ScholarWorks@동국대학교

초록

Perovskite solar cells (PSCs) combine high power conversion efficiency (PCE) with low fabrication cost, yet their instability under ambient conditions remains a major barrier to commercialization. The protic nature of conventional A-site cations renders perovskite films vulnerable to moisture-induced degradation. Here, we demonstrate a mixed-dimensional (3D/1D) compositional engineering strategy using an aprotic additive, trimethylsulfonium bromide (TMSBr), to enhance both the moisture stability and photovoltaic performance of PSCs. Incorporation of TMSBr into a ternary-cation perovskite precursor promotes the in situ formation of one-dimensional TMSPbI<inf>3</inf> during preannealing, which organizes preferentially along the grain boundaries to form a 3D/1D heterostructure. The hydrophobic 1D TMSPbI<inf>3</inf> effectively suppresses water penetration owing to the weak interaction between TMS+ and H<inf>2</inf>O molecules, resulting in improved film crystallinity and suppressed intergranular degradation. Devices based on this architecture achieve a high PCE of 21.65% and retain over 84% of their initial efficiency after 40 days of ambient exposure. These findings highlight aprotic sulfonium additives as a promising route toward intrinsically moisture-stable and durable perovskite photovoltaics. © 2025 Wiley-VCH GmbH.

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