Organic photovoltaics (OPVs) have recently achieved efficiencies of over 19% and are well underway toward practical applications. However, issues concerning operational stability remain a major challenge ahead of OPV commercialization. Here, when replacing the conventional hole-transporting layer PEDOT:PSS with a self-assembled monolayer of [2-(3,6-dichloro-9H-carbazol-9-yl)ethyl]phosphonic acid (3,6-Cl-2PACz) or [2-(4,5-dichloro-9H-carbazol-9-yl)ethyl]phosphonic acid (4,5-Cl-2PACz) it is found that the T₈₀ lifetime of PM6:BTP-eC9-based devices can be improved from ~100 to ~470 and over 800 h, respectively. The power conversion efficiency is also improved from 17.29% to 18.17% and 18.67%, respectively. The improved performance and prolonged photostability in 4,5-Cl-2PACz-based devices stem from the stabilized vertical distribution of donor and acceptor components, reducing the energetic disorder and thus alleviating non-radiative recombination losses. It is further found that the surface energy of 4,5-Cl-2PACz-modified substrates stays constant under prolonged illumination due to the improved intrinsic photostability of 4,5-Cl-2PACz, supporting the robust active layer morphology. Applying 4,5-Cl-2PACz in a ternary device of PM6:BTP-eC9:L8-BO-F delivered an efficiency of 19.05% and a T₈₀ lifetime over 1140 h.

中文翻译：

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通过形态稳定的空穴选择性自组装单层实现耐用的有机光伏

有机光伏 (OPV) 最近的效率已超过 19%，并且正在顺利走向实际应用。然而，运行稳定性问题仍然是 OPV 商业化之前的主要挑战。这里，当用[2-(3,6-二氯-9H-咔唑-9-基)乙基]膦酸(3,6-Cl-2PACz)的自组装单层代替传统的空穴传输层PEDOT:PSS时) 或 [2-(4,5-二氯-9H-咔唑-9-基)乙基]膦酸 (4,5-Cl-2PACz) 发现基于 PM6:BTP-eC9 的器件的T ₈₀寿命可以分别从约 100 提高到约 470 和超过 800 小时。功率转换效率也从 17.29% 分别提高到 18.17% 和 18.67%。基于 4,5-Cl-2PACz 的器件性能的提高和光稳定性的延长源于供体和受体组分的稳定垂直分布，减少了能量紊乱，从而减轻了非辐射复合损失。进一步发现，由于 4,5-Cl-2PACz 改进的固有光稳定性，4,5-Cl-2PACz 改性基材的表面能在长时间光照下保持恒定，支持稳健的活性层形态。在 PM6:BTP-eC9:L8-BO-F 三元器件中应用 4,5-Cl-2PACz 可获得 19.05% 的效率和超过 1140 小时的 T ₈₀寿命。