Lead halide perovskite solar cells (PSCs) have advanced rapidly in performance over the past decade. Single-crystal PSCs based on micrometers-thick grain-boundary-free films with long charge carrier diffusion lengths and enhanced light absorption (relative to polycrystalline films) have recently emerged as candidates for advancing PSCs further toward their theoretical limit. To date, the preferred method to grow MAPbI₃ single-crystal films for PSCs involves solution processing at temperatures ≳120 °C, which adversely affects the films’ crystalline quality, especially at the surface, primarily because of methylammonium iodide loss at such high temperatures. Here we devise a solvent-engineering approach to reduce the crystallization temperature of MAPbI₃ single-crystal films (<90 °C), yielding better quality films with longer carrier lifetimes. Single-crystal MAPbI₃ inverted PSCs fabricated with this strategy show markedly enhanced open-circuit voltages (1.15 V vs 1.08 V for controls), leading to power conversion efficiencies of up to 21.9%, which are among the highest reported for MAPbI₃-based devices.

中文翻译：

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低温结晶可实现21.9％的高效单晶MAPbI ₃倒钙钛矿太阳能电池

在过去的十年中，卤化钙钛矿型铅酸太阳能电池（PSC）的性能迅速提高。近来出现了基于具有微米级厚度的无晶粒边界的薄膜的单晶PSC，该薄膜具有长的载流子扩散长度和增强的光吸收能力（相对于多晶薄膜），可以作为进一步将PSC推向其理论极限的候选材料。迄今为止，生长用于PSC的MAPbI ₃单晶膜的首选方法涉及在≳120°C的温度下进行溶液处理，这主要是由于在如此高的温度下甲基碘化铵的损失，不利地影响了膜的晶体质量，尤其是在表面。在这里，我们设计了一种溶剂工程方法来降低MAPbI ₃的结晶温度。单晶膜（<90°C），可得到质量更好的膜，并具有更长的载流子寿命。采用这种策略制造的单晶MAPbI ₃反向PSC显示出明显提高的开路电压（对照为1.15 V对1.08 V），导致功率转换效率高达21.9％，是基于MAPbI ₃的最高报道效率之一。设备。