Beyond 99.5% geometrical fill factor in perovskite solar minimodules with advanced laser structuring

Perovskite solar cells, known for high efficiency and compatibility with various photovoltaic (PV) applications, have garnered significant attention from academia and industry. Scaling up these cells conventionally involves fabricating modules with series-connected cells using a monolithic interconnection based on the P1-P2-P3 scheme, a common approach for thin-film PV modules. The Geometrical Fill Factor (GFF), representing the ratio between active area and aperture area, typically ranges from 90% to 95%. This study introduces an advanced laser manufacturing process to minimize interconnection area by reducing scribe width and minimizing distances between them, achieving an interconnection width of 45 mu m with a GFF of 99.1%. Additionally, a discontinuous P2 design further reduces the dead area to an average of 19.5 mu m, resulting in a record GFF of 99.6%. Using this interconnection in a highly efficient p-i-n stack, the study demonstrates the feasibility of the discontinuous P2 by fabricating 2.6 cm2 minimodules with an aperture area efficiency of 20.7%. The research highlights how proper design can minimize intrinsic losses during the scaling process from cell to module to a negligible level. Experimental studies, coupled with cell-to-module loss simulations and electroluminescence mapping for layer deposition uniformity, provide insights into the potential of the new P2 design.A novel discontinuous interconnection based on a dashed P2 contact is developed to minimize the efficiency losses from cell to module. In this way, it is possible to achieve a record geometrical fill factor of 99.6% (active area divided by the sum of active area and interconnection area), without inducing any resistive losses, achieving a minimodule efficiency of 20.6%.