Fabrication of Efficient Perovskite Solar Minimodules with a High Geometric Fill Factor of 96% via a Nanosecond Laser

The low‐cost perovskite solar cell has become the next‐generation photovoltaic. However, compared to the high efficiency of the small‐area perovskite solar cells, the large‐area perovskite solar modules (PSMs) have still been struggling for the performance. In addition to preventing the decline in quality of each functional layer after upscaling, another key point is to construct a high geometric filling factor (GFF) for an efficient PSM. Herein, a “back‐scribing” technique is developed by using a low‐cost nanosecond laser scribing from the back side of substrates. The “back‐scribing” technology can clean up the scribing channels greatly, enabling an effective connection with a small damaged area. With precise control of the laser parameters for the scribing of P1, P2, and P3, a high GFF of 96% is achieved, resulting in a high power conversion efficiency of 19.97% with an aperture area of 16 cm 2 for the PSM. By this means, the efficiency loss is minimized (<10%) when upscaling a small device to a large‐area solar module.