We present a design strategy for fabricating ultrastable phase-pure films of formamidinium lead iodide (FAPbI 3 ) by lattice templating using specific two-dimensional (2D) perovskites with FA as the cage cation. When a pure FAPbI 3 precursor solution is brought in contact with the 2D perovskite, the black phase forms preferentially at 100°C, much lower than the standard FAPbI 3 annealing temperature of 150°C. X-ray diffraction and optical spectroscopy suggest that the resulting FAPbI 3 film compresses slightly to acquire the (011) interplanar distances of the 2D perovskite seed. The 2D-templated bulk FAPbI 3 films exhibited an efficiency of 24.1% in a p-i-n architecture with 0.5–square centimeter active area and an exceptional durability, retaining 97% of their initial efficiency after 1000 hours under 85°C and maximum power point tracking.

中文翻译：

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用于耐用、高效甲脒钙钛矿太阳能电池的二维钙钛矿模板


我们提出了一种设计策略，通过使用以 FA 作为笼阳离子的特定二维 (2D) 钙钛矿的晶格模板来制造超稳定相纯碘化甲脒铅 (FAPbI 3 ) 薄膜。当纯FAPbI 3 前体溶液与2D钙钛矿接触时，黑相优先在100°C下形成，远低于标准FAPbI 3 退火温度150°C。 X射线衍射和光谱表明所得的FAPbI 3 薄膜轻微压缩以获得2D钙钛矿种子的(011)面间距。 2D 模板化块状 FAPbI 3 薄膜在 p-i-n 架构中表现出 24.1% 的效率，具有 0.5 平方厘米的活性面积和卓越的耐用性，在 85°C 和最大功率点跟踪下 1000 小时后仍保留 97% 的初始效率。