Diaminopropane dihydroiodide passivation enables semitransparent perovskite modules for large-area four-terminal tandem solar cells

Scaling inverted perovskite solar cells from efficient small-area devices to semitransparent modules remains challenging, particularly for mid-bandgap absorbers used in tandem photovoltaics. Here, we investigate 1,3-diaminopropane dihydroiodide (PDADI) as an interfacial passivator for 1.61 eV tri-cation perovskites solar cells and further evaluate its applicability to semitransparent module scaling. PDADI treatment improves the perovskite film morphology, reduces the trap density, prolongs the carrier lifetime and optimizes the perovskite/PC61BM interfacial energy alignment, thereby suppressing interfacial recombination and improving charge extraction. Compared with previously reported diammonium-passivated inverted perovskite devices, the present strategy enables efficient and stable operation of a 1.61 eV tri-cation absorber while retaining its effectiveness upon scaling to a 15 cm 2 semitransparent module. The optimized inverted devices achieve a champion efficiency of 22.46%, with enhanced open-circuit voltage, improved fill factor and low hysteresis. The strategy remains effective after scaling, giving a certified PCE of 19.97% for 15 cm 2 semitransparent modules. When mechanically stacked with a TOPCon silicon bottom cell, the optimized mid-bandgap top module enables a certified four-terminal perovskite/silicon tandem efficiency of 27.95%. This work establishes a PDADI-based interfacial passivation strategy specifically for 1.61 eV tri-cation inverted perovskites and demonstrates its compatibility with semitransparent module fabrication and four-terminal tandem photovoltaics.