Abstract Metal halide perovskites have aroused extensive attention due to their excellent photoelectric properties. But the toxicity and instability of lead-based perovskite restrict their development severely. Recently, lead-free Cu-based perovskites have emerged as promising environmental friendly photoelectric materials on account of their low toxicity and equally excellent properties. Here, we report the highly uniform lead-free Cs3Cu2I5 perovskite films with the long-term air-stability prepared by using methyl acetate as anti-solvent during the fabrication. The crystal structure, surface morphology, bandgap, and optical property of the Cs3Cu2I5 perovskite films are investigated. Even though the Cs3Cu2I5 perovskite films prepared with or without anti-solvent demonstrate the same crystal structure of the orthorhombic phase, by the anti-solvent approach, Cs3Cu2I5 perovskite films exhibit an enhanced photoluminescence quantum efficiency (PLQY) from ~62% to ~76.0% and have a relatively smaller surface roughness ~17.5 nm. Most importantly, Cs3Cu2I5 perovskite films exhibited long-term air-stability, and the PLQY could still reach 76.3% after storing for several months under an ambient atmosphere. All the results demonstrate the quality and the PLQY of Cs3Cu2I5 perovskite films could be effectively improved by the anti-solvent assisted crystallization strategy, showing potential applications in the fabrication of photoelectric devices based on lead-free perovskites.

中文翻译：

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具有高效蓝色光致发光的空气稳定均匀 Cs3Cu2I5 钙钛矿薄膜的绿色反溶剂辅助结晶策略

摘要 金属卤化物钙钛矿由于其优异的光电性能引起了广泛的关注。但铅基钙钛矿的毒性和不稳定性严重制约了其发展。最近，无铅铜基钙钛矿因其低毒性和同样优异的性能而成为有前途的环保光电材料。在这里，我们报告了在制造过程中使用乙酸甲酯作为抗溶剂制备的具有长期空气稳定性的高度均匀的无铅 Cs3Cu2I5 钙钛矿薄膜。研究了 Cs3Cu2I5 钙钛矿薄膜的晶体结构、表面形貌、带隙和光学性质。尽管使用或不使用反溶剂制备的 Cs3Cu2I5 钙钛矿薄膜表现出相同的正交相晶体结构，通过反溶剂方法，Cs3Cu2I5 钙钛矿薄膜表现出增强的光致发光量子效率（PLQY）从~62% 到~76.0%，并且具有相对较小的表面粗糙度~17.5 nm。最重要的是，Cs3Cu2I5 钙钛矿薄膜表现出长期的空气稳定性，在常温下储存数月后，PLQY 仍可达到 76.3%。所有结果表明，反溶剂辅助结晶策略可以有效提高 Cs3Cu2I5 钙钛矿薄膜的质量和 PLQY，显示出在基于无铅钙钛矿的光电器件制造中的潜在应用。Cs3Cu2I5钙钛矿薄膜表现出长期的空气稳定性，在常压下存放数月后PLQY仍可达到76.3%。所有结果表明，反溶剂辅助结晶策略可以有效提高 Cs3Cu2I5 钙钛矿薄膜的质量和 PLQY，显示出在基于无铅钙钛矿的光电器件制造中的潜在应用。Cs3Cu2I5钙钛矿薄膜表现出长期的空气稳定性，在常压下存放数月后PLQY仍可达到76.3%。所有结果表明，反溶剂辅助结晶策略可以有效提高 Cs3Cu2I5 钙钛矿薄膜的质量和 PLQY，显示出在基于无铅钙钛矿的光电器件制造中的潜在应用。