nano thin films, and there is no fault structure, which is beneficial apply to fiber photovoltaic cells of ZnO-nano thin films. It was found that the continuous growth assembled the photovoltaic cells, its performance better than the conventional hydrothermal.