Effect of Laser Scribing on Coating, Drying, and Crystallization of Absorber Layer of Perovskite Solar Cells

Large-area perovskite solar modules fabrication has been demonstrated with a rapid process of large-area slot-die coating, drying, and crystallization using near-infrared radiation in ambient air, in which the laser-scribing process is applied to fabricate the modules. However, defective coating of perovskite layer near laser-scribed P1 line which isolates the front electrode of transparent conductive oxide (TCO) results very low module efficiencies. Therefore, systematic study is conducted to investigate the root cause, mechanism and solution of the defective coating and crystallization of the perovskite layer. Scanning electron microscope, energy-dispersive X-ray spectroscopy, and atomic force microscopy are used to characterize the TCO film before and after P1 scribing. It is found that P1 laser-scribing process changes surface morphology of TCO at the area near P1 line, which decreases the surface wettability and results discontinuous coating of precursor solution near P1 lines. The absence of TCO material in the P1 trench induces nonuniform heating during NIR annealing step, which is verified by thermal analysis via numerical simulation. After tuning laser process recipes, a large module with an active area of 46 cm2 is fabricated with a power conversion efficiency of 7.2% and geometry fill factor of 93.8%.