In recent years, perovskite solar cells (PSCs) have emerged as a promising photovoltaic technology with significant potential to meet global energy needs. However, PSCs still need further development, especially in terms of scalability, in order to be commercialized.[1] Creating precise scribes on the perovskite solar modules (PSMs) is a very challenging task since it is crucial to ensure no damaging of the individual cells that form the modules, which is probable to occur when performing such thin scribes (~45 μm width each). Different methods such as shadow masks, mechanical scribing or laser ablation can be used to create those scribes, which are usually selected based on the deposition technique used.[2] Laser ablation offers numerous advantages, characterized by its versatility, precision and smoothness, making it an excellent method for ablating the scribes needed to create a well-organized module. Usually, the procedure used to make the scribes by laser ablation is the P1-P2-P3 process which consists of three scribings, each of which has a function in connecting the cells. P1 cuts the TCO on the substrate to pattern the sub-cell insulation. P2 scribing removes the HTL, perovskite, and ETL layers to form each sub-cell. In the P3 scribe, it is necessary to remove all layers, except for the bottom electrode (TCO), to separate each cell. This isolates the back-contact (electrode) of neighboring cells. The organization of a module can be quantified by the geometric fill factor (GFF), which is the ratio between the active area and the combined area of both active and dead regions within the module.[3]

This work focused on optimizing P1, P2 and P3 scribes for maximizing the GFF of inverted PSM (glass/FTO/PTAA/F-PEIA/Cs_0.05(FA_0.85MA_0.15)_0.95Pb(I_0.85Br_0.15)₃/F-PEIA/PCBM/BCP/Ag structure) with different number of individual cells. The laser ablation system used was a UV laser ablation system equipped with a UV laser source (355 nm) of 5 W power, with a pulse frequency range of 20 - 200 kHz and a minimum pulse width of 15 ns. Besides photovoltaic performance assessment, different techniques such as Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) were used to measure the scribe width and spacing between scribes, and to verify the presence of material residues on them. GFF of 99 % was reached for the described system with optimized P1, P2 and P3 scribes of 45 μm width each.