Energetics and Energy Loss in 2D Ruddlesden-Popper Perovskite Solar Cells
Energetics and Energy Loss in 2D Ruddlesden-Popper Perovskite Solar Cells
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二维 Ruddlesden-Popper 钙钛矿太阳能电池的能量学和能量损失
DOI：
10.1002/aenm.202000687
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发表时间：
2020
影响因子：
27.8
通讯作者：
Bao Qinye
中科院分区：
文献类型：
--
作者：
Yang Jianming;Xiong Shaobing;Song Jingnan;Wu Hongbo;Zeng Yihan;Lu Linyang;Shen Kongchao;Hao Tianyu;Ma Zaifei;Liu Feng;Duan Chungang;Fahlman Mats;Bao Qinye
2D Ruddlesden-Popper钙钛矿（RPP）由于其上级稳定性和竞争效率而成为其3D对应物的潜在挑战者。然而，2D RPPs的能量学的基本问题还没有得到很好的理解。在这里，系统地研究了（PEA）2（MA）n-1 PbnI 3 n +1/[6，6]-苯基-C61-丁酸甲酯（PCBM）界面的能量学，其中n值为1、3、5、40和∞。研究发现，在二维RPP界面（n= 3，5和40）上形成n-n结，而在纯二维和三维情形（n= 1和∞）下形成p-n结.显著降低表面功函数的碘化苯乙基铵配体之间的电势梯度促进光生电荷载流子的分离，其中电子在界面处从钙钛矿晶体转移到配体，减少电荷复合，这有助于基于2D RPP（n= 5）/PCBM的钙钛矿太阳能电池（PSC）中的最小能量损失和最高开路电压（Voc）。通过在PSC中的纯3D钙钛矿和PCBM之间插入薄的2D RPP覆盖层，使Voc显著增加94 mV，进一步验证了该机制。电容-电压测量与Mott-Schottky分析表明，suchVocimprovement归因于在界面处的电位增强。
2D Ruddlesden–Popper perovskites (RPPs) are emerging as potential challengers to their 3D counterpart due to superior stability and competitive efficiency. However, the fundamental questions on energetics of the 2D RPPs are not well understood. Here, the energetics at (PEA)2(MA)n−1PbnI3n+1/[6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) interfaces with varyingnvalues of 1, 3, 5, 40, and ∞ are systematically investigated. It is found that n–n junctions form at the 2D RPP interfaces (n= 3, 5, and 40), instead of p–n junctions in the pure 2D and 3D scenarios (n= 1 and ∞). The potential gradient across phenethylammonium iodide ligands that significantly decreases surface work function, promotes separation of the photogenerated charge carriers with electron transferring from perovskite crystal to ligand at the interface, reducing charge recombination, which contributes to the smallest energy loss and the highest open‐circuit voltage (Voc) in the perovskite solar cells (PSCs) based on the 2D RPP (n= 5)/PCBM. The mechanism is further verified by inserting a thin 2D RPP capping layer between pure 3D perovskite and PCBM in PSCs, causing theVocto evidently increase by 94 mV. Capacitance–voltage measurements with Mott–Schottky analysis demonstrate that suchVocimprovement is attributed to the enhanced potential at the interface.