Maintaining the power conversion efficiency (PCE) of flexible perovskite solar cells (fPSCs) while decreasing their weight is essential to utilize their lightweight and flexibility as much as possible for commercialization. Strengthening the interfaces between functional layers, such as flexible substrates, charge transport layers, and perovskite active layers, is critical to addressing the issue. Herein, we propose a feasible and one-stone-for-two-birds method to improve the electron transport layer (ETL), SnO₂, and the interface between the ETL and perovskite layer simultaneously. In detail, poly(acrylate ammonium) (PAAm), a low-cost polymer with a long chain structure, is added into the SnO₂ aqueous solution to reduce the aggregation of SnO₂ nanoparticles, resulting in the deposition of a conformal and high-quality ETL film on the tin-doped indium oxide film surface. Simultaneously, PAAm addition can effectively regulate the crystallization of the perovskite films, strengthening the interface between the SnO₂ film and the buried surface of the perovskite layer. The outstanding PCEs of 22.41% on small-scale fPSCs and 18.54% on fPSC mini-modules are among the state-of-the-art n-i-p type fPSCs. Moreover, the fPSC mini-module on the 20 μm-thick flexible substrate shows a comparable PCE with that of the fPSC mini-module on the 125 μm-thick flexible substrate, exhibiting a high power-to-weight of 5.097 W/g. This work provides an easy but essential direction for further applications of fPSCs in diverse scenarios.

中文翻译：

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一石二鸟法改善高单位重量柔性钙钛矿太阳能电池微型模块的 SnO2 层


保持柔性钙钛矿太阳能电池（fPSC）的功率转换效率（PCE），同时减轻其重量，对于尽可能利用其轻质性和灵活性进行商业化至关重要。加强柔性基板、电荷传输层和钙钛矿活性层等功能层之间的界面对于解决这一问题至关重要。在此，我们提出了一种可行的一石二鸟的方法来同时改善电子传输层（ETL）、SnO ₂ 以及ETL和钙钛矿层之间的界面。具体而言，将具有长链结构的低成本聚合物聚丙烯酸铵（PAAm）添加到SnO ₂ 水溶液中，以减少SnO ₂ 的聚集。纳米粒子，从而在锡掺杂氧化铟薄膜表面沉积保形且高质量的 ETL 薄膜。同时，PAAm的添加可以有效调节钙钛矿薄膜的结晶，强化SnO ₂ 薄膜与钙钛矿层埋入表面之间的界面。小型 fPSC 的 PCE 为 22.41%，fPSC 迷你模块的 PCE 为 18.54%，属于最先进的 n-i-p 型 fPSC。此外，20μm厚柔性基板上的fPSC微型模块显示出与125μm厚柔性基板上的fPSC微型模块相当的PCE，表现出5.097W/g的高功率重量比。这项工作为 fPSC 在不同场景中的进一步应用提供了一个简单但重要的方向。