Organometallic halide perovskite solar cells (PSCs) have shown great promise as a low-cost, high-efficiency photovoltaic technology. Structural and electro-optical properties of the perovskite absorber layer are most critical to device operation characteristics. Here we present a facile fabrication of high-efficiency PSCs based on compact, large-grain, pinhole-free CH3NH3PbI3-xBrx (MAPbI3-xBrx) thin films with high reproducibility. A simple methylammonium bromide (MABr) treatment via spin-coating with a proper MABr concentration converts MAPbI3 thin films with different initial film qualities (for example, grain size and pinholes) to high-quality MAPbI3-xBrx thin films following an Ostwald ripening process, which is strongly affected by MABr concentration and is ineffective when replacing MABr with methylammonium iodide. A higher MABr concentration enhances I-Br anion exchange reaction, yielding poorer device performance. This MABr-selective Ostwald ripening process improves cell efficiency but also enhances device stability and thus represents a simple, promising strategy for further improving PSC performance with higher reproducibility and reliability.

中文翻译：

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通过CH3NH3Br选择性奥斯特瓦尔德（Ostwald）成熟，轻松制造用于高效太阳能电池的大颗粒CH3NH3PbI3-xBrx薄膜。

有机金属卤化物钙钛矿太阳能电池（PSC）作为低成本，高效率的光伏技术已显示出巨大的希望。钙钛矿吸收层的结构和电光特性对器件的工作特性最为关键。在这里，我们提出了一种基于紧凑，大晶粒，无针孔的CH3NH3PbI3-xBrx（MAPbI3-xBrx）薄膜的，高重复性的高效PSC的制造方法。通过采用适当的MABr浓度进行旋涂的简单甲基溴化铵（MABr）处理，通过奥斯特瓦尔德（Ostwald）熟化工艺，将具有不同初始膜质量（例如，晶粒尺寸和针孔）的MAPbI3薄膜转化为高质量的MAPbI3-xBrx薄膜，它受到MABr浓度的强烈影响，当用甲基碘化碘代替MABr时无效。较高的MABr浓度会增强I-Br阴离子交换反应，从而导致较差的器件性能。这种MABr选择性的Ostwald熟化工艺不仅提高了细胞效率，而且还提高了器件的稳定性，因此代表了一种简单而有前途的策略，可进一步提高PSC性能，并具有更高的再现性和可靠性。