Multiscaled hierarchical nanostructures for enhancing the conversion efficiency of crystalline silicon solar cells

High-performance antireflection structure is critical for enhancing the conversion efficiency of solar cells. One of the most effective antireflection techniques for solar cells is the introduction of nanostructures to the cells. In this work, we prepared multiscaled hierarchical Er-doped ZnO nanostructures on the plasma enhanced chemical vapor deposited silicon nitride-coated texturized single crystalline silicon solar cells for antireflection. The multiscaled hierarchical Er-doped ZnO nanostructures were needle-like nanotip arrays, and they were grown using the hydrothermal method. The dependence of microstructure and antireflection performance of the multiscaled hierarchical Er-doped ZnO nanostructures on the growth time were studied. It was shown that longer growth time resulted in greater length and diameter for the Er-doped ZnO nanostructures. For longer growth time, the needle-like tips of the multiscaled hierarchical Er-doped ZnO nanostructures were found to transform to flat tops, which greatly degraded their antireflection performance. An optimal growth time for the multiscaled hierarchical Er-doped ZnO nanostructures was determined, and a large enhancement in the photovoltaic performance of sc-Si solar cells was resulted.