Interface engineering has significantly boosted perovskite solar cell efficiency and stability. However, numerous approaches focus on addressing defects at the interfaces between transport layers while neglecting potential issues within the bulk perovskite material. Here, a multifunctional molecule, sodium lignosulfonate (SL), containing three types of functional groups, was introduced as a chemical bridge at the perovskite/SnO₂ interface. The introduced SL bridges promote energy level alignment at the perovskite/SnO₂ interface and regulate the perovskite crystallization process. Meanwhile, the coordinated interactions between the perovskite components with −OH and −SO₃^– groups on SL, coupled with Na⁺ diffusion, effectively passivate defects at the buried interface and within the perovskite bulk. As a result, the champion SnO₂–SL based n-i-p PSC achieved power conversion efficiencies of 25.73% and 25.13% on rigid and flexible substrates, respectively. Unencapsulated devices maintained 92.9% of their initial efficiency after 2,550 h of maximum power point-tracking under 1-sun illumination in an inert atmosphere.

中文翻译：

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通过多功能化学桥接重建电子选择性界面，实现高性能刚性和柔性钙钛矿太阳能电池


界面工程显著提高了钙钛矿太阳能电池的效率和稳定性。然而，许多方法侧重于解决传输层之间界面处的缺陷，而忽略了块钙钛矿材料中的潜在问题。在这里，一种多功能分子木质素磺酸钠 （SL） 被引入，其中包含三种类型的官能团，作为钙钛矿/SnO₂ 界面的化学桥。引入的 SL 桥促进了钙钛矿/SnO₂ 界面的能级对齐并调节钙钛矿结晶过程。同时，SL 上 -OH 和 -SO₃^– 基团的钙钛矿组分之间的协调相互作用，再加上 Na⁺ 扩散，有效地钝化了埋藏界面和钙钛矿块体内的缺陷。结果，基于 SnO_2-SL 的冠军 n-i-p PSC 在刚性和柔性基板上分别实现了 25.73% 和 25.13% 的功率转换效率。在惰性气氛中，在 1 个太阳光照射下，未封装的器件在 2,550 小时的最大功率点跟踪后保持了 92.9% 的初始效率。