The surface passivation with the heterostructure of the 2D/3D stack has been widely used for boosting the efficiency of n-i-p perovskite solar cells (PSCs). However, the disordered quantum well width distribution of 2D perovskites leads to energy landscape inhomogeneity and crystalline instability, which limits the further development of n-i-p PSCs. Here, a versatile approach, ligand-mediated surface passivation, was developed to produce a phase-pure 2D perovskite passivation layer with a homogeneous energy landscape by dual-ligand codeposition. The preferential adsorption of 3,6-dimethyl-carbazole-9-ethylammonium iodide with a large molecular size and lower adsorption energy could regulate the surface reaction between the m-fluorophenylethylammonium iodide and perovskite surface, resulting in a 2D perovskite with a narrow quantum well distribution and a uniform surface potential distribution. Beyond this, the preservation of the surface-confined 2D passivation layer retained a higher electric field at the interface of perovskite and the hole transport layer. As a result, the champion device reached an efficiency of 25.86% for the 0.05 cm² device and 25.08% for the 1 cm² device, with enhanced operational stability (T₉₀ > 1000 h) and much better thermal stability. Our work provides deeper insights into efficient and stable 2D passivation for PSCs.

中文翻译：

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配体介导的表面反应在高效钙钛矿太阳能电池中实现纯 2D 相钝化


具有 2D/3D 堆栈异质结构的表面钝化已被广泛用于提高 n-i-p 钙钛矿太阳能电池 （PSC） 的效率。然而，二维钙钛矿的无序量子阱宽分布导致能量景观不均匀和晶体不稳定性，从而限制了 n-i-p PSC 的进一步发展。在这里，开发了一种通用方法，即配体介导的表面钝化，通过双配体编码沉积产生具有均匀能量景观的相纯 2D 钙钛矿钝化层。分子粒径大、吸附能较低的 3,6-二甲基-咔唑-9-乙基碘化铵的优先吸附可以调节 m-氟苯乙基碘化铵与钙钛矿表面之间的表面反应，从而得到量子阱分布窄、表面电位分布均匀的二维钙钛矿。除此之外，表面限制的 2D 钝化层的保留在钙钛矿和空穴传输层的界面处保留了更高的电场。结果，冠军装置的 0.05 cm² 装置的效率为 25.86%，1 cm² 装置的效率为 25.08%，具有增强的运行稳定性 （T₉₀ > 1000 h） 和更好的热稳定性。我们的工作为 PSC 的高效和稳定的 2D 钝化提供了更深入的见解。