Authors: Matteo Pitaro, Lorenzo Di Mario, Jacopo Pinna, Diego A. Acevedo‐Guzmán, Marios Neophytou, Mindaugas Kirkus, Thomas D. Anthopoulos, Giuseppe Portale, Petra Rudolf, Maria Antonietta Loi
Published: 2025-03-23
DOI: 10.1002/cey2.710
Source: Full article
ABSTRACTDespite the rapid efficiency increase, tin halide perovskite solar cells are significantly behind their lead‐based counterpart, with the highest reported efficiency of 15.38%. The main reason for this large difference is attributed to the instability of Sn2+, which easily oxidizes to Sn4+, creating Sn vacancies and increasing the open‐circuit voltage loss. In this work, we implemented tin thiocyanate (Sn(SCN)2) as an additive for passivating the bulk defects of a germanium‐doped tin halide perovskite film. Adding Sn2+ and SCN− ions reduces the Sn and iodine vacancies, limiting non‐radiative recombination and favoring longer charge‐carrier dynamics. Moreover, the addition of Sn(SCN)2 induces a higher film crystallinity and preferential orientation of the (l00) planes parallel to the substrate. The passivated devices showed improved photovoltaic parameters with the best open‐circuit voltage of 0.716 V and the best efficiency of 12.22%, compared to 0.647 V and 10.2% for the reference device. In addition, the passivated solar cell retains 88.7% of its initial efficiency after 80 min of illumination under 100 mW cm‐2 and is substantially better than the control device, which reaches 82.6% of its initial power conversion efficiency only after 30 min. This work demonstrates the passivation potential of tin‐based additives, which combined with different counterions give a relatively large space of choices for passivation of Sn‐based perovskites.