Despite significant progress in the power-conversion efficiency (PCE) of perovskite solar cells (PSCs), the instability of devices remains a considerable obstacle for commercial applications. This instability primarily originates from the migration of halide ions—particularly iodide ions (I⁻). Under light exposure and thermal stress, I⁻ migrates and transforms into I₂, leading to irreversible degradation and performance loss. To address this issue, we introduced the additive 2,1,3-benzothiadiazole,5,6-difluoro-4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) (BT2F-2B) into the perovskite. The strong coordination between the unhybridized p orbital and lone-pair electrons from I⁻ inhibits the deprotonation of MAI/FAI and the subsequent conversion of I⁻ to I₂. The highly electronegative fluorine enhances its electrostatic interaction with I⁻. Consequently, the synergistic effect of BT2F-2B effectively suppresses the decomposition of perovskite and the defect density of the iodide vacancies. This approach delivers a PCE over 26% for inverted single-junction PSCs, with exceptional operational stability. According to the ISOS-L-3 testing protocol (maximum power point tracking at 85 °C and 50% relative humidity), treated PSCs retain 85% of their original PCE after 1000 h of aging. When the BT2F-2B is applied to a wide-bandgap (1.77 eV) perovskite system, the PCE of all-perovskite tandem solar cells reaches 27.8%, confirming the universality of the proposed strategy.

中文翻译：

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管理倒置单结和叠层钙钛矿太阳能电池中碘迁移的通用方法


尽管钙钛矿太阳能电池 （PSC） 的功率转换效率 （PCE） 取得了重大进展，但器件的不稳定性仍然是商业应用的巨大障碍。这种不稳定性主要源于卤化物离子的迁移，尤其是碘离子 （I⁻）。在光照和热应力下，I⁻ 迁移并转化为 I₂，导致不可逆的降解和性能损失。为了解决这个问题，我们在钙钛矿中引入了添加剂 2,1,3-苯并噻二唑，5,6-二氟-4,7-双（4,4,5,5-四甲基-1,3,2-二氧杂硼-2-基）（BT2F-2B）。来自 I⁻ 的未杂化 p 轨道电子和孤对电子之间的强配位抑制了 MAI/FAI 的去质子化以及随后 I⁻ 向 I₂ 的转化。高电负性氟增强了它与 I⁻ 的静电相互作用。因此，BT2F-2B 的协同作用有效抑制了钙钛矿的分解和碘化物空位的缺陷密度。这种方法为倒置单液接 PSC 提供了超过 26% 的 PCE，具有出色的操作稳定性。根据 ISOS-L-3 测试方案（在 85 °C 和 50% 相对湿度下的最大功率点跟踪），处理过的 PSC 在老化 1000 小时后仍保留其 85% 的原始 PCE。当 BT2F-2B 应用于宽带隙 （1.77 eV） 钙钛矿系统时，全钙钛矿叠层太阳能电池的 PCE 达到 27.8%，证实了所提策略的普遍性。