High-Resolution Image Patterned Silicon Wafer with Inverted Pyramid Micro-Structure Arrays for Decorative Solar Cells

Abstract Silicon (Si)-based solar cells have been widely used owing to their high conversion efficiency, high stability, and low cost. With the popularity of distributed photovoltaic systems, the appearance of photovoltaic panels has become more and more critical. However, compared to other types of solar cells, such as colored dye-sensitized and perovskite solar cells, the most widely used Si-based solar cells usually show a monotonous appearance. Here, we report the realization of high-resolution image patterned Si wafers by taking advantage of the inverted pyramid microstructure arrays. The digitized grayscale image is converted to the patterns that consist of inverted pyramid micro-structure units with different reflectivities. Then the patterns are transferred onto Si wafer through the processes of photolithography and dry/wet etching, enabling the construction of any grayscale image on the Si wafer with a resolution as high as 600 dots per inch (DPI) and a maximum contrast ratio of 4.7: 1. A laser ablation method, along with a circular pixel technology, is also developed to remarkably improve the patterning efficiency. Further, in combination with an optical anti-reflection layer, colored image patterned Si wafers are achieved. Our work demonstrates the enormous potential of image patterned Si solar cells for new-generation distributed solar energy systems with decorative features.