The light-emitting diodes (LEDs) used in indoor testing of perovskite solar cells do not expose them to the levels of ultraviolet (UV) radiation that they would receive in actual outdoor use. We report degradation mechanisms of p-i-n–structured perovskite solar cells under unfiltered sunlight and with LEDs. Weak chemical bonding between perovskites and polymer hole-transporting materials (HTMs) and transparent conducting oxides (TCOs) dominate the accelerated A-site cation migration, rather than direct degradation of HTMs. An aromatic phosphonic acid, [2-(9-ethyl-9H-carbazol-3-yl)ethyl]phosphonic acid (EtCz3EPA), enhanced bonding at the perovskite/HTM/TCO region with a phosphonic acid group bonded to TCOs and a nitrogen group interacting with lead in perovskites. A hybrid HTM of EtCz3EPA with strong hole-extraction polymers retained high efficiency and improved the UV stability of perovskite devices, and a champion perovskite minimodule—independently measured by the Perovskite PV Accelerator for Commercializing Technologies (PACT) center—retained operational efficiency of >16% after 29 weeks of outdoor testing.

中文翻译：

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强键合空穴传输层减少钙钛矿太阳能电池的紫外线降解


用于钙钛矿太阳能电池室内测试的发光二极管 (LED) 不会将其暴露在实际户外使用中会受到的紫外线 (UV) 辐射水平。我们报告了 p-i-n 结构钙钛矿太阳能电池在未经过滤的阳光下和 LED 下的退化机制。钙钛矿与聚合物空穴传输材料（HTM）和透明导电氧化物（TCO）之间的弱化学键主导了A位阳离子迁移的加速，而不是HTM的直接降解。芳香族膦酸，[2-(9-乙基-9H-咔唑-3-基)乙基]膦酸 (EtCz3EPA)，通过与 TCO 和氮键合的膦酸基团增强钙钛矿/HTM/TCO 区域的键合基团与钙钛矿中的铅相互作用。 EtCz3EPA 与强空穴提取聚合物的混合 HTM 保持了高效率并提高了钙钛矿器件的紫外线稳定性，而冠军钙钛矿微型模块（由钙钛矿光伏商业化技术加速器 (PACT) 中心独立测量）保持了 >16 的运行效率户外测试 29 周后的百分比。