Perovskite solar cells (PSCs) have witnessed a meteoric rise in device performance. However, maintaining photostability, particularly under thermal stress, remains a challenge due to defect formation in the perovskite layer. This study introduces europium (III) trifluoromethanesulfonate [Eu(OTF)₃] as a multifunctional additive in two-step processed perovskite films, significantly improving the performance and high-temperature photostability of n-i-p PSCs. Density function theory (DFT) calculations reveal that the OTF⁻ anion strongly coordinates with Pb²⁺, effectively inhibiting iodine vacancy defect formation. The addition of Eu(OTF)₃ promotes perovskite grain growth to ≈2 µm and enhances film crystallinity. PSCs with a structure of ITO/SnO₂/perovskite/PDCBT/NiOx/Au achieve a champion power conversion efficiency (PCE) of 23.8%. Under 85 ± 5 °C and 1 sun illumination at an open circuit in ambient air, the PSCs with Eu(OTF)₃ retain 82% of their initial PCE after aging for 1500 h.

中文翻译：

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多功能三氟甲磺酸铕 (III) 添加剂增强钙钛矿太阳能电池的热稳定性和光稳定性


钙钛矿太阳能电池（PSC）的器件性能飞速提升。然而，由于钙钛矿层中的缺陷形成，保持光稳定性，特别是在热应力下，仍然是一个挑战。本研究引入三氟甲磺酸铕(III) [Eu(OTF) ₃ ]作为两步加工钙钛矿薄膜中的多功能添加剂，显着提高了n-i-p PSC的性能和高温光稳定性。密度函数理论（DFT）计算表明OTF ⁻ 阴离子与Pb ²⁺ 强配位，有效抑制碘空位缺陷的形成。 Eu(OTF) ₃ 的添加促进钙钛矿晶粒生长至约2 µm并增强薄膜结晶度。具有ITO/SnO ₂ /钙钛矿/PDCBT/NiOx/Au结构的PSC实现了23.8%的冠军功率转换效率（PCE）。在环境空气中开路、85 ± 5 °C 和 1 个太阳光照下，具有 Eu(OTF) ₃ 的 PSC 在老化 1500 小时后仍保留其初始 PCE 的 82%。