| Summary: | 博士 === 國立臺灣大學 === 光電工程學研究所 === 101 === This thesis explores various types of nanostructures in single junction hydrogenated amorphous silicon (a-Si:H) solar cells. The nanometer-sized structures are promising due to their excellent optical and electronic properties. They provide an effective way to increase optical path length inside solar cell, and thus result in improved energy conversion efficiency. This thesis is divided into two primary tasks: plasmonic nanoparticles and three-dimensional nanorods structures.
First, the plasmonic-structure incorporated multilayer of Au nanoparticles embedded in the transparent conducting oxide at the back reflector of a-Si:H solar cells is demonstrated. The effect of the nanoparticles density and the number of multilayer of the nanoparticles in tuning the plasmon resonances for better scattering are investigated by measuring optical characteristics. The double-layer Au nanoparticles structure has an advantage over single-layer for harvesting light. In addition to enhanced light scattering, applying high-work-function Au nanoparticles can improve the matching of work function at TCO/a-Si:H interface.
Second, the a-Si:H solar cells based on three-dimensional ZnO nanorods arrays prepared by hydrothermal growth is demonstrated. The influence of the absorber layer thickness and rod length on the performance of a-Si:H solar cells are investigated in detail. Focus in on the concept of applying three-dimensional nanorods for electronically thin and optically thick in achieving high efficiency a-Si:H solar cells.
Third, the a-Si:H solar cells based on random textures substrates incorporating ZnO nanorod arrays is demonstrated. Highly-oriented ZnO nanorods are grown on textured substrate (Asahi-U glass) through hydrothermal growth. It is found that the surface morphology and diffuse scattering property are strongly dependent on the concentration of reagents. By controlling the experimental conditions, the flower-like ZnO nanostructure is successfully obtained.
Fourth, in terms of previous tasks, plasmonic Au nanoparticles and three-dimensional nanorod arrays are combined to demonstrate a new type of nanoparticles decorated nanorods a-Si:H solar cell. The ultra-thin Au film are deposited on the surface of nanorods by thermal evaporation system to form Au nanoparticles. The scattering property between plasmonic nanoparticles and three-dimensional nanorods are investigated systematically. By optimizing thickness of Au metal film appropriately, the improved energy conversion efficiency is obtained for the nanoparticles decorated nanorods a-Si:H solar cell.
|
|---|
