Xu Zhiyuan, Lu Di, Liu Feng, Lai Hongtao, Wan Xiangjian, Zhang Xiaodan, Liu Yongsheng, Chen Yongsheng
The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
ACS Nano. 2020 Apr 28;14(4):4871-4881. doi: 10.1021/acsnano.0c00875. Epub 2020 Apr 7.
Two-dimensional (2D) perovskites with natural multi-quantum-well structure have been reported to offer better stability compared to 3D perovskites. However, the understanding of the exciton separation and transport mechanism in 2D perovskites and developing more efficient organic spacers remain considerable challenges, as the 2D perovskites exhibit large exciton binding energy due to quantum confinement. Here, a class of multiple-ring aromatic ammoniums, 1-naphthalenemethylammonium (NpMA) and 9-anthracenemethylammonium (AnMA), was developed as spacers for 2D Ruddlesden-Popper (RP) perovskite solar cells (PSCs). In addition to significantly enhanced stability, the device based on (NpMA)(MA)PbI (average = 4) exhibits a champion efficiency of 17.25% and a high open-circuit voltage of 1.24 V. The outstanding photovoltaic performance could be ascribed to the ultrafast exciton migration (within 7 ps) from 2D phases to 3D-like phases, which were confirmed by charge carrier dynamics results, leading to efficient exciton separation, charge transportation, and collection. This work facilitates understanding the working mechanism of 2D PSCs in-depth and offers an efficient way to further boost their efficiency and stability by developing multiple-ring aromatic spacers.
据报道，具有天然多量子阱结构的二维（2D）钙钛矿比三维钙钛矿具有更好的稳定性。然而，由于量子限制，二维钙钛矿表现出较大的激子结合能，因此深入了解二维钙钛矿中的激子分离和传输机制以及开发更高效的有机间隔层仍然是巨大的挑战。在此，一类多环芳香铵，即1-萘甲基铵（NpMA）和9-蒽甲基铵（AnMA），被开发用作二维Ruddlesden-Popper（RP）钙钛矿太阳能电池（PSC）的间隔层。除了显著提高稳定性外，基于（NpMA）（MA）PbI（平均 = 4）的器件表现出17.25%的最高效率和1.24 V的高开路电压。出色的光伏性能可归因于激子从二维相到类三维相的超快迁移（在7皮秒内），电荷载流子动力学结果证实了这一点，从而实现了有效的激子分离、电荷传输和收集。这项工作有助于深入理解二维PSC的工作机制，并通过开发多环芳香间隔层提供了进一步提高其效率和稳定性的有效方法。
