Two-dimensional Ruddlesden–Popper phase (2DRP) perovskites are known to exhibit improved photostability and environmental stability compared with their three-dimensional (3D) counterparts. However, fundamental questions remain over the interaction between the bulky alkylammoniums and the 2DRP perovskite framework. Here, we unambiguously demonstrate that a sulfur–sulfur interaction is present for a new bulky alkylammonium, 2-(methylthio)ethylamine hydrochloride (MTEACl). In addition to a weaker van der Waals interaction, the interaction between sulfur atoms in two MTEA molecules enables a (MTEA)₂(MA)₄Pb₅I₁₆ (n = 5) perovskite framework with enhanced charge transport and stabilization. The result is 2DRP perovskite solar cells with significantly improved efficiency and stability. Cells with a power conversion efficiency as high as 18.06% (17.8% certified) are achieved, along with moisture tolerance for up to 1,512 h (under 70% humidity conditions), thermal stability for 375 h (at 85 °C) and stability under continuous light stress (85% of the initial efficiency retained over 1,000 h of operation at the maximum power point).

二维Ruddlesden-Popper相（2DRP）钙钛矿与三维（3D）相比具有更好的光稳定性和环境稳定性。但是，有关庞大的烷基铵盐与2DRP钙钛矿框架之间相互作用的基本问题仍然存在。在这里，我们明确地证明，新的大体积烷基铵，2-（甲硫基）乙胺盐酸盐（MTEACl）存在硫与硫的相互作用。除了较弱的范德华相互作用外，两个MTEA分子中硫原子之间的相互作用还使得（MTEA）₂（MA）₄ Pb ₅ I ₁₆（n = 5）具有增强的电荷传输和稳定性的钙钛矿框架。结果是2DRP钙钛矿太阳能电池具有显着提高的效率和稳定性。电池的功率转换效率高达18.06％（经认证为17.8％），耐湿性长达1,512小时（在70％湿度条件下），热稳定性为375小时（在85°C时），在高温下具有稳定性持续的轻应力（在最大功率点运行1000小时后，仍保持初始效率的85％）。