Wang Xiaobo, Dong Xue, Dong He, Zhou Yipeng, Ran Chenxin, Song Lin, Liu Xiaowang, Xu Weidong, Huang Wei, Wu Zhongbin
Frontiers Science Center for Flexible Electronics (FSCFE), MIIT Key Laboratory of Flexible Electronics (KLoFE), Shaanxi Key Laboratory of Flexible Electronics, Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, Xi'an 710072, China.
Institute of Materials & Energy Science (TIMES), Xijing University, Xi'an 710123, China.
ACS Nano. 2024 Sep 12. doi: 10.1021/acsnano.4c08789.
Cesium-based two-dimensional (2D) perovskites with attractive phase and environmental stability have broad application prospects in single-junction and tandem perovskite solar cells (PSCs). However, the severe nonradiative recombination and significant energy losses due to disordered phase orientations and phase distributions greatly hinder the carrier transport performance of cesium-based 2D PSCs and severely limit their photovoltaic performance. Here, we employ an asymmetric chiral spacer cation source, ()-α-phenylethylamine acrylate (-α-PEAAA), to prepare high-quality 2D cesium-based films with uniform phase distribution and high out-of-plane orientation by air processing, resulting in efficient carrier transport. More importantly, the asymmetric chiral spacer -α-PEA has a stronger dipole moment than its isomer (PEA), which can regulate the dielectric properties of cesium-based 2D perovskites and promote charge dissociation. In addition, the chiral -α-PEA can optimize the morphology and out-of-plane orientation of perovskite films, reduce trap density and nonradiative recombination loss, and optimize energy level alignment, thus enhancing carrier transport. As a result, cesium-based 2D PSCs (-α-PEACsPbI, = 5) achieved a record power conversion efficiency of 19.71% and the unencapsulated device maintained over 90% efficiency after 1500 h of continuous light exposure and ambient storage (35 ± 5% relative humidity). This study provides an idea for the development of chiral 2D perovskite with efficient charge carrier transport toward efficient and stable cesium-based 2D PSCs.
具有吸引人的相稳定性和环境稳定性的铯基二维（2D）钙钛矿在单结和串联钙钛矿太阳能电池（PSC）中具有广阔的应用前景。然而，由于无序的相取向和相分布导致的严重非辐射复合和显著的能量损失极大地阻碍了铯基2D PSC的载流子传输性能，并严重限制了它们的光伏性能。在此，我们采用不对称手性间隔阳离子源（）-α-苯乙胺丙烯酸酯（-α-PEAAA），通过空气处理制备具有均匀相分布和高面外取向的高质量2D铯基薄膜，从而实现高效的载流子传输。更重要的是，不对称手性间隔基团-α-PEA比其异构体（PEA）具有更强的偶极矩，这可以调节铯基2D钙钛矿的介电性能并促进电荷解离。此外，手性-α-PEA可以优化钙钛矿薄膜的形貌和面外取向，降低陷阱密度和非辐射复合损失，并优化能级排列，从而增强载流子传输。结果，铯基2D PSC（-α-PEACsPbI，= 5）实现了创纪录的19.71%的功率转换效率，并且未封装的器件在连续光照1500小时和环境储存（相对湿度35±5%）后保持超过90%的效率。这项研究为开发具有高效电荷载流子传输的手性2D钙钛矿以实现高效稳定的铯基2D PSC提供了思路。
