Shih Meng-Chen, Tan Shaun, Lu Yongli, Kodalle Tim, Lee Do-Kyoung, Dong Yifan, Larson Bryon W, Park Soyeon, Zhang Ruiqi, Grotevent Matthias J, Sverko Tara, Zhu Hua, Lin Yu-Kuan, Sutter-Fella Carolin M, Zhu Kai, Beard Matthew C, Bulović Vladimir, Bawendi Moungi G
Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
Molecular Foundry Division, Lawrence Berkeley National Laboratory, 67 Cyclotron Road, Berkeley, CA, 94720, USA.
Adv Mater. 2025 Apr;37(17):e2416672. doi: 10.1002/adma.202416672. Epub 2025 Mar 18.
Interface engineering plays a critical role in advancing the performance of perovskite solar cells. As such, 2D/3D perovskite heterostructures are of particular interest due to their optoelectrical properties and their further potential improvements. However, for conventional solution-processed 2D perovskites grown on an underlying 3D perovskite, the reaction stoichiometry is normally unbalanced with excess precursors. Moreover, the formed 2D perovskite is impure, leading to unfavorable energy band alignment at the interface. Here a simple method is presented that solves both issues simultaneously. The 2D formation reaction is taken first to completion, fully consuming excess PbI. Then, isopropanol is utilized to remove excess organic ligands, control the 2D perovskite thickness, and obtain a phase-pure, n = 2, 2D perovskite. The outcome is a pristine (without residual 2D precursors) and phase-pure 2D perovskite heterostructure with improved surface passivation and charge carrier extraction compared to the conventional solution process. PSCs incorporating this treatment demonstrate a notable improvement in both stability and power conversion efficiency, with negligible hysteresis, compared to the conventional process.
界面工程在提升钙钛矿太阳能电池性能方面发挥着关键作用。正因如此，二维/三维钙钛矿异质结构因其光电特性以及进一步的潜在改进而备受关注。然而，对于在底层三维钙钛矿上生长的传统溶液法制备的二维钙钛矿而言，反应化学计量通常因前驱体过量而失衡。此外，所形成的二维钙钛矿不纯，导致界面处能带排列不利。在此提出一种简单方法，可同时解决这两个问题。首先使二维形成反应完全进行，充分消耗过量的碘化铅。然后，利用异丙醇去除过量有机配体，控制二维钙钛矿厚度，并获得相纯的、n = 2的二维钙钛矿。结果是得到一种原始的（无残留二维前驱体）且相纯的二维钙钛矿异质结构，与传统溶液法相比，其表面钝化和电荷载流子提取得到改善。与传统工艺相比，采用这种处理方法的钙钛矿太阳能电池在稳定性和功率转换效率方面均有显著提升，滞后现象可忽略不计。
