2D Ruddlesden–Popper perovskite solar cells (PSCs) with structure formulated as R2MAn−1PbnI3n+1 (R is the organic bulky cation) exhibit superior environmental stability, but their efficiency still lags behind that of their 3D counterpart, which is mainly limited by the insufficient light absorption and carrier transportation. Herein, we incorporated guanidinium (GA+) into the PEA at the “R” site to form mixed bulky cations and investigated the doping effect of GA+ on the photovoltaic performance of layered 2D perovskites. Our results show that incorporating GA+ into the “R” site of 2D PSCs exhibits a stronger and wider light absorption, faster charge carrier mobility, and better quality perovskite films. Consequently, both the short circuit current density (Jsc) and fill factor (FF) of the 2D PSCs were significantly improved. As a result, the energy conversion efficiency (PCE) of the (PEA, GA)2MA4Pb5I16 champion device achieved 15.27%, which is much higher than the 11.58% PCE of the single cation 2D PSCs. Also, the 2D PSCs with the mixed (PEA, GA) cations exhibit improved environmental stability. Our work provides important guidance to obtain efficient and stable 2D PSCs through bulky cation engineering and modulating the interlayer interaction in 2D perovskite.

中文翻译：

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用于高效稳定的 Ruddlesden-Popper 钙钛矿太阳能电池的混合大体积阳离子

结构为 R2MAn−1PbnI3n+1（R 是有机大阳离子）的 2D Ruddlesden-Popper 钙钛矿太阳能电池 (PSC) 表现出优异的环境稳定性，但它们的效率仍然落后于 3D 对应物，这主要受制于光吸收和载流子运输不足。在此，我们在“R”位点将胍 (GA+) 掺入 PEA 中以形成混合的大体积阳离子，并研究了 GA+ 对层状二维钙钛矿光伏性能的掺杂影响。我们的结果表明，将 GA+ 结合到 2D PSC 的“R”位点表现出更强和更广泛的光吸收、更快的电荷载流子迁移率和更好的钙钛矿薄膜。因此，二维 PSC 的短路电流密度 (Jsc) 和填充因子 (FF) 均显着提高。因此，(PEA, GA)2MA4Pb5I16 冠军器件的能量转换效率 (PCE) 达到了 15.27%，远高于单阳离子 2D PSC 的 11.58% PCE。此外，具有混合（PEA、GA）阳离子的 2D PSC 表现出改善的环境稳定性。我们的工作为通过大体积阳离子工程和调节二维钙钛矿中的层间相互作用获得高效稳定的二维 PSC 提供了重要指导。