Hysteresis‐Free Planar Perovskite Solar Module with 19.1% Efficiency by Interfacial Defects Passivation

Abstract

In few years, perovskite solar devices have reached high efficiency on lab scale cells. Upscaling to module size, effective perovskite recipe and posttreatment are of paramount importance to the breakthrough of the technology. Herein this work, the development of a low‐temperature planar n–i–p perovskite module (11 cm2 aperture area, 91% geometrical fill factor) is reported on, exploiting the defect passivation strategy to achieve an efficiency of 19.1% (2% losses stabilized) with near‐zero hysteresis, that is the most unsolved issue in the perovskite photovoltaic technology. The I/Br (iodine/bromide) halide ion ratio of the triple‐cation perovskite formulation and deposition procedure are optimized to move from small area to module device and to avoid the detrimental effect of dimethyl sulfoxide (DMSO) solvent. The organic halide salt phenethylammonium iodide (PEAI) is adopted as surface passivation material on module size to suppress perovskite defects. Finally, homogeneous and defect‐free layers from cell to module with only 8% relative efficiency losses, high reproducibility, and optimized interconnections are scaled by laser ablation methods. The homogeneity of the perovskite layers and of the full stack was assessed by optical, morphological, and light beam–induced current (LBIC) mapping characterizations.